KINGDOM ANIMALIA

 KINGDOM ANIMALIA

Q.1: What are the diploblastic and triploblastic?

Ans: DIPLOBLASTIC AND TRIPLOBLASTIC ORGANIZATION:
Diploblastic are the animals whose body wall is composed of two layers: outer ectoderm and inner endoderm. Between these two layers, a non-cellular gelatinous layer called mesogloea is present.

Fig. 10-1(A): Diploblastic Organization (Hydra - T.S.)

Triploblastic are the animals whose body wall consists of three layers: outer ectoderm, middle mesoderm, and inner endoderm.

Fig. 10-1(B): Triploblastic Organization

Q.2: Write a note on Symmetry?

Ans: Symmetry:
A balanced structure and composition of the body according to the size and shape is called symmetry. It provides the least possible resistance in the movement of the body. There are two types of symmetry:

Bilateral Symmetry:
When the body can be divided into two equal halves by passing through the longitudinal axis, it is called a bilaterally symmetrical body. e.g., man, fish, etc.

Radial Symmetry:
When the body of an animal can be divided into two halves by more than one angle, it is called a radially symmetrical body, e.g., sea anemone. Animals with no plane of symmetry are called asymmetrical, e.g., sponges.

Fig. 10-2(A): Bilateral Symmetry (Man)
Fig. 10-2(B): Radial Symmetry (Sea-anemone)

Q.3: Write a note on Coelom?

Ans:
The internal body cavity of animals is called coelom. According to the coelom, the bilaterally symmetrical animals are divided into three groups.

• Acoelomata:
  These animals do not have a body cavity, e.g., Platyhelminthes (liver fluke, Planaria, etc.).

• Pseudocoelomata:
  These animals contain a primitive body cavity but do not have a true body cavity. It is considered a false cavity, present between the body wall and gut wall, e.g., Nematodes.

• Coelomata:
  These animals contain a true body cavity called coelom. In this cavity, all important organs are present, such as the alimentary canal, excretory organs, and reproductive organs, e.g., Earthworm, Chordate animals (fishes, reptiles, amphibians, birds, and mammals).

Fig.10-3(A): Acoelomate (No body cavity)
Fig.10-3(B): Pseudocoelomate (False Coelom)
Fig.10-3(C): Coelomate

Q.4: What are Protostomes and Deuterostomes?

Ans:
The coelomate animals (containing a true body cavity, coelom) are classified into two groups according to the fate of the blastopore.

• Protostomes: (Proto - First, Stoma - Mouth)
  In these animals, the blastopore is changed into the mouth, e.g., Annelids, Molluscs, Arthropodes.

• Deuterostomes: (Deutero - Second, Stoma - Mouth)
  In these animals, the blastopore is changed into the anus. The mouth is formed from another opening which is developed in the embryo after some time, e.g., Echinoderms, Chordates.

Q.5: Describe the important characters of Phylum Porifera?

Ans: IMPORTANT CHARACTERS PHYLUM PORIFERA:

• They are multicellular organisms. They are flat, cup-shaped, vase-shaped, bell, or fan-like. They have an asymmetrical body, i.e., have no plane of symmetry.
• They are sessile, i.e., do not move. They are attached to any solid object like stone or rock.
• Their body contains pores, called ostia. Through the ostia, water enters the body. The largest pore is known as osculum, through which the water is discharged out.
• Their body skeleton is composed of proteins, calcium carbonate, and silica. The skeleton has spiny structures, called spicules.
• They are diploblastic. Their body wall is composed of two layers, outer ectoderm and inner endoderm. Between these two layers, a middle region is also present, called mesenchyme.
• The cells of ectoderm are called pinacocytes; these are thin, flat, and scale-like. The cells of endoderm are called choanocytes. These cells are oval-shaped and flagellate. The cells which form pores in the body wall are called porocytes.
• The inner body cavity is called spongocoel. It is present with endodermal cells called choanocytes.

Spongocoel may be single or divided into many chambers. There are three types of sponges based on their body cavity:

1. Ascon type:
   Spongocoel consists of a single cavity.

2. Sycon type:
   The spongocoel divides into secondary chambers.

3. Leucon Type:
   The spongocoel divides into secondary and tertiary chambers.

• These animals do not have head, mouth, and alimentary canal. They use bacteria and organic matter as their food by filtration.
• They do not have a nervous system, respiratory system, or excretory system.
• Reproduction is by asexual and sexual methods.
• Asexual reproduction takes place by fragmentation and gemmule formation, and regeneration. Gemmule is a small body produced from amoeboid cells, covered by epithelial cells. During favorable conditions, it develops into new Porifera.
• Sponges are hermaphrodite (bisexual), but some are unisexual. Sperms are transferred into another sponge where fertilization occurs. After fertilization, the zygote develops into a free-swimming Amphiblastula larva. It is attached to the bottom, then develops into a new sponge.
• Examples: Sycon, Euplectella, Euspongia.

Q.6: Describe the important characters of Phylum Cnidaria?

Ans: Important Characters Of Phylum Cnidaria:

• They are simple aquatic animals. They have a radially symmetrical body.

Body Cavity - Coelenteron:

• Inside the body, a digestive cavity is present, called enteron or coelenteron. It opens to the outside by a single opening mouth.

Diploblastic Organization:

• They are diploblastic, i.e., their body wall consists of two layers, the outer layer is epidermis (ectoderm) and the inner layer is gastrodermis (endoderm), which is present along the body cavity. Between these two layers, a non-cellular gelatinous layer is found, called mesoglea.

Cnidocytes And Nematocytes (Defensive Organs):

• The mouth is surrounded by finger-like structures, called tentacles. The tentacles contain special cells, known as cnidoblasts. These cnidoblasts have capsule-like bodies, the nematocysts. These are the organs of offense and defense.

• Polyp And Medusa: The animals are of two types, one is polyp and the other is medusa. The polyp form is attached to a substrate at one end, e.g., Sea-anemone. The medusa animals are free-swimming, and they are not attached to any object (e.g., Physelia).

  Polymorphism: Many cnidarians live together to form a group or colony. In this colony, many individuals are physically attached together. This group formation is called polymorphism, e.g., Obelia, Physalia (Blue bottle). In polymorphism, polyp and medusa forms live together. In a group, two or more different types of animals are present, called zooids. These zooids collectively form a single species. The zooids perform different functions; such as:

  • Gastro-Zooid: They take food material.
  • Gono-Zooids: They are reproductive zooids.
  • Dactylo-Zooids: They are sensory zooids and they protect the animal.

  Respiratory, Excretory And Circulatory Systems: The cnidarians do not have proper respiratory, excretory, and circulatory systems. All these processes are performed by diffusion through the body surface.

  Nervous System: The nerve cells do not form the brain and spinal cord. They are present in the form of a network, so impulses are conducted in all directions more or less equally.

  Reproductive System: Asexual reproduction is mostly by regeneration and budding. Sexual reproduction also takes place in cnidarians by the fusion of male and female gametes.

Q.7: What are the Corals and Coral reefs?

Ans: CORALS & CORAL REEFS: Some cnidarians secrete a certain chemical substance which forms a protective covering around their body. These are called corals. They are of different shape and size. Underwater near the surface of the sea, coral reefs are formed. These are usually present in warm water. Along the Australian eastern coast, these reefs are found over hundreds of miles, this is called the Great Barrier Reef.

Corals are brightly colored. Red corals are used to make jewelry and other decorative items. In our country, Hakeems prepare an eastern medicine from red coral, commonly called Marjan.

Q.8: Describe the characters of Phylum Platyhelminthes?

Ans: IMPORTANT CHARACTERS:

• They have a flattened body on both sides, so they are called flat-worms. They have a bilaterally symmetrical body.

• They may be free-living, for example, Planaria; some are parasites and live in the body of other animals like Liver-fluke.

• They have a soft body without a skeleton.

• They are triploblastic animals, i.e., their body consists of three layers: outer ectoderm, middle mesoderm, and inner endoderm.

• A true body cavity (coelom) is not found, so they are acoelomate animals (without coelom).

• They have a single gastro-vascular cavity (alimentary canal). In some animals, this cavity is branched and opens to the outside by mouth only (e.g., Planaria). Some animals do not have a gastrovascular cavity, such as Cestodes (Tape worm).

• Blood vascular system is not present. The transportation takes place by diffusion.

• Respiration also takes place by diffusion through the external body surface.

• The nervous system consists of brain ganglia and a pair of connected nerve cords. They also have eye-spots.

• The excretory system takes place by flame cells or proto-nephridia. These cells absorb excretory products, which are discharged out of the body through the pores, called nephridiopores.

• They are hermaphrodite animals, i.e., male and female reproductive organs are present in the same body.

• The parasitic animals are either ectoparasites or endoparasites. They have suckers, which are used to attach them to the host body and to suck food material.

• Some parasitic animals complete their life cycle in the body of one host, and they are called monogenic. Some animals complete their life cycle in the body of two hosts; they are called digenic.

Examples Of Phylum:

• Planaria (Dugesia)
• Live fluke
• Tape worm (Taenia solium)

Q.9: What are the Parasitic adaptations of Flatworms?

Ans:
The parasitic adaptations of flatworms are as follows:

• They have thick body covering, which protects them from host body.
• They have suckers, hooks, and spines for proper attachment and sucking of food material. These are the replacement of locomotory organs.
• Their alimentary canal is reduced or absent in Taenia solium (tapeworm), because they absorb food from host body.
• Reproductive system is much developed and fertility rate is high to increase their number rapidly.

Q.10: What are the Precautions against diseases?

Ans: Precautions Against Diseases: Flatworms are mostly parasites and cause many diseases. The precautions and control measures are as follows:

• Hygienic life should be maintained.
• Sanitary conditions should be properly maintained.
• Careful inspection of edible items is necessary.
• Meat should be cooked properly to kill the parasites.

Q.11: Describe the important characters of Phylum Aschelminthes?

Ans: Important Characters:

• The Nematodes are also called roundworms. They have elongated and round bodies. The anterior and posterior ends are thin and pointed. They have bilaterally symmetrical body.
• The body is without segments. It is covered with a tough cuticle.
• They are triploblastic. Their body wall is composed of three layers, ectoderm, mesoderm, and endoderm.
• The nematodes have only longitudinal muscles. Circular muscles are not present. So they can only bend or swim poorly.
• The body cavity is a primitive cavity, called pseudo-coelom. It lies between the body-wall and gut-wall. The pseudo-coelom is considered as a false cavity.
• They have a complete digestive system.
• They have a circulatory system.
• The nervous system is composed of brain and nerve cords.
• The roundworms contain the essential and established characters of higher animals like digestive system, circulatory system, and nervous system.

Q.12: Describe the different diseases caused by Nematodes?

