AP Inter 2nd Year Zoology Notes Chapter 7 Organic Evolution

Students can go through AP Inter 2nd Year Zoology Notes 7th Lesson Organic Evolution will help students in revising the entire concepts quickly.

AP Inter 2nd Year Zoology Notes 7th Lesson Organic Evolution

→ Evolution is the branch of biology that deals with the origin of life and the diversity of organisms on the earth through ages.

→ Theory of special creation states that organisms on the were created by a divine power.

→ Theory of spontaneous generation theory says that life originated from non-living (or) decaying and rotting substances like manure, dew etc.,

→ Theory of biogenesis thoery states that living organisms originate from pre-existing
organisms.

→ Theory of origin of life states that primitive organisms evolved from the inorganic substances as a result of physical forces such as lighting, ultraviolet radiation, volcanic activities etc.,

→ Study of prehistoric life through fossils called palaeontology.

AP Inter 2nd Year Zoology Notes Chapter 7 Organic Evolution

→ Lamarckism – proposed by Jean Baptiste de Lamarck. It deals with the influence of environment-on organisms, use (or) disuse of organs and the inheritence of acquired characters.

→ Darwinism – proposed by Charles Robert Darwin.

→ Darwin’s theory of natured solution explain how evolution might have occured in nature.

→ Mutation thoery was proposed by Hugo de vires.

→ Mutations are sudden, random inheritable changes that occur in organisms.

→ Hardy – Weinberg equilibrium – States that the allelic frequencies in a population will remain constant from generation to generation under certain conditions.

→ The process by which variations appear and new species are formed is called the Mechanism of evolution.

→ The forces that bring changes in the gene pool of populations are called evolutionary forces.

AP Inter 2nd Year Zoology Notes Chapter 7 Organic Evolution

→ The movement of alleles from one population to another is called gene flow.

→ The existance of deleterious genes within the populations is called genetic load.

→ The change in the frequency of agene that occurs merely by chance and not by selection, in small populations, is called genetic drift.

→ Speciation is a process by which one species, evolves into one (or) more different species.