Module 11 Flashcards
What is Evolution?
A change in allele frequency (or genetic makeup) of a population over time. (Populations are the units of evolution)
What is natural selection?
Process through which living organisms adapt and change.
What is the recipe for natural selection?
- Variation
- Heritability (the variation is heritable)
- Reproductive advantage (the variation influences the reproductive success of individuals)
What is sexual selection?
Selection of a trait that increases an individual’s chance of mating even if that trait decreases the individual’s chance of survival.
What is evolutionary fitness?
How well a species is able to survive and reproduce in it’s environment. Survival of the “fit enough”
What are sources for genetic variation?
- Independent assortment during meiosis.
- Crossing over.
- Random fertilization.
(Random mutation is the ultimate source of genetic variation)
Mutations are ______; Natural selection is ___.
Random; not
What is divergent evolution? (Pattern of evolution)
Evolution in different directions from a common point; homologous structures indicate relatedness. Ex. Vertebrate forelimbs, reproductive structures in flowers.
What is convergent evolution? (Pattern of evolution)
Similar structures arise due to similar selective pressures; analogous structures do NOT indicate the trait originated in common ancestor. Ex. Shark and dolphin body forms / bat and bird wings.
What are the evolutionary forces?
- Mutation
- Natural selection
- Genetic drift
- bottleneck effect
-founder effect - Gene flow
What is the biological species concept?
Defines a species as individuals capable of mating and producing fertile offspring.
What is genetic divergence?
The accumulation of genetic differences between two populations; requires reproductive isolation—could be prezygotic or postzygotic.
What is speciation?
Formation of new species.
What is allopatric speciation?
Occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.
What is sympatric speciation?
Splitting of species without geographical isolation.