Ans: Diseases by Nematodes:

Elephantiasis or Filariasis (Thread Worm Disease)
It is caused by thread worm, Wuchereria. It is transferred into the body of man from blood sucking mosquitoes. When this mosquito bites a healthy person, this worm enters his body. It lives in lymphatic vessels and prevents the proper flow of lymph through the lymphatic vessels. As a result of this, hands, feet, and legs become extremely swollen; therefore, the disease is known as Elephantiasis.

This disease is very common in poor tropical countries. The main reason for spreading the disease is improper sanitary system in the area.

Hookworm Disease:
The hookworm, Ancylostoma enters the body of man in the form of larvae through the skin of man and finally enters the intestine. It lives there as a parasite and sucks the blood.

Ascaris Disease:
Ascaris lives in the intestine of children, lives as a parasite and uses the food of host body. It disturbs the growth and development of the children.

Q.13: Describe the important characters of Phylum Annelida?

Ans: Important Characters of Phylum Annelida:

• They have elongated and segmented body. Their segments are externally ring-like. These rings or external segments are called metameres.
• Their segmentation is called metameric segmentation, because the segmentation is both externally as well as internally.
• They have bilaterally symmetrical body.
• They are triploblastic animals i.e., the body consists of three layers, outer ectoderm, middle mesoderm, and inner endoderm.
• The alimentary canal is elongated and tube-like. It extends from mouth to the anus.
• These animals possess a true-coelom (true body cavity). It lies between the layers of mesoderm. Due to the presence of a true coelom they are called coelomates. There is development of coelomic compartments in their body.
• They have closed-type of circulatory system i.e., the blood flows in blood vessels. The blood is red due to the presence of hemoglobin of the major blood vessels are dorsal and ventral blood vessels. The number of hearts is two or more.
• There is no special respiratory organs. The respiration takes place through external surface of the body.
• The excretion is by convoluted tube-like organs, called nephridia. In each segment a pair or more nephridia are present.
• The locomotion of the body is by small hair-like structures, called setae. They are found along the segments in pairs: The setae or chaetae are with or without parapodia.

Q.14: Describe the important characters of Phylum Mollusca?

Ans: Important Characters:

• They have soft, unsegmented body with bilateral symmetry with organ system organization.
• They are triploblastic i.e. body consists of three layers, ectoderm, mesoderm, and endoderm.
• Alimentary canal is in the form of a straight or coiled tube with mouth and anus at the opposite side.
• Coelom is reduced, consists of few fluid-filled cavities, and makes a part of hydrostatic skeleton.
• Appendages are not produced from their body.
• From the lower side of their body, a special structure foot is developed, which helps in locomotion, sensation, and feeding.
• The upper layer of the body is called mantle. It produces shell for the protection of the body.
• The head is distinct. Mouth, eyes, and tentacles are present on the head.
• They have a dorsal visceral mass that includes major organs.
• In some animals, a special structure is produced in their mouth, called radula. It is used for scraping, tearing, and pulling of food.
• Respiration takes place by gills or lungs. In aquatic animals, gills are present, and in terrestrial animals, poorly-developed lungs are present.
• Excretion is by kidneys.
• Circulatory system is of open type, but the cephalopoda have closed type of circulatory system. Heart is present.
• Nervous system consists of a cerebral-ganglion, a pair of pedal nerves up to the foot and a pair of visceral body.
• Reproductive organs are found either in the same body or in separate bodies. Fertilization is in water.
• After fertilization, the egg develops into a larva, which is changed into an adult.
• The larva is of trochophore type.

Q.15: Describe the characters of class Bivalvia of Phylum Mollusca and Pearl formation?

Ans: Important Characters of Class Bivalvia:

• The head is not distinct.
• The shell consists of two pieces. It can be opened or closed. It has a hinge joint.
• The foot is large. It comes out from the opened shell and is used for locomotion or burrowing in sand.
• Respiration takes place by gills, which are thin and plate-like.
• Pearl formation: In Pearl Oyster Molluscs, pearl-formation takes place.

Q16: Describe the characters of Phylum Arthropoda?

Ans: Important Characters of Phylum Arthropoda:

• They have metamerically segmented and bilaterally symmetrical body.
• The body is covered by an outer covering, called exoskeleton. It is made up of proteins and chitin.
• Their body is triploblastic i.e. consists of three layers, outer ectoderm, middle mesoderm, and inner endoderm.
• The body of these animals is divided into head, thorax, and abdomen. In some animals, head and thorax are fused together to form Cephalothorax.
• From the body jointed legs or appendages are produced. The antennae, jaws, legs, and swimming organs are in pairs.
• Circulatory system is of open type i.e. blood vessels are absent, and the blood flows freely throughout the body.
• The body cavity is known as haemocoel, because the blood flows through it.
• The true body cavity coelom is very small and contains reproductive organs.
• The digestive system consists of a tube-like structure, which extends from mouth to the anus. Jaws are present.
• In terrestrial animals respiration is by trachea or book lungs. In aquatic animals, it is by gills.
• Nervous system consists of a brain in the anterior region (head) and a double nerve cord in the lower region of the body.
• They have compound eyes with mosaic vision.
• In insects and other animals, excretion takes place by malpighian tubules. In some animals, green antennary glands are the excretory organs.
• Sexes are found in separate bodies. Fertilization is internal. Development takes place by metamorphosis.

Q.17: What is Metamorphosis and describe its types?

Ans: Metamorphosis: The process of development from egg to the adult stage is called metamorphosis. It is of two types:

1. Incomplete Metamorphosis:

   • In this process, the egg is directly changed into a new individual which is similar to the adult, called nymph.
   • The nymph passes many stages of development. It becomes larger and mature, then finally changes into an adult, e.g., Cockroach, Grasshopper.

2. Complete Metamorphosis:

   • In this process, different stages are present, (i) egg, (ii) Larva, (iii) Pupa, (iv) Imago.
   • The egg produces larva. The larva may be of different types, maggot, grub, caterpillar, or worm-like.
   • The larva is an active form and takes its food from outside.
   • After many molts, the larva is changed into pupa. It covers itself by a protective coat and becomes inactive, using its internal stored food.
   • In pupa, internal major changes occur, and after a certain period, imago comes out.
   • The complete metamorphosis occurs in mosquito, butterfly, honey bee, etc.

Q.18: What are the advantages of Exoskeleton jointed appendages and wings?

Ans: Advantages of Exoskeleton Jointed Appendages and Wings:

• In arthropods, jointed appendages with exoskeleton are present. The jointed appendages help in walking, swimming, food capture, copulation, and sensory mechanism.
• The exoskeleton has the following advantages:
  • It is a protective covering around their body and appendages.
  • It makes them waterproof.
  • Exoskeleton is nonliving, after a particular period, it is shed down and new exoskeleton is formed. This process is called molting or ecdysis.
  • It also provides sites of muscle attachment. The muscles and jointed appendages work together and perform many functions, such as walking, swimming, flying, and other activities.
• Wings are the flying organs, helping in fast and easy movement of insects to other places.

Q.19: Name the classes of Phylum Arthropoda?

Ans: Phylum Arthropoda is divided into five classes:

• Class – Merostomata (with mouth plates) e.g., King crab (Limulus).
• Class – Arachnida (Spider-like animals) e.g., Scorpions, Spiders.
• Class – Crustaceae (with carapace) e.g., Prawn, Crab.
• Class – Myriapoda (with many legs) e.g., Centipedes, Millipedes.
• Class – Insecta or Hexapoda (with six legs) e.g., Butterflies, Mosquitoes, etc.

Q.20: Describe the characters of Class Insecta of Phylum Arthropoda?

Ans: Class – Insecta:

• The body of insects is divided into three parts, head, thorax, and abdomen.
• From the head, a pair of antennae is produced.
• Mouth parts are modified according to their function, such as:
  • Biting and chewing type e.g., Cockroach.
  • Piercing and sucking type e.g., Mosquito.
  • Chewing and lapping type e.g., Honey bee.
  • Sponging type e.g., Housefly.
  • Siphoning type e.g., Butterfly.
• Thorax is made up of three segments, prothorax, mesothorax, and metathorax.
• From the lower side of the thorax, three pairs of legs are developed for walking.
• From the upper side of the thorax, two pairs of wings are produced for flying.
• Respiration takes place by trachea. In aquatic insects, gills are present.
• Excretion occurs by malpighian tubules.
• Usually, sexual reproduction takes place, but in some insects parthenogenesis is also common, in which eggs are changed into adults without fertilization.
• In some insects, complete metamorphosis occurs, e.g., butterfly, and in some insects, incomplete metamorphosis takes place, e.g., cockroach, grasshopper.
• They have an open type of circulatory system.

Insects are of two types:

1. Pterigota: These insects have wings, e.g., Butterfly.

Apterigota:
These insects are without wings. e.g. Ants.

Q.21: Write down the successful characters of insects?

Ans: Insects - Successful Group:
Insects are considered a successful group of animals on the basis of many characters, such as:

• They are found everywhere, from lower regions up to the tops of the Himalayas, because they can tolerate temperatures up to 65°C. They can be found in hot springs, Antarctic low temperatures, and even in oil wells.
• They have developed mouth parts according to their need.
• They have a protective exoskeleton.
• They have wings for flying and jointed appendages.
• They have well-developed brain and sense organs.

Physiological Adaptations:

• They have proper digestion with digestive enzymes.
• They have a high reproductive rate and metamorphosis.

Q.22: Describe the characters of Phylum Echinodermata?

Ans: Important Characters of Phylum Echinodermata:

• They are all marine animals.
• Their larvae have bilaterally symmetrical bodies, but adults have radially symmetrical bodies.
• These animals usually have five parts or arms, so they are considered as pentaradial or pentamerous animals.
• Their body is unsegmented without a head and brain.
• They have a calcareous skeleton. The calcareous plates also bear spines, called spicules, so the phylum is called Echinodermata. The spines may be short in sand dollars or long as in sea urchins.
• They are triploblastic, i.e., the body has three layers: outer ectoderm, middle mesoderm, and inner endoderm.
• They contain a true body cavity, the Coelom. It is divided into five parts.

Q.23: Describe the characters of Hemichordata?

Ans: Important Characters:

• They have a soft, unsegmented body.
• Their body consists of three parts: proboscis, collar, and trunk.
• Sexes are separate. Fertilization is external. The zygote forms a larva, termed as tornaria larva. It develops into an adult animal.
  Example: Balanoglossus.

Q.24: Write down the important characters of Phylum Chordata?

Ans: Important Characters: The important characters of phylum Chordata which are different from other animals are as follows:

• Notochord:
  It is a solid rod-like structure present in the dorsal region of the body. In protochordata, it persists in adult animals, but in vertebrates, it is changed into a vertebral column.

• Pharyngeal Pouches And Gill Slits:
  They have pouches in the pharyngeal region, called pharyngeal pouches. These pouches open to the outside by gill slits.

Q.25: What is the brief classification of Phylum Chordata?

Ans: Classification of Phylum Chordata: Phylum Chordata is divided into two groups:

• Acraniata or Protochordata
• Craniata or Vertebrata

Group - Acraniata or Protochordata:

• They are simple chordates without a brain box or cranium, so the brain is not prominent.
• The notochord does not change into a vertebral column.

