Week 2 Flashcards
favored trait =
trait that survives best
the similarity between Lamarck’s and Darwin’s theories
results in evolution through interactions with individuals and their environment
natural selection is not…
goal-oriented
why does NS lag one generation behind?
due to the previous environment
NS acts for the benefit of the…
individual
How does NS make new species (speciation)? - 4 steps
populations become isolated in separate environments, NS promotes different traits in different environments, isolated populations no longer mate successfully, and populations become permanently reproductively isolated
Reproductive Isolation
populations within species become isolated from each other
Allopatric Speciation
gene flow is disrupted when populations become physically separated and isolated from each other
Sympatric Speciation
a less common mode of speciation that occurs in populations that live in the same geographic area
What conditions are required for sympatric speciation?
polyploidy and habitat differentiation
Polyploidy
genome mutation is meiosis that prevents recombination and results in diploid gametes instead of haploid, which means the cell cannot reproduce with normal haploid gametes
habitat differentiation
existence of multiple types of habitats within a specific geographic area
Prezygotic Barriers of Hybridization
prevents organisms of different species from mating with each other
Postzygotic Barriers of Hybridization
hybrid offspring are inviable - hybrids don’t survive or are sterile
Traits can be similar between species because…
they inherit the trait from a common ancestor (homology) or they independently evolve similar features because of similar NS (convergent evolution)
Homology
the similarity in structure or function between different organisms based on shared ancestry, often modified for different reasons
Convergent Evolution
organisms that aren’t closely related evolve similar features or behaviors, often as solutions to the same problem(s)
