7.11: Micro And Macro Evolution, Extinction Flashcards
What is the bridge between the concepts of micro and macroevolution?
Speciation
What is microevolution?
- Change in allele frequencies within a single species or population (natural and sexual selection, genetic drift, gene flow)
What is macroevolution?
Large evolutionary patterns (adaptive radiation, mass extinction)
Macroevolution: what is stasis?
No change over long periods of time
Fitness is good
___ and ___ can occur at different speeds
Evolution and speciation
What are the two paces of speciation?
- Punctuated equilibrium
2. Gradualism
What is punctuated equilibrium?
When evolution occurs rapidly after a long period of stasis
What is gradualism?
When evolution occurs slowly over hundreds, thousands, or millions of years
What is divergent evolution?
- Groups with the same common ancestor evolve and accumulate differences, resulting in the formation of a new species
Adaptive radiation is a type of divergent evolution. What is adaptive radiation?
- if a new habitat or niche becomes available, species can diversify rapidly
Ex. Darwin’s finches, where one species comes, finds a new habitat, it speciated
Recap: what is convergent evolution? What does it include?
- two different species develop similar traits, despite having different ancestors
- Analogous traits
What is extinction?
The termination of a species
How many mass extinctions have occurs throughout earths history?
5
What affects extinction? (2)
- human activity can affect extinction rates
- ecological stress can quicken extinction rates
What happens if a species does go extinct?
- it opens up a niche that can be exploited by a different species
(One organism dying off leaves another to be successful)