Group Acraniata is divided into two subphyla:

• Sub-phylum - Urochordata
• Sub-phylum - Cephalochordata

The two phyla Urochordata and Cephalochordata include soft-bodied marine animals. They are connecting links between vertebrates and invertebrates.

Q.26: Describe the important characters of Urochordata?

Ans: Sub-Phylum – Urochordata: (Notochord in the Tail) The animals of this phylum are called Tunicates or Sea-squirts.

• The characters of Chordata are only found in their larva but not in the adult stage. The larva has a nerve cord and notochord in its tail. In the pharynx, gill slits are present. When the larva is changed into an adult, the tail degenerates, therefore, the nerve cord and notochord disappear. Only gill slits are present in the adult stage. Due to the presence of notochord in the tail, they are called Urochordates.
• Their body is covered by a covering called tunic, so they are called tunicates.

Q.27: Describe the important Characters of Cephalochordata?

Ans: Important Characters of Sub-Phylum – Cephalochordata: (Notochord From Head to Tail)

• They are small fish-like animals. Their body is segmented and pointed at both ends. The segments are called myomeres. They are about 60 in number.
• The notochord is present from the anterior region to the tip of the tail.
• The pharyngeal region is large and contains many pairs of gill slits.
• The nerve cord is stretched through the entire region of the body.
• The sexes are found in separate animals, e.g., Amphioxus.

Q.28: Describe the important characteristics of Agnatha?

Ans: Important Characters of Sub-Phylum – Agnatha: (Mouth Without Jaws)

• Their body is elongated. They have a cartilaginous skeleton. They are cold-blooded animals.
• Their skin is soft, smooth, and without scales.
• They have a round mouth, so they are called cyclostomes. The mouth is without jaws.
• The tongue is spiny. In the mouth, many rings of teeth are present.
• The notochord does not change into a vertebral column. It remains in its original condition.
• Fertilization is external. Their larva is called ammocoete larva, which develops into an adult animal.

Q.29: Describe the characters of Chondrichthyes?

Ans: Class - Chondrichthyes or Elasmobranchii: (Cartilaginous Fishes)

In this class, Dog fish, Sharks, Skates, and Rays are included. Most of them are found in sea water. Their characters are as follows:

• They have a cartilaginous skeleton.
• Their body is covered by placoid scales i.e. denticle-like or enamel-covered scales.
• They have fins, a pair of pectoral fins, a pair of posterior fins, two median dorsal fins and caudal fin. They help in the movement. Their caudal (Tail) fin is hetero-cercal.
• Five pairs of gills are present which are not covered by any covering or operculum. The water passes outside through the gill slits. Gills are the respiratory organs.
• The heart consists of two chambers, one atrium and one ventricle. The circulatory system is of closed type.
• Eyes are without eyelids.
• Excretion takes place by kidneys.
• The sexes are separate and fertilization is internal. In some sharks ovo-viviparous reproduction takes place in which the female sharks retain eggs within their bodies until the partial development of young sharks.

E.g. Sharks, Skates, Electric ray (Torpedo), Dog fish (scoliodon or small shark). These are commonly found on our coasts.

Q.30: Describe the characters of Osteichthyes?

Ans: Class - Osteichthyes: (Bony Fishes)

The characters of these fishes are as follows:

• Their body consists of three parts: head, trunk, and tail.
• Their body is covered by scales, called cycloid or ctenoid. These plates form exoskeleton.
• Their skeleton is made up of bones (Bony skeleton).
• Respiration takes place by four pairs of gills. The gill slits are covered by a hard covering, the operculum.
• They contain an air bladder which is not used for respiration. It regulates buoyancy i.e., helps in swimming.

Q.31: Write a note on Dipnoi (Lung Fish)?

Ans: Lung Fishes: Lung fishes belong to the order Dipnoi of class osteichthyes. These fishes contain lungs which are the modified organs of air bladders. These fishes respire by gills or the modified lungs. They can live without water for several months. These fishes are found in South America, Africa and Australia.

Q.32: Describe the important characters of Class Amphibians?

Ans: Characters of Amphibians:

• The amphibians can live both in water and on dry land.
• They are cold-blooded animals (poikilotherms), i.e. their body temperature can change according to the environment.
• They have bony skeleton with strong back bone (vertebral column) and pairs of limbs. Notochord is replaced by vertebral column.
• Their skin is soft, thin and moist. It takes part in respiration. Respiration also occurs by lungs and buccal cavity. In larva the respiration is by gills.
• The heart is advance than fishes. It is three chambered, two atria (auricles) and one ventricle.
• Eyelids are present. The eyes contain tear-glands to keep them moist during dry season.
• External ear is absent, only internal ear is present.
• During winter they take rest in mud, it is called hibernation. During this period they become inactive and use their internal reserve food. Some animals also take rest during summer, it is called aestivation.
• They lay their eggs in water, Fertilization is external. The zygote develops from the yolk of egg and changes into tadpole larva. It respires by gills and feeds on aquatic plants. The larva develops into an adult animal by metamorphosis.

Q.33: Write a note on Amphibia on unsuccessful land vertebrates?

Ans: Amphibia as Unsuccessful Land Vertebrates: Amphibians are considered as unsuccessful land vertebrates, because:

• Amphibians are cold-blooded animals. They face the problem of change in temperature.
• Their skin is smooth without scales or any exoskeleton, so they cannot be protected from extreme temperature, so they live close to water places.
• There is quick loss of water in air which is dangerous for the animal.
• Their eggs are small and without any shell, so their development occurs in water, it indicates unsuccessful land adaptation.
• Their eggs do not contain sufficient yolk for complete development, the larva comes out earlier in water and respires by gills.

All these points indicate that amphibians need water during different conditions of their life, so they are the unsuccessful land vertebrates.

Q.34: Describe the important Characters of Reptiles?

Ans: Important Characters of Reptiles:

• They are poikilotherms, i.e., cold-blooded animals. They also take rest during winter like amphibians, called hibernation.
• Their skin is dry and covered by scales.
• Their body has bony skeleton.
• They have two pairs of legs, each with five claws. They are used for rapid locomotion. Snakes have no limbs.
• The heart consists of two atria (auricles) and one incompletely divided ventricle and thus separation of oxygenated and deoxygenated blood is not complete. In crocodile the heart has completely divided into two ventricles.
• Respiration takes place by lungs.
• Excretion is by kidneys.
• Fertilization is internal. They lay eggs which are large and surrounded by outer shell.
• The development of embryo takes place inside the shell, the yolk of egg provides energy. In the egg a protective membrane is present, called amnion, so they are called amniotes. This membrane is also found in birds and mammals.

Q.35: Write a note on Reptiles as successful land vertebrates?

Ans: Reptiles as Successful Land Vertebrates: Reptiles are the first successful animals on land. Their adaptations on dry places are as follows:

• They have exoskeleton of horny scales and plates on their skin, so they can sustain the frequent change in the temperature. There is also less water loss from the body.
• They have developed kidneys to retain sufficient water and excretion of urine.
• They have developed limbs with claws. These are used in proper movement, digging and climbing. These are also used for their defence against their enemies.

Q.36: What are the common reptiles of World and Pakistan?

Ans: Common Reptiles: The common reptiles are tortoise, turtles, lizards, snakes, crocodiles, alligators. A living fossil Sphenodon is found in New Zealand only.

Reptiles of Pakistan: In Pakistan, many species of tortoise and turtles are found, e.g., Chelone mydas (Green turtles). Wall lizard, Garden lizard, Uromestic, Crocodiles, and Snakes are common. Cobra, Viper, Krait, Python, and other snakes are common in Pakistan.

Q.37: Write a note on snakes?

Ans: Snakes: The snakes are limb-less lizards. They live in burrows. Their eyes are without eye-lids. Some snakes are terrestrial and some are water-living. Certain kinds of snakes are poisonous. The poison is produced in specially modified salivary glands which is transferred into the body of prey through their teeth (Fangs). This venom (poison) is the mixture of certain substances which attacks the nerves and blood thus it usually causes death of the prey.

Q.38: Describe the important characters of Class Aves?

Ans: Important Characters of Class Aves (Birds):

• They are warm-blooded animals (Homeotherms). They can regulate their internal body temperature.
• The body is covered by feathers which trap air and prevent the loss of body heat.
• They have a bony skeleton. Bones are hollow, thin, and light.
• Fore limbs are modified into wings for flying.
• Eyes are large with eyelids.
• External ear is absent, but sense of hearing is well developed.
• The neck has great mobility which helps in feeding, nest building, preening and defence.
• Mouth parts are modified into beak. Teeth are absent. The shape of beak is modified according to the function in different animals.
• Hind limbs have claws.
• Respiration takes place by lungs. The lungs also contain air sacs for the storage of air.

Q.39: Describe the different classes of birds or non-flying and flying birds?

Ans: Classification of Birds: The birds are classified into two sub-classes:

• Sub Class - Ratitae (Sternum raft like): These are heavy non-flying birds.
• Sub Class - Carinatae (Sternum with keel): They are small flying birds.

Sub Class — Ratitae: (Non-Flying Birds)

• They are big-sized, flightless heavy birds.
• They cannot fly due to their heavy weight. The weight of Ostrich is 150 kg.
• Their wings are vestigial or rudiments i.e., very much reduced and functionless.
• Their sternum is flat without keel.
• Their flight muscles are poorly developed.

Sub Class — Carinatae: (Flying Birds)

• They are all modern flying birds.
• They are small, with light weight.
• Their wings are highly developed.
• Feathers of wings have interlocking mechanism.
• Their sternum has a crest like keel to support the flight muscles.

Q.40: What are the common birds of Pakistan?

Ans: Common Birds of Pakistan: Sparrow, Pigeons, Myna, Bulbul, Hoopoes, Crow, Doves, Parrots, Fowls, Cuckoo, Ducks, Kites, Falcons and Owls are common prey birds. Ducks, Sea gull Terns and Granes are migratory birds. Peacock and Houbara are the most beautiful birds.

Q.41: Describe the flight adaptations in birds?

Ans: Flight Adaptations in Birds:

• Wings: They have special organs for flying, called wings. These are the modified form of fore-limbs.
• Feathers: Their body is covered by feathers which help to maintain the body temperature and prevent the loss of body heat.
• Sternum with Strong Muscles: The body structure is modified for flying. The sternum, central part of pectoral girdle is larger and strong for the attachment of wing-muscles and better support.
• Light & Hollow Bones: Their bones are hollow and light for easy flight.
• Blood Circulation: Their heart consists of four chambers and circulatory system is very fast. It helps to maintain the blood pressure and to control the amount of oxygen.
• Energy Requirement: The metabolism of the body is very rapid and fast, so great amount of energy is produced which is used in flying and maintains the body temperature. It is due to rich supply of O₂ from heart and by extra ordinary respiratory system. The lungs are supplemented by a number of air-sacs. They store air which is used during flight.
• Maintenance of Body Temperature: They are warm-blooded animals. The muscular activity rises temperature but it is maintained by the ventilating action (exchange of warm and cold air) of air sacs.

