natural selection and evolution Flashcards
What are adaptations?
a modification of an organism or its parts that makes it more fit for existence
What are the conditions necessary for natural selection to occur?
a struggle for existence, variation and inheritance
What does the term “fitness” mean as it relates to natural selection?
reproductive success and reflects how well an organism is adapted to its environment
Are mutations always bad?
no
what is gene flow?
the transfer of genetic material from one population to another
what is the founder effect?
the reduced genetic diversity which results when a population is descended from a small number of colonizing ancestors.
What is the bottleneck effect?
when a population is greatly reduced in size, limiting the genetic diversity of the species
what is a homologous structure?
similar physical features in organisms that share a common ancestor, but the features serve completely different functions
what is an anologous structure?
features of different species that are similar in function but not necessarily in structure and which do not derive from a common ancestral feature and which evolved in response to a similar environmental challenge
what is a vestigial structure
Structures that have no apparent function and appear to be residual parts from a past ancestor
What do similar embryos tell us about two different species
evidence of common ancestry
What do similar DNA sequences and protein structures tell us about two different species?
strong evidence supporting evolution
Why are transitional fossils so important to evolutionary theory?
