Collection of Biology Volume 1

Biology is the study of life. It is the study of living organisms and how they interact with the environment. Biology recognizes the cell as the basic unit of life, genes as the unit of heredity and evolution as an engine which boosts the formation of new species.
•Life Processes.
•How Do Organisms Reproduce.
•Heredity and Evolution.
•Control and Coordination.
•Our Environment.
•Management of Natural Resources.
There are six life processes that all living organisms perform. They are movement, respiration, growth, reproduction, excretion and nutrition. The chapter also teaches about nutrition which means the process of taking in food and using it for growth, metabolism and repair. Nutritional stages are ingestion, digestion, absorption, transport, assimilation, and excretion. Nutrition is further divided into Autotrophic Nutrition and Heterotrophic Nutrition. Autotrophic nutrition involves the intake of simple inorganic materials from the environment and using an external energy source like the Sun to synthesize complex high-energy organic material.
The responses of the nervous system can be classified as a reflex action, voluntary action or involuntary action. The nervous system uses electrical impulses to transmit messages. It gets information from our sense organs and acts through our muscles. Chemical coordination is seen in both plants and animals. Hormones produced in one part of an organism move to another part to achieve the desired effect. A feedback mechanism regulates the action of the hormones.
Unlike other life processes, reproduction is not essential to maintain the life of an individual organism. How do Organism Reproduce chapter involves the creation of a DNA copy and additional cellular apparatus by the cell involved in the process. Depending on their body design, various organisms use different modes of reproduction. In fission, many bacteria and protozoa simply divide into two or more daughter cells. Organisms such as hydra can regenerate if they are broken into pieces. They can also give out buds which mature into new individuals. Roots, stems and leaves of some plants develop into new plants through vegetative propagation.
We have discussed how some amount of variation is produced even during asexual reproduction. The Rules for the Inheritance of Traits in human beings relate to the fact that both the father and the mother contribute practically equal amounts of genetic material to the child. This means that each trait can be influenced by both paternal and maternal DNA. Sex can be determined by different factors in various species. Changes in the non-reproductive tissues caused by environmental factors are not inheritable. Speciation may take place when the variation is combined with geographical isolation. Evolutionary relationships are traced in the classification of organisms. Tracing common ancestors back in time leads us to the idea that at some point in time, non-living material must have given rise to life.