Q.42: Describe the important characters of Class Mammalia?

Ans: Important Characters:

• They are warm-blooded animals (Homoiotherms). They have constant body temperature which remains between 37°C–40°C.

Q.43: What are the different classes of Class Mammalia?

Ans: Classification of Mammalia: The class mammalia is divided into three sub-classes.

• Sub-class - Prototheria (Egg laying mammals)
• Sub-class - Metatheria (Pouched mammals)
• Sub-class - Eutheria (Placental mammals)

Sub-Class – Prototheria:

• It is a very primitive class. The animals of this class are egg-laying (oviparous).
• They do not have ear pinna like reptiles.
• They have cloaca i.e. the common opening of rectum and urogenital system, so they are considered as connecting link between reptiles and mammals.
• Their body is covered by hairs.
• They have mammary glands to provide nourishment to their young ones. e.g. Platypus (Duck bill), Spiny ant eater.
• This sub-class has single order, Monotremata, so they are also called monotremes.

Sub-Class – Metatheria:

• These animals have pouch along their abdomen, so they are called pouched mammals.
• Their immature young ones are migrated into the pouch, called Marsupium.
• In the pouch mammary glands are present. The young ones get their food from these mammary glands.
• They are viviparous i.e. they produce young ones.
• Their eggs are not laid. Fertilization is internal.
• Their eggs do not contain sufficient yolk, so immature young ones are produced in the pouch.
  • E.g. Kangaroo, Koala bear, Wombats, Opossums.

Sub-Class – Eutheria: These are the placental mammals. The development of their embryo takes place in the uterus. There is a cord between mother and the embryo, called placenta, through which food and oxygen are supplied. The mother takes care of her young after birth and feeds from mammary glands.

• E.g. Cow, Monkey, Elephant, Dog, Cat, Rat, and Man.

• Small Eutherian Mammals:

  • Squirrels, Rabbits, Hedgehogs, Rats, Scaly ant eaters.

• Ungulates (Hoofed Mammals):

  • Sheep, Goats, Cows, Deers, Camels, Giraffes, Horses, Donkeys, Zebras, Rhinoceros etc.

• Carnivores:

  • Cats, Dogs, Lions, Tigers.

• Omnivores:

  • Bear, Man. Large placental mammals are Elephants and Whales.

• Flying Mammal:

• Bat.

Q.44: Distinguish between the following:

Chondrichthyes & Osteichthyes:

Chondrichthyes	Osteichthyes
These are cartilaginous fishes i.e. they have cartilaginous skeleton.	These are bony fishes i.e. they have bony skeleton.
Their skin is covered by placoid scales, which are sharp enamel-coated scales.	Their skin is covered by cycloid scales, which are thin bony plate-like scales.
They contain 5 exposed gill slits on each side, without operculum.	Their gills are covered by operculum.
Their tail fin is heterocercal. E.g. Sharks, Skates, Dog-fish.	Their tail fin is homocercal. E.g. Sea horse, Eal fish, Globe Fish, Flying fish

Poikilotherms & Homeotherms:

Poikilotherms	Homeiotherms
These are cold-blooded animals i.e. their body temperature is changed according to their environment.	They are warm-blooded animals i.e. their body temperature remains constant.
Show hibernation during winter season.	They do not show hibernation during winter season.
Show aestivation during summer season.	They do not show aestivation during summer season.
Their body is either smooth or covered by scales. E.g. Fishes, Amphibians, Reptiles	Their body is covered by feathers or hairs. E.g. Birds, Mammals

Incomplete Metamorphosis & Complete Metamorphosis:

Incomplete Metamorphosis	Complete Metamorphosis
In this metamorphosis there are only two stages, egg stage and Nymph Stage (young insect).	In this process there are four stages, egg stage, larva stage, pupa stage and imago stage.
In this process complete development occurs in the egg.	In this process initial development occurs in the egg, then larva comes out.
Larva and pupa stages are absent. E.g. Cockroach, Grasshopper	Larva and pupa stages are present. E.g. Butterfly, Mosquito

Class Ratitae & Class Carinatae:

Class Ratitae	Class Carinatae
These are non-flying birds.	These are flying birds.
They are big-sized, heavy birds.	They are small-sized with light weight.
Their wings are vestigial or reduced and functionless.	Their wings are highly-developed.
Their sternum is flat without keel.	Their sternum has a crest-like keel to support the flight muscles.
Their flight muscles are poorly developed.	Their flight muscles are well-developed.

The Kingdom Plantae

 Biology XI Notes

The Kingdom Plantae - Short Questions Answers

Chapter # 09
Short Questions Answers
Section III - Biodiversity

THE KINGDOM PLANTAE

Q.1: Write a note on classification of Plants?

Ans: Classification of Plants:
Kingdom plantae is classified into two divisions:

• Division – Bryophyta (Non vascular plants)
• Division – Tracheophyta (Vascular plants)

Division Bryophyta: (Non-Vascular Plants)
This division is divided into three classes:

• Class – Hepaticae (Liverworts)
• Class – Musci (Mosses)
• Class – Anthocerotae (Hornworts)

Division Tracheophyta: (Vascular Plants)
This division is divided into five sub-divisions:

• Sub-division - Psilopsida (Psilopsids)
• Sub-division - Lycopsida (Club Mosses)
• Sub-division - Sphenopsida (Horse tail)
• Sub-division - Pteropsida (Ferns)
• Sub-division - Spermosida (Seed plants)

Q.2: What are the Characters of Bryophyta?

Ans: Characteristics of Bryophyta:
These plants include liverworts hornworts and mosses.

• These plants are found in humid and shady places. They are land-inhabiting plants. They are non-flowering plants.
• Bryophytes are autotrophs i.e. they contain chlorophyll and can manufacture their own food material.
• They are small plants. Their body is thallus like or the body is divided into stem and leaves.
• True root is absent in Bryophytes, but hair-like structures arise from the lower part of the plant, called rhizoids. They help in the attachment of plant body to the soil and as well as in the absorption of water.
• In their life cycle heteromorphic alternation of generations is present.
• Their main body is gametophyte, which is the first stage of their life cycle.
• They do not possess vascular tissues.
• Division Bryophyta is divided into three classes:
• Class – Musci (Mosses)

Q.3: Describe the Life Cycle of Bryophyta (Funaria)?

Ans: LIFE CYCLE OF BRYOPHYTA (FUNARIA HYGROMETRICA):
Moss (Funaria) is a small plant, grows on moist places. The life cycle shows heteromorphic alternation of generations. The life cycle is completed into two stages:

Gametophytic Stage:
It is the first and dominant phase of life cycle. In this phase male and female reproductive organs are produced, antheridia (male) and archegonia (female).

• The Antheridia:
  The antheridia are club-shaped. Inside the antheridium motile biflagellate antherozoids (male gametes) are produced.

• The Archegonia:
  Each archegonium is flask-shaped. It consists of stalk, venter and neck. The stalk helps in the attachment of archegonium. Venter is the middle swollen part. It contains a large egg cell and a smaller venter canal cell. Neck is the upper elongated tube-like part. It contains neck-canal cells.

• Fertilization:
  The motile antherozoids move towards the archegonium in the presence of water. They enter the archegonium through its open mouth and one spermatozoid fuses with egg cell, with the result the zygote (2n) is formed.

Sporophytic Stage:
The zygote develops into sporophyte. The sporophyte grows upon gametophyte, it depends partially or completely for its nourishment upon the tissues of gametophyte.

The sporophyte consists of three parts, foot, seta and capsule. Foot helps in the attachment of sporophyte and in the absorption of food from the tissues of gametophyte. The seta is the stalk of capsule. The capsule produces spore-mother cells. They are diploid (2n). They divide by meiosis and form haploid (n) spores. Each spore can germinate into a new gametophyte during favorable conditions.

Q.4: Write a note on plants become adapted to land?

Ans: PLANTS BECOME ADAPTED TO LAND:
It is the opinion of all biologists that the land plants and animals have been evolved from aquatic living organisms. On land they got their control after a difficult and long period.

The life of aquatic living organisms is easy, because water is essential for all processes of life. The aquatic organisms do not face dry conditions. The carbon compounds are abundant in the sea which are used in photosynthesis. The plant releases oxygen during photosynthesis which is utilized by animals. The temperature of sea-water does not charge very rapidly like dry land. In this way the life of aquatic living organism’s remains continue in a normal way.

When the plants migrated on land, they faced certain problems. The most important ones are as follows:

• To obtain and conserve water.
• To absorb CO₂ from the atmosphere for photosynthesis.

To solve these problems, the plants changed their body structure according to the environment. First of all, they shifted from aquatic to the amphibious habitat, then they started their life on dry land. Amphibians are the plants which grow on moist places or live both in dry and wet habitats. For example, Mosses and Liverworts.

The characteristics of plants which are migrated from wet to dry conditions are as follows:

• Production of rhizoids for water absorption.
• Conservation of water.
• Absorption of CO₂.
• Heterogamy (Formation of different gametes, male and female).
• Protection of reproductive cells.
• Formation of embryo.

Q.5: What are Tracheophytes? Name the groups of Tracheophytes?

Ans: Tracheophyta division consists of vascular plants. They are terrestrial in nature. This division is divided into five sub-divisions.

• Sub-division - Psilopsida (Psilopsids)
• Sub-division - Lycopsida (Club mosses)
• Sub-division - Sphenopsida (Horse tail)
• Sub-division - Pteropsida (Ferns)
• Sub-division - Spermospsida (Seed plants)

The plants of this division have four fundamental adaptations for terrestrial habitat. These are as follows:

• Around the reproductive organs, a protective layer of sterile jacket cells is present.
• Multi-cellular embryos remain in the female reproductive organs, archegonia.
• On the aerial parts of the plant, cuticle layer is present.
• Xylem is present for conduction of water.

Q.6: Write a note on Evolution of Leaf?

Ans: EVOLUTION OF LEAF: Leaf is a very important organ of plant because it takes part in photosynthesis. They are evolved from the primitive vascular plants. To trace the origin of leaf we have to study the types of leaves. In vascular plants there are two types of leaves.

• One is simple, small, and scale-like. It contains only one vein, so it is called a single-veined leaf.
• Another type is a multi-veined leaf because it contains many veins. It is larger in size with distinct lamina.

Origin Of Single-Veined Leaf: In the case of single-veined leaves, the fossils provide no proper evidence. It is assumed that it originated from a leaf-less branch of primitive vascular plants by the reduction in size and gradually this leaf-less branch has changed into a single-veined leaf. This type of leaf was developed in club-moss and horse-tail plants.

