Science Quiz

Concept 2 Notes: Patterns of Evolution

Speciation

• Speciation - forming of a new species by evolution from pre-existing species.

- Gene pools gradually become different & are no longer able to reproduce.

• At this point the 2 groups are different species.

Extinction- Elimination of species

Gradual extinction- Occurs at a slow rate

Mass extinction - Occurs when a catastrophic event changes the environment suddenly

Gradualism- Slow changes over a long period of time

Punctuated equilibrium burts  of change followed by  periods of stability 

Adaptive Radiation (divergent evolution)

A number of different species arise from on common ancesto

• New environments caused them to evolve to be different

Convergent evolution

• When unrelated species evolve similar characteristics because they live in similar environments

• Geoginisms change in response to each other forming a specialized relationship

Sexual v. Asexual Reproduction

• • Sexual Reproduction: takes two organisms to make offspring; process of meiosis to create gametes

• - Genetic changes • transcription/translation of different proteins change in phenotype of an individual organism

• - Makes organisms better suited for changing environments

• • Asexual Reproduction: process of binary fission or mitosis where only one parent produces genetically identical offspring

• - Genetic variation can only occur through mutations of

• - Better suited for stable environments