The Origin of Species

1) What is microevolution?

Microevolution is the change in the genetic makeup of a population from generation to generation. (adaptations that are confined to a single gene pool).

2) What is macroevolution?

Macroevolution is an evolutionary change above the species level (ex. feathers).

3) What are some factors (from this chapter) that can result with two distinct species formed?

isolation, selection, mutation, genetic drift

Facts:

- The biological species concept emphasizes reproductive isplation

- The two main types of speciation are allopatric speciation and sympatric speciation

- Polyploid speciation occurs in animals but is not common

- Adaptive radiation occurs when many new species arise from a single common ancestor

- Speciation (process by which new species arise) can occur rapidly or slowly, and it can result from changes in few or many genes

diversity!

Summary:

Speciation, the origin of new species, is at the focal point of evolutionary theory because the appearance of new species is the source of biological diversity. Speciation addresses the question of how new species originate and develop through the subdivision and subsequent divergence of gene pools. Species are based on interfertility, not physical similarity. Because the distinction between biological species depends on reproductive incompatibility, the concept hinges on reproductive isolation, the existence of biological barriers that prevent members of two species from producing viable, fertile hybrids.

Reduced hybrid viability. Genetic incompatibility between the two species may abort the development of the hybrid at some embryonic stage or produce frail offspring.Evolutionary biologists have proposed several alternative concepts of species. Two general modes of speciation are distinguished by the way gene flow among populations is initially interrupted. How significant a barrier must be to limit gene exchange depends on the ability of organisms to move about. Individuals of two closely related sympatric cichlid species will not mate under normal light because females have specific color preferences and males differ in color.

Extra:

speciation