Origin Of Many-Veined Leaf: In the case of many-veined leaves, it is assumed that their production started much later. These are the modified form of forked-branches in primitive land plants. In their evolution, the first step was the union of forked-branches and continuation of growth in one direction, so they were changed into a flat body. The second step was the formation of green cells between these branches and vascular tissues.

They were filled up by photosynthetic tissues, and they were ultimately changed into leaf-like structures.

Q.7: Describe the structure and reproduction of Rhynia?

Ans: Rhynia is the most primitive known plant. It was lived about 40 million years ago and now it is preserved as a fossil.

The plant body of Rhynia consisted of two parts, an underground rhizome and an aerial stem. The aerial stem was 20-50 centimeters in height and 1-6 millimeters in diameter.

The rhizome was creeping and dichotomously branched. From its lower side rhizoids were produced which were to absorb water and salts from the soil. True roots were absent. The aerial stem was erect and dichotomously branched. The branches were green due to the presence of chlorophyll; they had the function of photosynthesis. The branches were leafless.

Internal Structure Of Rhynia: The internal structure of the branches of Rhynia shows the following parts:

• Epidermis: It is the outermost layer having stomata.
• Cortex: Below the epidermis, the cortex region is present.
• Vascular Tissues: These are present in the center, surrounded by the cortex. Xylem is in the center, which is surrounded by phloem.

Reproduction: Rhynia plant was a sporophyte. From the branches of the aerial stem, sporangia were produced. They were oval-shaped or cylindrical. They produced spores. The spores were responsible for developing into a gametophyte of Rhynia, but it could not be preserved; thus, its details are still unknown.

Q.8: Describe the Sporophytic Stage in the life cycle of Selaginella (Lycopsida)?

Ans: Sporophytic Stage Of Selaginella: In this stage, the plant reproduces by the asexual method. Selaginella plant is heterosporous, i.e., it produces two types of spores, microspores, and megaspores.

At the time of reproduction are developed cone-like bodies at the apex of fertile shoot, called strobili. In the strobili, the leaf-like structures are called sporophylls. These sporophylls are of two types: microsporophyll’s and megasporophylls. A single strobilus bears microsporophyll’s at the upper side and megasporophylls at the lower side. In the axil of microsporophyll’s microsporangia and in the axil of megasporophylls megasporangia are developed.

In each microsporangium many microspores are produced. The microspores are changed into male gametophyte.

In each megasporangium, four megaspores are produced, which develop into female gametophyte.

Q.9: Describe the Gametophytic Stage in the life cycle of Selaginella (Lycopsida)?

Ans: Gametophytic Stage: In Selaginella, two types of gametophytes are present. The male gametophyte and female gametophyte. In male gametophyte, male gametes are produced. In female gametophyte, small flask-shaped archegonia are developed. In each archegonium, an egg cell (female gamete) is present.

Fertilization: The male gametes enter the archegonia, each male gamete fuses with the egg cell and forms oospore (zygote). The oospore produces an embryo, which develops into a new Selaginella plant.

Q.10: Write a note on Evolution of Seed?

Ans: There is evolution of seed in plants. In Selaginella, two types of spores are produced, microspores, smaller in size, and megaspores, larger in size. This process is called heterospory. The microspores develop into male gametophytes, and megaspores develop into female gametophyte.

The sporangia in Selaginella are of two kinds. These sporangia are protected by scale-like structures. Similarly, the sporangia of club mosses, horsetails, and ferns are also protected. This is the process of evolution. In Carboniferous era, some fern-like plants were produced, and their sporangia were surrounded by some special branch-like structures. During evolution, branch-like structures were modified into an envelope or integument around the sporangia.

In seed plants, there is a different condition. Unlike other green plants, in the seed plants, the megaspores remain inside the sporangia, which are covered by protective covering called integuments. The megaspores develop into female gametophyte. This gametophyte is protected by integuments.

There are three steps in the evolution of seeds:

• Origin of Heterospory i.e., Formation of two types of spores
• Development of integument for the protection of megasporangia
• Retention of the mature megaspores in the sporangia to develop female gametophyte

Q.11: Write down the important characters of Pteropsida (Ferns)?

Ans: Important Characters of Pteropsida (Ferns): The important characters of these plants are as follows:

• The plant body consists of roots, stem, and leaves. It is sporophytic in nature.
• The leaves are larger in size, called megaphylls or fronds.
• The stem is subterranean rhizome, but in some ferns, it is aerial and erect.
• Each leaf consists of two parts, petiole and blade. The petiole is covered with hairs, called ramenta.
• The blade is either simple e.g., Ophioglossum or pinnately compound i.e., divided into many small leaflets, called pinnae and pinnules.

Q.12: Describe briefly the life cycle of Fern?

Ans: The life cycle of Fern is completed in two stages:

• Sporophytic stage
• Gametophytic stage

It shows alternation of generations.

Sporophytic Stage: It is an asexual stage. In this stage, the mature leaves (sporophylls) produce small reddish brown bodies, called Sori. Sori are the group of sporangia.

Each sporangium consists of two parts, a stalk, called sporangiophore, and a capsule. Capsule is biconvex oval shaped structure. The wall of capsule has two parts, a thin-walled part, called stomium, and a thick-walled part, known as annulus.

The sporangium spore mother cells are produced, which divide by meiosis and produce haploid spores. When spores are mature, the sporangial wall ruptures at stomium and spores are liberated out. Each spore germinates and develops into gametophyte, which is also called Prothallus.

Gametophytic Stage: The spore germinates into a heart-shaped body, called prothallus. It is the gametophyte.

The prothallus is a gametophyte. It produces two different types of reproductive organs, male and female. The male organs are called antheridia, which are developed towards the rhizoid sand, and female organs are known as archegonia, which are borne in the central region of the prothallus.

Each antheridium produces male gametes. The archegonia are flask-shaped. Each archegonium produces an egg cell (female gamete).

Fertilization: At the time of fertilization, many male gametes move towards archegonia. Many male gametes enter the archegonium, but one fuses to form oospore.

The oospore germinates into a young sporophyte, which grows into a new fern plant.

Q.13: Describe the staminate cone of Pinus?

Ans: STAMINATE CONE: (MALE CONE)

• It is a small cone. Its size is less than 3cm.
• Each cone consists of a central axis. From i
• ts both sides spiral-shaped scales are developed, called microsporophylls.
• On the inner side of each scale, two microsporangia are present.
• In each microsporangium, numerous microspores are produced by meiosis.
• Each microspore consists of two layers; the outer layer is called exine, and the inner one is known as intine.

Q.14: Describe the ovulate cone of Pinus?

Ans: OVULATE CONE: (FEMALE CONE)

• It consists of a central axis. Round the axis many thin, brownish scales are produced, which are arranged in spiral manner. They are called carpellary scales or bract scales.
• At the upper side of each carpellary scale a large, hard, and woody scale is present, known as ovuliferous scale. It produces two ovules on the inner side.
• Each ovule consists of a central body, called nucleus or megasporangium. In the nucleus or megasporangium, a megaspore is present. Megaspore takes part in the formation of female gametophyte.

Q.15: Write the different parts of Flower?

Ans: FLORAL ORGANS: A flower consists of four types of floral organs. These parts are arranged in whorls in a definite order. These organs are as follows:

• Calyx:

  • This is the first and outermost whorl, composed of small, leafy structures, called sepals. They are usually green, but sometimes they are highly colored, called petaloid. Their function is to protect the inner parts of the flower. When the sepals are free, it is called polysepalous, and when they are united together, it is termed as gamosepalous. Sometimes the sepals are modified into hairs and called pappus, e.g., Composite family.

• Corolla:

• This is the second whorl and is composed of expanded and brightly colored structures, called petals. They may also have glands which produce juicy substances. They attract the insects for pollination.

If the petals are free, it is called poly-petalous, and if petals are fused together, it is known as gamo-petalous. In some flowers sepals and petals do not differ in shape and colour and their members are alike to form a single part of a flower; it is termed as perianth.

Androecium:

• It is composed of the male reproductive organs, the stamens. Each stamen consists of three parts: filament, anther, and connective.
• Filament is the stalk, and anther is the expanded head borne at the tip. Each anther has two lobes, and each lobe produces two chambers called pollen sacs. Within each pollen sac, the pollen grains are present, which are the male reproductive bodies.

Gynoecium:

• It is the female whorl of the flower and is composed of Carpels.

Apocarpous Or Syncarpous:

• When many carpels are present in a pistil and they are free, it is termed as apocarpous, and when the carpels unite together, it is known as syncarpous.

Parts Of A Pistil:

• Each pistil consists of three parts: stigma, style, and ovary. Stigma is the uppermost part, which receives the pollen grains, style is the middle elongated stalk, and ovary is the basal swollen part.
• The ovary has one or more chambers inside. Each chamber contains one to many ovules. The ovary having one chamber is called unilocular, and when many chambers are present, it is known as multilocular. The ovules are attached to the wall of the ovary by small structures called placenta.

Q.16: What is Placentation?

Ans: PLACENTATION:

• Ovules are attached to the inner wall of ovary by special tissues, called placenta. The ovule is attached to the placenta by a short stalk, the funiculus. The arrangement of placenta within the ovary is known as placentation. There are several types of placentation: basal, marginal, central, axile, parietal.

Q.17: Describe the structure of ovule?

Ans: STRUCTURE OF OVULE:

• The ovule is enclosed in two outer coats, called integuments. At one end of the ovule, a small pore is present, the micropyle. Within the integuments, nucleus is present. It is considered as megasporangium. It contains egg sac or embryo sac. At the micropylar end, three cells are present; one of these cells is the egg cell or ovum, and other two cells are called synergids. At the...

Q.18: Describe the Floral Characters of Family Rosaceae?

Ans: FLORAL CHARACTERS:

Inflorescence:

• Solitary, racemose or cymose.

Flower:

• Pedicellate, complete, bisexual, actinomorphic, hypogynous or perigynous, usually showy and scented, pentamerous.

Calyx:

• Sepals 5, gamosepalous (fused) or polysepalous (free), aestivation valvate. Calyx tube is present.

Corolla:

• Petals 5 or numerous in multiple of five, polypetalous, imbricate aestivation, rosaceous, large, showy of various colours.

Androecium:

• Stamens numerous, polyandrous, usually borne in many cycles of 5, anthers small, bilocular.

Gynoecium:

• Carpels 1-5 or many, apocarpous or united, enclosed in calyx tube, superior ovary, sometimes inferior ovary, one or two ovules in each carpel. Style short, stigma linear, capitate.

Placentation:

• Basal in apocarpous or monocarpellary flower, Axile in syncarpous or multicarpellary flower.

Fruit:

• Pome or drupe, or achene follicle.

Seed:

• Non-endospermic.

Floral Formula:

• ⊕, ⊍, K₅, C₅-∞, A∞, G₁-5 or ∞ or G₅

Q.19: Describe the economic importance of Family Rosaceae?

