Chapter # 01 - Biology - XI
Short Questions Answers Section I - Introduction
Q.1: What is Biology?
Ans:
Biology is one of the natural sciences, which deals with the study of living organisms. It is known as the study of life. The word "biology" is derived from Greek words "Bios" meaning life and "Logos" meaning study or knowledge.
Formerly, living organisms were classified into two kingdoms:
Plant Kingdom:
In this kingdom, plants were included. The study of plants is called Botany.Animal Kingdom:
In this kingdom, animals were included. The study of animals is known as Zoology.
Q.2: Write a note on Five Kingdoms Classification?
Ans:
According to modern research, the old system of classification has been discarded. Now, all living organisms are classified into five kingdoms. This system was proposed by Robert Whittaker in 1969 and was later modified by two American biologists, L. Margulis and K. Schwartz.
Kingdom - Monera:
This kingdom includes all the prokaryotes. These are simple living organisms which do not contain a complete nucleus in their cells, e.g., Blue-green algae, Bacteria.Kingdom - Protoctista (Protista):
This kingdom includes three kinds of living organisms:Animal-like:
Unicellular protozoan organisms like Amoeba, Euglena.Plant-like:
Algae - simple water-living organisms that contain chlorophyll.Fungi-like:
Slime mold, water mold.
Kingdom - Fungi:
This kingdom includes multi-cellular, non-green thallophytes that have a very simple body called mycelium. They have a cell wall, and their body may be coenocytic (multinucleate). Due to the absence of chlorophyll, they cannot manufacture their own food, so they are either parasites or saprophytes, e.g., Agaricus (Mushroom), Yeast.Kingdom - Plantae:
This kingdom includes multi-cellular, eukaryotic organisms that have a complete nucleus in their cells. They usually contain chlorophyll and can manufacture their own food, e.g., Mustard, Sunflower, Apple.Kingdom - Animalia:
This kingdom includes multi-cellular eukaryotic organisms with a complete nucleus in their cells. They do not contain chlorophyll and have no cell wall, e.g., Hydra, Earthworm, insects, Frog, Birds, Fishes, Man.
Q.3: What are the major branches or fields of Specialization of biology?
Ans:
Some major branches or fields of specialization in biology are as follows:
Molecular Biology:
It is a modern branch of biology focusing on the structure and function of molecules that support biological processes in living organisms, such as nucleic acids, gene structure, proteins, and protein synthesis. It is the foundation of genetic engineering.Microbiology:
It deals with the study of micro-organisms, such as viruses, bacteria, and protozoans.Environment Biology:
This branch studies the environment and its impact on organisms.Marine Biology:
It focuses on organisms found in seawater or ocean water and examines their physical and chemical environmental characteristics.Fresh Water Biology:
This branch studies life found in freshwater environments like rivers, lakes, ponds, and streams, including the physical and chemical characteristics affecting life.Parasitology:
This branch examines parasitic organisms, their lifecycle, disease transmission, and interactions with hosts.Human Biology:
It covers all aspects of human life, including anatomy, physiology, health, inheritance, and evolution.Social Biology:
It studies the social activities of animals within populations, especially humans, and considers behavior that may be inherited from parents or developed due to environmental factors.Biotechnology:
It is a very modern and recent branch of biology. It deals with the study of (i) the use of data and techniques of engineering; and (ii) technology for studying and solving problems related to living organisms, especially in human beings.
Q.4: What are the different levels of biological organization?
Ans:
All living organisms have well-organized and highly complex bodies. This biological organization is not simple and is composed of different levels, starting from the basic level of sub-atomic and atomic particles up to the high level of individual whole organisms.
The levels of biological organization are as follows:
- Atomic and sub-atomic level
- Molecular level
- Cell and organelles level
- Tissue level
- Organ and organ system level
- Individual whole organism level
- Broader levels of organization:
- Species population
- Community
- Ecosystem
- Biosphere
Q.5: Define the following terms:
- Symbiosis
- Commensalism
- Mutualism
- Parasitism
Ans:
Defining the following:
Symbiosis:
When two living organisms live together in a way that is beneficial to both, it is called symbiosis.Commensalism:
The association between two organisms in which one benefits, while the other remains unaffected or gains no harm or benefit, is called commensalism. For example, saprophytic bacteria in the animal gut.Mutualism:
This is an association between two or more organisms in which both benefit from the relationship. When separated, both species can survive independently.Parasitism:
When two living organisms live together in such a way that one organism benefits and the other is harmed, it is called parasitism. For example, Plasmodium causes malaria in humans.
Q.6: What is the biological method? Explain hypothesis.
Biological Method:
The method used to solve problems in biology through observation, data collection, and experimentation is called the biological method.
Steps of the biological method are as follows:
Observation:
It is the identification of a biological problem. Through deep observation, the problem can be understood properly.Data Collection:
Deep observation helps to gather all facts and information about the work, which has been reported by others. This process is called data collection.Hypothesis:
Based on these facts and information, a tentative statement is prepared by the scientist, known as a hypothesis.Reasoning:
The hypothesis can guide further observations and experiments. Reasoning can be of two types:Inductive Reasoning:
Isolated facts are used to form a general idea to explain a phenomenon.
