Define organic evolution and explain divergent and convergent evolution with examples.

a) Organic evolution is the process by which living organisms change over successive generations, leading to the development of new species from pre-existing ones. This change occurs through mechanisms like natural selection, genetic drift, and mutation.

b)

• Divergent evolution occurs when two or more species share a common ancestor but evolve different traits over time due to different environmental pressures or adaptations to different niches. Example: The forelimbs of mammals (e.g., human arm, bat wing, whale flipper) have a similar basic bone structure inherited from a common ancestor but have evolved to perform different functions.

• Convergent evolution occurs when species with different ancestral origins evolve similar traits independently due to adapting to similar environments or ecological niches. Example: The wings of birds and insects both allow for flight but evolved from different structures in unrelated ancestors.