Ans: ECONOMIC IMPORTANCE OF FAMILY ROSACEAE:

• Some plants produce edible fruits, such as:

  • Apple (Pyrus malus), Apple
  • Pear (Pyrus communis), Naspati
  • Peach (Prunus persica), Aru
  • Almond (Prunus amygdalus), Badam
  • Apricot (Prunus arminiaca), Khubani
  • Strawberry (Fragaria)
  • Rose (Rosa indica), Gulab

• Many plants are grown for ornamental purposes, e.g. Rose (Rosa indica), Spiraecea, Sorbus, Potentilla etc.

• Scents are obtained from Rose and other plants.

• The petals of Rose are used to manufacture a laxative, called gulkand.

• The branches of some trees are used as walking sticks.

• The extract of Rose (Ark-Gulab) is used in eye diseases and for other purposes.

• The wood of Pear (Pyrus pestia) is used to make tobacco pipes.

Q.20: Describe the Floral Characters of Family Solanaceae?

Ans: FLORAL CHARACTERS:

• Inflorescence:
  An axillary cyme.

• Flower:
  Pedicellate, bisexual, actinomorphic, hypogynous, pentamerous, bracteate or ebracteate.

• Calyx:
  5 sepals, gamosepalous, aestivation valvate, persistent, hairy, campanulate (bell-shaped), green.

• Corolla:
  5 petals, gamopetalous, aestivation valvate, rotate tubular, infundibuliform (funnel-shaped) or tubular.

• Androecium:
  5 stamens, polyandrous, epipetalous (attached with petals), alternate with corolla lobes. Usually of unequal size.

• Gynoecium:
  Bicarpellary; syncarpous, pistil one, ovary obliquely placed, usually 2-chambered, becoming two or many-chambered by false septa, many ovules, Placentation - axile.

• Fruit:
  Capsule (Datura), Berry (Solanum nigrum)

• Formula:
  ⊕, ⊍, K5, C5, A5, G2

Q.21: Describe the economic importance of Family Solanaceae?

Ans:
The economic importance of the family Solanaceae is as follows:

• Some plants of the family are used as vegetables. e.g. Potato (Solanum tuberosum), Tomato (Lycopersicum esculentum), Brinjal (S. melongena).
• Some plants are of medicinal value, such as the roots of Solanum xanthocarpum are used in cough, asthma. The leaves of Datura metal are used in the treatment of asthma.
• Tobacco (Nicotiana tabacum) is narcotic in nature. It is a source of nicotine.
• Red pepper or chilli is used as Condiment.
• Some plants are used for Ornamental purposes e.g. Petunia, Queen of night (Jassamine) is grown in the gardens, its flowers are scented at night.

Some Important Plants:

• Solanum tuberosum (Potato)
• Solanum melongena (Brinjal)

Q.22: Describe the important Floral Characters of Family Mimosaceae?

Ans: FLORAL CHARACTERS:

• Inflorescence:
  Racemose raceme.

• Flower:
  Pedicellate or sessile, bracteate, complete, bisexual, actinomorphic, hypogynous.

• Calyx:
  Usually 5 sepals, gamosepalous, rarely polysepalous, valvate aestivation, in some plants aestivation is imbricate, green.

• Corolla:

  • 5 petals, gamopetalous, rarely polypetalous, valvate aestivation, corolla lobed.

  Androecium:

  • 5 to numerous, polyandrous, united at the base.

  Gynoecium:

  • Monocarpellary, ovary superior, unilocular, many ovules, style long, Placentation - Marginal.

  Fruit:

• Legume or Lomentum.

Q.23: What is the economic importance of Family Mimosaceae?

Ans: ECONOMIC IMPORTANCE OF FAMILY MIMOSACEAE:

• Many trees provide wood for fuel or furniture, e.g. Acacia, Xylia, and Albizzia.
• Some plants yield gum, e.g., Acacia senegal and Acacia nilotica.
• A dye called Katha is obtained from Acacia catechu.
• The leaves of Acacia nilotica are used as a blood purifier.
• Some plants are of ornamental value, e.g., Mimosa pudica, Acacia melanoxylon.

Important Plants:

• Acacia arabica (Babool)
• Acacia catechu (Katha)
• Mimosa pudica (Touch-me-not)
• Albizzia lebbek (Sins - Timber plant)
• Acacia nilotica (Gum tree, Kikar)
• Prosopis glandulosa (Prosopis)

Q.24: What are the Floral Characters of Family Caesalpiniaceae?

Ans: FLORAL CHARACTERS:

• Inflorescence: Racemose raceme or spike.
• Flower: Pedicellate, bracteate, complete, bisexual, zygomorphic, rarely actinomorphic, perigynous or hypogynous, pentamerous.
• Calyx: 5 sepals, polysepalous or gamosepalous imbricate or valvate.
• Corolla: 5 petals, polypetalous, imbricate, with the lower petal being the innermost.
• Androecium: Few or 10 stamens, polyandrous; filaments are of unequal size, sometimes staminodes (small stamens) are present.
• Gynoecium: Monocarpellary, ovary superior, unilocular, ovules 1–many along the margin, placentation - marginal.

Floral formula: ✝ K₅ or K₅, C₅, A₁₀, G₁

Q.25: What is the economic importance of Family Caesalpiniaceae?

Ans: ECONOMIC IMPORTANCE OF FAMILY CAESALPINIACEAE:

• Some plants are used as food, such as the leaves and buds of Bauhinia variegata (Kachnar) are used as vegetables.
• The leaves of Tamarindus indica contain tartaric acid. These are edible.
• The leaves of Cassia alata are used in skin diseases and for the cure of ringworm.
• Cassia senna yields a drug, senna. It is used in laxative medicines.
• Oil from the seeds of Cymonera is used for skin diseases.
• Some plants are cultivated for ornamental purposes, e.g. Bauhinia variegata (Kachnar); Cassia fistula (Amaltas); Parkinsonia sp.
• A dye haematoxylon is obtained from Haematoxylon species.

Important Plants Of The Family:

• Cassia fistula (Amaltas)
• Bauhinia variegata (Kachnar)
• Parkinsonia sp. (Vilayati Kikar)
• Tamarindus indica (Tamarind - Imli)
• Haematoxylon sp.
• Poinciana regia (Flame of Forest - Gul-e-Mohar)

Q.26: Describe the Floral Characters of Family Fabaceae?

Ans: FLORAL CHARACTERS:

• Inflorescence: Mostly racemose or solitary axillary.
• Flower: Pedicellate, complete, bisexual, zygomorphic, perigynous or hypogynous, pentamerous.
• Calyx: 5 sepals, gamosepalous, valvate aestivation, green, hairy.
• Corolla: 5 petals, polypetalous, petals are of different sizes. The lowest petal is the largest one, called vexillum or standard; two side petals are wings or allae, and the two innermost petals fuse together to form a boat-shaped structure, known as keel or carina. This arrangement is called vexillary; it is called papilionaceous flower.
• Androecium: 10 stamens, diadelphous (found in two groups), nine stamens are united, and one is free (9) + 1.
• Gynoecium: Monocarpellary (one carpel), ovary superior, consists of one chamber (unilocular), many ovules are present along the margin.
• Placentation: Marginal
• Fruit: Legume
• Seed: Non-endospermic.

Floral Formula:
†, K_5, G_(1+2+(2)), A_(9)+1, G_1

Q.27: What is the economic importance of Family Fabaceae?

Ans: ECONOMIC IMPORTANCE:

• Some plants of this family are used as food material, such as Pea, Gram, Bean, Pulses, Groundnut, etc.
• From groundnut oil is obtained, which is used to manufacture banaspati ghee.
• Some plants are used as vegetables, e.g., soybean, pea.
• Some plants are used by animals as their food.
• From some plants, dyes are obtained, such as Indigofera (Neel).
• Some plants are of ornamental value, e.g., Clitoria.
• From Sisso tree, wood is obtained, which is used to make furniture.

Important Plants Of The Family:

• Pisum sativum (Pea)
• Lathyrus odoratus (Sweet pea)

Q.28: Describe the Floral Characters of Family Poaceae?

Ans: FLORAL CHARACTERS OF THE FAMILY:

• Inflorescence:
  Spike or spikelet. In spikelet, two bracts are present at the lower side, the outer or lower bract is called first glume, and the upper or inner bract is known as the second glume. Each small flower also has two bracts; the outer bract is lemma, and the inner bract is called palea (The lemma is also called superior palea, and the other one is known as inferior palea).

• Flower:
  Sessile, bisexual, zygomorphic, hypogynous. Lemma and palea form the protective covering around the flower.

• Perianth:
  It consists of two lodicules, free, valvate.

• Androecium:
  Stamens 3, polyandrous (free), long filaments.

• Gynoecium:
  Carpels 3 but only one functional, ovary superior, unilocular (one-chamber), one basal ovule placentation - Basal, style two, stigma feathery.

Floral Formula:
†, P₂ lodicules, A₃, G₃ or G₁

Q.29: What is the economic Importance of Family Poaceae?

Ans: ECONOMIC IMPORTANCE OF THE FAMILY:

• Many plants of this family are used as food material, such as Maize, Rice, Wheat, Oat, etc.
• Some plants are used by animals as their food.
• Bamboo and other plants are used as building material.
• From sugarcane, sugar is prepared.
• From Bamboo and other plants, paper is manufactured.
• From some grasses, oils and medicines are obtained.

Q.30: Distinguish between:

Ans: SEXUAL & ASEXUAL REPRODUCTION:

Sexual reproduction	Asexual reproduction
In sexual reproduction, formation of two different kinds of reproductive bodies are produced, male gametes and female gametes.	In asexual reproduction, usually the same type of bodies are formed, called Spores. (In rare cases, spores may be of two types).
The male and female gametes fuse together; this process is called fertilization.	There is no fertilization process.
By the fusion of gametes, a zygote is formed.	There is no formation of zygote.

Important Plants Of The Family:

• Triticum (Wheat)
• Zea-mays (Maize)
• Oryza Sativa (Rice)
• Saccharum Officinarum (Sugar-cane)
• Bambusa (Bamboo)

ISOMORPHIC & HETEROMORPHIC ALTERNATION OF GENERATION:

Isomorphic Alternation Of Generation	Heteromorphic Alternation Of Generation
In some plants, the life cycle is completed in two stages, sporophytic stage (asexual stage) and gametophytic stage (sexual stage). Both plants of two stages are similar in morphology; it is called isomorphic alternation of generations.	In some plants, the life cycle is also completed in two stages, sporophytic stage and gametophytic stage, but the plants of two stages are different in morphology; it is known as heteromorphic alternation of generations.
E.g., Ulva, Dictyota.	E.g., Marchantia Sunflower.

SPOROPHYTE & GAMETOPHYTE:

Sporophyte	Gametophyte
Sporophyte is the plant which shows asexual stage.	Gametophyte is the plant which shows sexual stage.
It produces spores, which may be similar or, in few cases, of different types.	It produces gametes, which are of two types, male and female.
There is no fusion of spores; each spore directly develops into a new plant or gametophytic stage.	The male and female gametes fuse together to form zygote. The zygote develops into a new plant or sporophytic stage.