Example: In 1665, Robert Hooke observed a piece of cork under a microscope and identified small chambers, which he called cells. This work contributed to further cell research, leading to the cell theory by M.J. Schleiden and T. Schwann.Deductive Reasoning:
This involves general assumptions and experiments to reach a conclusion.
Experimentation:
In the biological method, further experiments are necessary to achieve accurate results.Conclusion:
On the basis of experiments, observations, and new data collection, conclusions are drawn.Theory:
A theory is presented to the world based on conclusions. If the hypothesis is true, the theory is accepted; otherwise, it is rejected.Law:
When a theory is accepted and proven true, it is considered a general principle, i.e., a law.
Q.7: Write a note on the importance of biology?
OR
Application of biology for the welfare of mankind?
Ans:
Application of Biology for the Welfare of Mankind:
Biology is a very important field of science with great significance for the welfare of mankind. Its applications include:
- Helping to improve the standard of life.
- Promoting better health.
- Assisting in the protection and conservation of the environment.
- Applying modern technology in agriculture to improve the quality and quantity of crops, solving food and other essential issues.
- Utilizing modern technology in medical sciences.
Some applications of biology in medical sciences are as follows:
Immunization:
Immunization, or resistance against diseases, is achieved through vaccination worldwide. This technique has helped control diseases like polio, smallpox, and hepatitis, significantly reducing infection and infant mortality rates. Edward Jenner first introduced vaccination in 1795 to protect against dangerous diseases like polio, hepatitis, and smallpox.Antibiotics:
Antibiotics are substances used to inhibit the growth of microorganisms. The first antibiotic, Penicillin, was isolated from the fungus Penicillium notatum. This work, done by Fleming, Flory, and Chain, earned them the Nobel Prize. Antibiotics are widely used to control diseases such as TB, cholera, leprosy, and anthrax.Chemotherapy:
Biology constantly aims to develop new medicines for disease treatment. Recently, harmful diseases like AIDS and cancer are treated with certain chemicals in a process called chemotherapy.Radiotherapy:
The use of radioactive rays (X-rays) is widely used in treating diseases. This technique is called radiotherapy, which is also useful for diagnosing diseases. Radiotherapy is primarily used to treat cancer, but it is expensive and painful.Food Shortage Due to Population Increase:
Due to the increase in population, there is always a shortage of food and other necessities. Modern technology in agriculture and related fields can help increase food production.
Q.8: What is Hydroponics?
Ans:
Hydroponics:
It is a soil-less or water culture technique in which terrestrial plants are grown in an aerated solution. This technique allows vegetables and other plants to grow, helping meet the food needs of a particular area. Tomato crops and other vegetables are cultivated in greenhouses using this technique, yielding satisfactory production.
Advantages of Hydroponics:
Using this technique, crops can be protected from soil diseases and weeds. In dry regions, some crops can be grown successfully. For example, tomatoes and other crops are cultivated in greenhouses for production.
Q.9: What is Cloning?
Ans:
Cloning:
Cloning is a modern technique in biological science that produces duplicate copies of genetic material. It is a method of asexual reproduction, with all cloned members being genetically identical. Examples include regeneration, asexual reproduction in animals and plants, human twins, and cancer tumors.
In 1996, scientists in Scotland successfully cloned a sheep named "Dolly." This technique is successfully applied in lower mammals.
Procedure of Cloning:
In cloning, the nucleus of an egg is removed, and a nucleus from a fully developed individual is introduced into the egg.
The modified egg is then implanted into a female's womb for complete development. The resulting individual is very similar to the one whose nucleus was used.
Importance of Cloning:
- By cloning, different kinds of human cells can be prepared, such as liver cells, skin cells, and blood cells. This may enable the development of human body organs, allowing defective organs to be replaced by cloned ones.
- This technique can improve quality in agriculture and medical sciences.
- Growth hormones, insulin, and other substances can be produced through cloning.
- Cloning can reduce the area needed for cultivation.
- It can also help in determining essential minerals and understanding plant structures.
Q.10: Write a note on Protection and Conservation of Environment?
Ans:
Human beings and other organisms live in a particular environment that provides nourishment and basic needs. This environment faces damage in various ways.
Pollution:
Pollution harms our environment and exists in multiple forms, such as air, water, and land pollution. Acid rain, greenhouse effects, and waste matter with toxic substances contribute to pollution, directly affecting the lives of organisms.To protect the environment, practical methods to reduce or minimize pollution are essential. A healthy environment is necessary for all living organisms.
Deforestation & Industrialization:
Activities like deforestation, industrialization, and other human interventions disturb the natural biological systems in the environment.Conserving forests helps reduce soil erosion and flooding. By protecting various plant and animal species, a stable and balanced ecosystem can be maintained.
