25 Important Topics in Biology
Following are a list of biology topics that have been carefully selected according to their scope and importance. These topics are elementary and form the basis of much more advanced concepts in higher classes. Moreover, questions frequently arise from these topics in various competitive exams. Hence, students will find this list most beneficial for their exam preparations.
1. Photosynthesis
Photosynthesis an important process that is observed in plants and certain microscopic organisms. Furthermore, all life on earth is directly or indirectly dependent on this process. It is even speculated that the evolution of life on earth was significantly influenced by photosynthesis.
2. Carbon Cycle
The carbon cycle is a biogeochemical process that also has a significant impact on life. The cycle essentially explains how carbon is incorporated and exchanged among the various entities (such as living organisms, atmosphere, lithosphere, hydrosphere etc).
3. Nitrogen Cycle
Nitrogen is an important element required for life. However, neither plants nor animals can extract nitrogen directly from the atmosphere, instead, they rely on a series of biological and/or physical processes to incorporate into their systems. These set of processes contribute to the nitrogen cycle.
4. Difference Between Mitosis And Meiosis
Mitosis and meiosis are two types of cell divisions that are observed in living organisms. One of the major differences between the two is that mitosis occurs during growth and maintenance while meiosis occurs only during sexual reproduction.
5. Flora And Fauna
Flora refers to all plant life while fauna refers to all animal life. There are over 8.7 million species of living organisms identified to date and more being discovered every day. Life is so abundant that every nook and corner of the planet is teeming with life.
6. Human Digestive System
Digestion is an important life process and is observed in a multitude of life forms. Some have a rather simple system while others are much more complicated. Unsurprisingly, humans have a digestive system too, and it is much more advanced with a host of organs and glands that perform very specific functions and roles.
7. Human Heart
The heart is an important organ usually found in most higher animals. Even invertebrates have a heart that pumps blood into their cavities. However, unlike the invertebrates, the human heart is quite advanced with respect to its structure, functions and capabilities.
8. Sense Organs
To interpret the world around us, we have various senses and sense organs. These sense organs provide information which helps to make decisions and perceive the environment and associated stimuli.
9. Cells
The cell is the most basic, structural and functional unit of life. A cell can be classified based on various criteria (such as plant and animal cell, prokaryotic and eukaryotic cell, types of cells present in human tissues or plant tissues etc.
10. Human Brain
The brain is one of the most important organs which control nearly every aspect of our body. It is also one of the most complex organs in the entire body, with billions of neurons that relay information between the brain and the body.
11. Blood
Also called the fluid connective tissue, blood (and lymph) carries oxygen, essential minerals and nutrients to the cells. It also collects the metabolic waste products to be eliminated from the body. Humans are not the only organisms with blood, earthworms, spiders and even leeches have blood.
12. Soil Profile
The dirt beneath your feet is made up of several distinct layers, each with its own physical and chemical properties. Soil also varies from place to place due to their parent material (the original layer of rock where the formation of soil takes places.)
13. Transpiration
Transpiration is the process where water vapour is let out through the stomata on the leaves. It is a very crucial process that performs two major roles – pumping minerals and water to the leaves for photosynthesis and removing excess heat from the plants.
14. Gymnosperms
Gymnosperms are a group of seed-producing plants that have been around far longer than the angiosperms. The plant’s Greek-origin name translates to “naked seeds” as they the seeds are not enclosed in any way (unlike the angiosperms).
15. Saprophytes
Saprophytes are organisms that consume dead or decaying organic matter. Certain species of plants, bacteria and fungi follow this form of nutrition. However, fungi, in particular, are well-known saprophytes as they are the principal decomposers in an ecosystem.
16. Biofertilizers
Biofertilizer is a fertilizer that contains living or latent microbes. These forms of fertilizers help to promote plant growth by increasing the number of essential nutrients available to the plants. Traditionally used biofertilizers include Rhizobium, blue-green algae and Azospirillum.
17. Rhizobium
Rhizobium is an important soil bacteria that helps to convert the atmospheric nitrogen into fixed nitrogen, which is then usable by plants. It does this once it finds a base inside root nodules of plants such as legumes.
18. Ecology
Ecology is the branch of biology that deals with the relationships that exist between organisms and their surroundings.
19. Adaptation And Habitats
Life on earth resides in very diverse environments with many factors and variables (such as temperature, humidity, altitude etc). To ensure their best chances of survival, life develops various adaptations to cope up with the environment and with other life forms. One of the best examples of adaptations is camouflage, where predators and prey blend into their environment for predation or to avoid predation.
20. Evolution
Throughout the earth’s 4.54 billion years of history, countless organisms have come and gone. The very first undisputed signs of life appeared roughly 3.5 billion years ago, though there is divisive evidence that it emerged as early as 4.2 billion years. But the question of “How life came to be” still remains unanswered.
21. Plant Cell
Plant cells are vastly different from animal cells, though both are eukaryotic in nature. Moreover, plant cells do not have certain organelles like lysosomes or centrioles. However, they possess various other cell organelles that facilitate the process of photosynthesis such as chloroplasts.
22. Animal Cell
Animal cells are quite similar to plant cells. However, one of the major differentiating factors is the absence of a cell wall. Other organelles like chloroplasts are absent as well.
23. Difference between Prokaryotic and Eukaryotic Cells
One of the ways cells are classified is based on the presence or absence of a nucleus and nuclear membrane. Prokaryotic cells lack the aforementioned while eukaryotic cells do.
24. Heredity
Also known as biological inheritance, it is the set of processes where traits from parents are passed on to their offsprings either through sexual or asexual reproduction.
25. Biomolecules
A biomolecule is a term used to describe the molecules that are found in organisms and it takes part in important biological processes and cellular activities. Examples include proteins, carbohydrates, nucleic acids etc.