XYLEM & PHLOEM:

Xylem	Phloem
It is a complex tissue which helps in the conduction of water from roots to the upper.	Phloem is also a complex tissue which helps in the translocation of food from one part to another part in the body of plants.
The flow of water in xylem occurs only in one direction i.e., from roots to the upper region, up to the leaves.	The flow of food in the xylem occurs in both directions i.e., from the upper region to the lower region or from lower to upper region.
Xylem consists of four different types of tissues:	Phloem consists of four different types of tissues:
- Tracheids	- Sieve tubes
- Vessels or Tracheae	- Companion cells
- Wood parenchyma	- Phloem parenchyma, bast parenchyma.
- Wood fibers	- Phloem fibres or bast fibres.

MALE (STAMINATE) & FEMALE (OVULATE) CONE OF PINUS:

Male cone of pinus (Staminate cone)	Female cone of pinus (Ovulate cone)
It is a small cone. Its size is less than 3 cm.	It is a large cone. Its size is more than 3cm.
Each cone consists of a central axis.	It also consists of a central axis. From its sides, scales arise, which are of two types:
VESSELS & SIEVE TUBES: Vessels Sieve tubes These are elongated tube-like cells. They are thick-walled. These are also long tube-like but thin-walled cells. They are dead cells. They are living cells. They do not have transverse walls. They do not have pores. They have transverse walls which contain pores, so they are called sieve tubes. They help in the movement of water and dissolved minerals. They receive prepared food from leaves and supply it to the other parts. They also provide strength and rigidity. They do not provide strength and rigidity. GYNOECIUM OF ROSACEAE & GYNOECIUM OF SOLANACEAE: Gynoecium of Rosaceae Gynoecium of Solanaceae Gynoecium of Rosaceae consists of 5 to many carpels mostly. Gynoecium of Solanaceae is bicarpellary, i.e., consists of two carpels. It is mostly apocarpous i.e., free carpels; in rare cases, it is syncarpous. It is syncarpous, i.e., carpels are united. The ovary is unilocular generally. The ovary is bilocular or sometimes tetralocular. Ovary is ½ superior or inferior. Ovary is superior. Placentation is basal, rarely axile. Placentation is axile. ALGAE & PLANTS: Algae Plants These are simple plant-like organisms, their body is called thallus, which cannot be divided into root, stem, and leaves. These are well-developed organisms, their body is divided into root, stem, and leaves. These are water-living. These are water-living or terrestrial. They are non-vascular. They are vascular or sometimes non-vascular. They are non-flowering and non-seeded. Higher plants produce flowers and seeds. BRYOPHYTA & TRACHEOPHYTA: Bryophyta Tracheophyta These are simple plants without vascular tissues. These are advanced plants with vascular tissues. HOMOSPORY & HETEROSPORY: Homospory Heterospory The process in which similar types of spores are produced is called homospory. The process in which two different types of spores are produced is called heterospory. These are microspores and megaspores. In homosporous plants, only one kind of gametophyte produces male and female organs. In heterosporous plants, two different kinds of male and female gametophytes are produced. They produce one type of sporangium. They produce two types of sporangia. Homospory does not involve in the evolution of seed. Heterospory leads to the evolution of seeds.	- Thin brownish scales, the carpellary scales or bract scales.

Kingdom Fungi

 Biology XI Notes

Kingdom Fungi - Short Questions Answers

Chapter # 08
Short Questions Answers
Section III - Biodiversity

Kingdom Fungi

Q.1: Describe the structure of the body of Fungi?

Ans: Structure of the Body of Fungi:

• The fungi have a very simple body. In the majority of fungi, the body consists of a network of branched thread-like structures, called the Hyphae. When the hyphae form a mass, it is known as mycelium.

• The mycelium is of two types:

  • Coenocytic Mycelium:
    In Zygomycota, the mycelium is unseptate and multinucleate; it is called coenocytic mycelium. The septa are only formed at the time of reproduction.
  • Septate Mycelium:
    In Ascomycetes and Basidiomycetes, the mycelium is septate and hyphae are divided into cells. The cells may be uninucleate or multinucleate.

• The cells of mycelium are filled up with colorless cytoplasm, which contains nuclei and vacuoles. The food is stored in the form of glycogen or oil; starch is absent.

• In some fungi, mycelium is not present. They have a single-celled structure, e.g., Yeast. The cell wall of mycelium does not consist of true cellulose. It is composed of Chitin or Fungal cellulose.

(Fig. 8-1: Types of Hyphae of Fungi - Illustration showing Septate Mycelium and Coenocytic Mycelium)

Q.2: Describe Saprophytic and Parasitic nutrition of Fungi?

Ans:
Saprophytic Fungi: (Saprotrophs)
These fungi obtain their food energy from dead organic matter. They secrete out digestive enzymes, which digest the organic matter, and then the organic molecules are absorbed by fungi by the help of modified hyphae, called rhizoids. These fungi are the decomposers. They particularly decompose cellulose and lignin, present in plant cell walls.

Parasitic Fungi:
The parasites depend upon other living plants and animals. They cause many diseases in plants, animals, and human beings. When the parasitic fungi grow on the external surface of the host body, they are called ectoparasites, and when they live inside the host body, they are termed as endoparasites.

Q.2 (continued): Parasitic fungi absorb their food from other organisms by the help of special structures, called haustoria. Parasitic fungi are of three types:

• Obligate Parasite:
  These fungi obtain their food completely from the host body. They cannot grow on a culture medium. e.g., Rust fungi, Mildews.

• Facultative Parasites:
  They grow on their host as well as on artificial culture medium.

• Predator Fungi:
  Some fungi are predators i.e., they are carnivores and obtain their food from some animal bodies. For example, oyster mushroom (Pleurotus ostreatus) paralyzes the nematodes and takes nitrogenous nutrients from their body. Some species of Arthrobotrys also obtain their food from nematodes.

Q.3: What are the symbiotic fungi?

Ans: Symbiotic Fungi:
Some fungi form an association with other living organisms, in which both the organisms are mutually benefited. This type of association is called symbiosis and fungi are called Symbiotic fungi.

Symbiotic fungi are of two types:

• Lichens:
  • It is a very important group of algae and fungi which live together and form a beneficial type of association, called symbiosis. Both are useful to each other.
  • In lichens, fungi absorb water and salts and supply them to algae, while algae manufacture food material; in this way, both form a useful relationship. They cannot survive without each other.
  • Lichens are ecologically very important.
  •  They are bioindicators of air pollution.

(Fig. 8-2: (A-E) Lichens - Various Types of Lichens: (A) Crustose; (B) Foliose; (C) Fruticose (erect); (D) Fruticose (pendant); (E) Basidiolichen)

• Mycorrhizal Fungi:
  Some fungi form an association with the roots of higher plants. This association is mutualism, in which both organisms live together on a mutual basis. Both get benefits.

The hyphae of fungi help in the absorption of important substances, like phosphorus, zinc, copper, and other nutrients. The plant gets all these substances, and as a result of which, the plant supplies organic compounds to the fungus. In this way, fungi and higher plants live together.

There are two types of mycorrhizal fungi:

(Fig. 8-3: Types of Mycorrhiza)

Q.4: Describe different methods of Asexual Reproduction of Fungi?

Ans: ASEXUAL REPRODUCTION:
Asexual reproduction takes place by the following methods:

• Fragmentation:
  In this process, the hyphae divide into many small pieces, called fragments. Each fragment develops into a new mycelium of fungus.

• Budding:
  In yeast, small bodies are produced from the cells, called buds. These buds are separated from parent cells and grow into new fungi by simple cell division.

• Spore Formation:
  It is a common method of reproduction. The spores are produced in special reproductive organs, called sporangia. These spores are haploid and without flagella (non-motile). These spores are dispersed to other places, and during favorable conditions, germinate into new mycelium of fungi.

• Conidia Formation:
  These are special asexual spores, produced externally on the particular branches, called conidiophores. On these conidiophores, these spores are formed in chain-like manner. These spores are called conidia. The conidia are dispersed by wind and germinate into new fungi during favorable conditions.

Q.5: Describe the Sexual Reproduction in Fungi?

Ans: SEXUAL REPRODUCTION:
Sexual reproduction takes place in all fungi except Deuteromycetes. In this process, gametes are produced, which are either morphologically similar, called isogametes, or they are different, known as heterogametes. In such cases, the male organs are antheridia and female are oogonia. When the protoplasts from the two opposite (organs) are brought in contact, it is called plasmogamy. When the fusion of two nuclei occurs through...

Q.6: What is the classification of Fungi?

Ans: CLASSIFICATION OF FUNGI:
Fungi are classified into four divisions or phyla:

• Zygomycota
• Ascomycota
• Basidiomycota
• Deuteromycota

Q.7: Describe the characters of division Zygomycota of Fungi?

Ans: DIVISION - ZYGOMYCOTA:

• Zygomycota is the smallest group of fungi, including about 600 species. In this group, bread molds and other saprophytic fungi are present.
• These fungi have coenocytic mycelium, i.e., it is multinucleate and unseptate. The septa are formed only at the formation of sporangia or gametangia.
• In these fungi, there is a complete absence of motile cells.
• Asexual reproduction takes place by spores produced in sporangia.
• Sexual reproduction takes place by the fusion of isogametes; due to which zygospores are formed, so the group is called zygomycota.

Q.8: Describe the Asexual Reproduction of Zygomycota (Rhizopus)?

Ans: ASEXUAL REPRODUCTION:
It takes place during favorable conditions. At the time of reproduction, many erect branches arise from the mycelium, called sporangiophores. At the tip of each sporangiophore, a rounded body is formed, into which the cytoplasm, nuclei, and oil globules are transferred from the mycelium. The oil globules arrange themselves to form a layer, and the rounded body divides into two parts. The upper larger part is called sporangium, while the smaller lower part is known as columella.

In the sporangium, the cytoplasm is very dense, and it contains many nuclei; in columella, the cytoplasm is thin, without any nucleus.

Q.9: Describe the Sexual Reproduction of Zygomycota (Rhizopus)?

Ans: SEXUAL REPRODUCTION:
It takes place during unfavorable conditions. At the time of sexual reproduction, two hyphae of opposite strains (+ and -) come parallel to each other. Each hypha produces an outgrowth, the papilla, which divides into two cells. The lower cell is called basal cell or suspensor cell. The upper cell is called gametangium. In each gametangium, a gamete is formed. These gametes are externally similar, so they are known as isogametes.

The isogametes are fused together, this process is called conjugation. As a result of conjugation, a zygospore is formed.

Germination Of Zygospore:
The zygospore produces a branch, called sporangiophore. At the tip of sporangiophore, a sporangium is produced. The nucleus and reserved cytoplasm of zygospore are migrated into the sporangium. The nucleus divides by meiosis into many nuclei, then cytoplasm also divides into many pieces, each piece of cytoplasm surrounds the nucleus; in this way, many spores are formed.

