GRE Subject Test: Biology : Understanding Divergent and Convergent Evolution
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Example Questions
Example Question #1 : Speciation
Which of the following is an example of convergent evolution?
A species regains a trait that an ancestor had previously lost
Two different species independently gain the ability to fly
Two populations living in the same geographic region acquire enough differences to diverge into two separate species
Two species merge together to form a single species
Two different species independently gain the ability to fly
Convergent evolution is the phenomenon by which two separate species evolve a shared trait. A classic example of this is that both birds and bats have evolved wings, but do not share a common ancestor prior to the development of this trait. Birds and bats developed their wings separately through completely unique mechanisms.
A population diverging into two separate species while residing in the same area describes the phenomenon of sympatric speciation. A species regaining a trait is an example of evolutionary reversal.
Example Question #1 : Speciation
An example of __________ is the speciation of Darwin's finches through the accumulation of many small, distinct traits.
artificial selection
parsimony
divergent evolution
convergent evolution
divergent evolution
Convergent evolution is the phenomenon by which two species independently evolve a similar trait. An excellent example is the evolution of flight/wings in birds and bats, which do not share a common ancestor. Parsimony is a principle that guides scientific explanation toward simple terms, rather than eleborate principles. By parsimonious thinking, the simplest explanation is also the most likely to be true. Artificial selection is a form of evolution in which organisms are selected and bred for beneficial traits that would not necessarily be selected for in nature. Dog breeding and the production of numerous types of produce and grains are subject to artificial selection by humans (this is different from genetic modification).
Divergent evolution describes the accumulation of distinct traits that can lead to speciation events. A large population consists of a single ancestor species. Over time, different groups of the population come to inhabit different niches and develop traits for specialized inhabitance of that niche. As these changes accumulate, the population slowly develops distinct groups. When these groups can no longer reproduce due to some sexual barrier, a speciation event has occurred. This process aligns with the theory of evolution for Darwin's finches.
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