After the maturation of spores, the wall of sporangium ruptures and all spores become free. They remain in air and by the availability of organic food substance, they germinate into new mycelium of fungus.

Q.10: What are the characters of division Ascomycota of Fungi?

Ans: DIVISION - ASCOMYCOTA:
It is the second division of fungi. This is a group of advanced fungi. In Ascomycota Yeasts, common molds, morals, truffles are included. Many plant pathogens are also in this group, such as powdery mildew etc.

Characters:

• Ascomycota is the sub-division of fungi. It is a Latin word, derived from two words ascos means bladder and mykos means fungi, so they are called sac-fungi.
• In this group both saprophytic and parasitic fungi are included. The saprophytic fungi depend upon dead organic substances. The parasitic fungi obtain their food from other plants and cause many diseases, such as leaf curl of peach, apple scab, and chestnut blight etc.
• According to the structure, different types of fungi are present in this group. Yeasts are unicellular fungi. In advanced fungi, the body is called mycelium. It is branched and septate. The mycelium consists of many hyphae. Each cell of hypha is uninucleate or multinucleate.

Q.11: Describe the Asexual Reproduction of Division Ascomycota of Fungi?

Ans: ASEXUAL REPRODUCTION:
In ascomycota asexual reproduction takes place by different methods, such as conidia, budding, fission, etc., but conidia formation is the most common method.

Conidia Formation:
It is the most common method of reproduction. They are important asexual bodies. They are produced on branches, called conidiophores. They are formed in a chain-like manner.

These conidia are dispersed to different places and during favorable conditions, these conidia develop into new mycelium of fungus.

Q.12: Describe the Sexual Reproduction of Division Ascomycota?

Ans: SEXUAL REPRODUCTION:
In Ascomycota, sexual reproduction takes place by the formation of male and female reproductive organs. The male organs are called antheridia and female are called ascogonia. They are usually developed at the apex of hyphae.

Q.13: What is Ascocorp? Describe different kinds of Ascocorp of Fungi?

Ans: FRUITING BODY: (ASCOCORP)
In Ascomycota a protective fruiting body is developed, called ascocarp. In the ascocarp asci are present.

The diploid zygote nucleus divides by meiosis into eight nuclei. These are surrounded by pieces of cytoplasm and change into ascospore pores. The cell in which ascospores are formed is called ascus. Many asci are formed in this manner.

There are three types of ascocarps.

1. Apothecium:
   It is a cup-shaped, saucer or disc-shaped ascocarp. It is open and its cavity is lined with a single row of asci which are freely exposed. Apothecium is formed in Morchella, Peziza.

2. Perithecium:
   It is a flask-shaped ascocarp. The asci are present in the ascocarp. At the apex of perithecium, a pore or opening is present, called ostiole. Perithecium is found in Erysiphe.

3. Cleistothecium:
   It is a rounded and completely closed fruit body without any ostiole. The asci are arranged in the inner side, and the ascospores are liberated out by the rupturing of the wall of ascus and cleistothecium or by the decay of fruit body. It is found in yeast, Aspergillus.

Q.14: Describe the Structure of Saccharomyces (Yeast)?

Ans: SACCHAROMYCES (YEAST):
The yeast belongs to the class Ascomycetes of fungi. It consists of a single cell and mostly lives as a saprophyte on fruits, leaves, soil, and sugar materials.

Structure:
Yeast is a unicellular and microscopic fungus. Its cells are rounded, oval-shaped, or rod-shaped. Each cell is covered by an outer chitinous wall. In the cell, cytoplasm is present. In the center of the cell, nucleus is present, which contain

s a large vacuole, called nuclear vacuole.

Q.15: Describe the Asexual Reproduction of Yeast?

Ans: ASEXUAL REPRODUCTION:
Asexual reproduction is of two types:

1. Budding:
   In this process, smaller cells are produced from yeast cell.

2. Fission:
   In this process, one cell divides into two cells by a simple process.

Q.16: Describe the Sexual Reproduction of Yeast?

Ans: SEXUAL REPRODUCTION:
It takes place by the fusion of two cells. By the fusion of two cells, a barrel-shaped structure is formed, known as ascus. The zygote nucleus divides by meiosis and produces eight nuclei. The cytoplasm also divides, and each nucleus is surrounded by a piece of cytoplasm; it is called ascospore. In this manner, eight ascospores are developed. When the ascospores are mature, the wall of ascus ruptures, and they become free. They form new yeast cells.

Q.17: What is the importance of Yeast?

Ans: IMPORTANCE OF YEAST:
Positive Importance:

• Yeast is used in alcohol fermentation.
• It is used in beer formation.
• It is useful to prepare bakery products.
• Cryptococcus contains vitamins, in is used as food material.

Negative Importance:

• It spoils many foodstuffs, especially cheese and tomato.
• It causes many diseases, such as:
  • Yeast vaginitis causes a disease in women, called vaginal thrush.
  • Cryptococcus produces a disease of the central nervous system, called cryptococcosis.
  • Candida causes diseases of skin, nails, and lungs, known as moniliasis.

Q.18: Describe the Characters and Reproduction of Basidiomycota of Fungi?

Ans: CHARACTERS OF DIVISION - BASIDIOMYCOTA:
Basidiomycota is an advanced group of fungi. In this group, smut fungus, rust fungus, puff balls, bracket fungi, jelly fungi, bird’s nest fungi, and mushrooms are included.

Vegetative Structure:
The mycelium of basidiomycotina fungi is advanced; it is branched and septate. The cell wall is composed of chitin. The mycelium is intracellular or intercellular. Each cell contains cytoplasm and nucleus. The mycelium with uninucleate cells is called primary mycelium (prokaryotic mycelium), and with two nuclei is called secondary mycelium (dikaryotic mycelium).

Reproduction in Basidiomycota:
In Basidiomycetes, the sexual reproductive structure is called Basidium. Due to the name basidium, the class is called basidiomycetes.

The basidium is a club-shaped structure. In the basidium, two nuclei are migrated from the mycelium. The two nuclei are fused together in the basidium to form zygote. It is the only diploid cell in the life cycle.

After the formation of zygote meioses takes place, and it divides into four haploid nuclei. At the end of basidium, four stalks are produced, called sterigmata (singular: sterigma). The tip of sterigma becomes swollen, and each nucleus is migrated into swollen end; it results in the formation of four basidiospores. After maturation, the basidiospores are separated from sterigma. They can germinate during favorable conditions and develop into new mycelium of fungi.

Q.19: Describe the Characters of Deuteromycota (Fungi-Imperfecti)?

Ans: CHARACTERS OF DIVISION DEUTEROMYCOTA:

• It is an artificial group of fungi. In this class, all those fungi are included which do not have sexual reproduction.
• In this group, mostly fungi of ascomycetes or basidiomycetes are included. The mycelium is branched and septate. In the cells, cytoplasm and many nuclei are present.
• Reproduction usually takes place by conidia, but acervulus, synnema, or coremium are also formed as reproductive organs.

Genetic Recombination: Although sexual reproduction is absent in deuteromycetes, there is the process of genetic recombination. In this process, hyphae of different genetic types are fused together. From such fusion, certain hyphae arise, in which genetic recombination occurs, called parasexuality. In parasexuality, exchange of chromosome portions occurs between common hyphae. Genetic recombination is responsible for the production of pathogenic types of wheat rust.

Q.20: Describe the Economic importance of Fungi?

Ans: ECONOMIC IMPORTANCE OF FUNGI: Fungi do not possess chlorophyll, due to which they are unable to manufacture their food. They are either parasite or saprophyte organisms. Economically, they are useful and as well as harmful. Their importance is as follows:

Useful Importance:

Food

• Many mushrooms are used as food material in various countries of the world.
• Yeast is used in bakeries to prepare many items.
• Penicillium is used in the cheese industry.

Preparation of Acids and Alcohols:

• From Aspergillus, many acids are prepared, such as citric acid, gluconic acid, gallic acid, and Kojic acid, etc.
• Penicillium is used to obtain alcohol.
• From yeast, beer is synthesized.

Medicines:

• From many fungi, antibiotic medicines are obtained such as:
• From Penicillium, the world-famous antibiotic Penicillin is isolated. Other antibiotics like Citrin, Clavicin, and Notatin are also obtained.
• From other fungi, chloromycetin, neomycin, and terramycin are obtained.
• Yeast is used to prepare vitamin B.

Soil-Fertility:
Fungi decompose dead bodies of other living organisms due to which many compounds are added in the soil. It increases the fertility of soil.

Atmosphere Cleaners:
Fungi use dead bodies of plants and animals as their food, so they clean our world. They are called cleaners.

Harmful Importance:

Food Spoilage:
Many fungi are saprophytes. They destroy our foodstuff, such as Mucor, Rhizo pus, Aspergillus and Penicillium etc.

Plant Diseases:
Many fungi attack our crops and cause a heavy loss, for example:

• Rust and Smut fungi damage the wheat, maize, oat, and other plants.
• Phytophthora fungus causes Late-blight disease in potato and tomato.
• Albugo causes white-rust disease in Radish, Turnip, and Cauliflower.
• Downy-mildew and Powdery-mildews are the diseases of many plants which are produced by fungi.

Animal Diseases:
The fungi are also responsible for producing many diseases in man and other animals, such as:

• Penicillium causes Penicillosis disease in man and animals.
• Aspergillus produces Aspergillosis in man.
• In man, the disease of skin, mouth, and gums is called Moniliasis. It is caused by a fungus, Candida.
• The ring-worm fungi also cause diseases of hairs, nails, and skin in man.

Spoilage Of Leather And Paper Goods:
The fungi destroy our leather goods, such as suitcases, shoes, bags, etc. They also damage the fibers, paper, and wood.

Poisonous Mushrooms:
Many mushrooms are poisonous; they are harmful to man and may cause death, e.g., Death-stools and Toad-stools.

Q.21: Distinguish between the following:

Ans: Zygomycota and Ascomycota

Zygomycota	Ascomycota
This is the primitive class of Fungi, which contain unseptateand multinucleate mycelium i.e., coenocytic mycelium.	This is an advanced class of Fungi, which contain septate mycelium

	They are saprophyte in nature. They are saprophyte as well as parasites. Their asexual reproductive bodies are called spores, produced in sporangia. Their asexual reproductive bodies are mostly conidia, which are without sporangia. Sexual reproduction is isogamy i.e., fusion of two similar gametes. Sexual reproduction is oogamy, i.e., dissimilar gametes. They do not have any fruiting body. Fungi and Plants: Fungi Plants These are simple organisms having thread-like structures, their body is called mycelium. They are well-developed living organisms, their body consists of root, stem, and leaves. They do not contain chlorophyll, they are parasites or saprophytes i.e., heterotrophs. They contain chlorophyll i.e., they are autotrophs. They do not require sunlight and water. They require sunlight & water. They are non-flowering. Higher plants (angiosperms) produce flowers.