Exam 3: Natural Selection

Explain how natural selection has played an essential role in driving the modifications that have lead to the incredible biodiversity of life on Earth.

Why do exaptations provide challenges to evolutionary biologists' attempts to generate testable hypotheses about how natural selection produces adaptations?

Based on the figure above,use phylogenetic reasoning to explain whether feathers evolved for flight,and why.What other possible advantages could feathers provide? Is there a way to determine which was the original selective function? Explain your answer.

Gene sharing is

In principle,the variations in oldfield mouse coat color illustrated in the figure above could result from

According to the figure above,plants with genotype 1

The text presents the experiments of Richard Lenski and his colleagues,who set up long-range experiments on E.coli.In the experiment illustrated in the figure above,12 parallel E.coli lineages were created and maintained,cells from each line were periodically frozen,and the team followed the lineages for more than 50,000 generations.Why were these experiments groundbreaking? How have these experiments revolutionized the sorts of questions evolutionary biologists can ask?

An exaptation is a

A trait that serves one purpose today but evolved under different selective conditions is

According to the figure above,which of the following statements is true?

The term for a simultaneous action of natural selection on each side of the host-pathogen interaction is known as a(n)

Explain the figure above,including how the study graphed here illustrates the concept of "norm of reaction."

Geological evidence reveals that the barrier islands where the populations of oldfield mice shown in the figure above occur formed only 6000 years ago.Presumably,divergence in coat color occurred after the islands' formation (Hoekstra et al.2006).Explain how these dramatic variations in coat color between populations could have evolved over such a short period relative to the scale of evolutionary time.

Evolutionary change in one species that affects the selective conditions for a second species is known as

Considering the phylogenetic evidence that feathers evolved prior to flight,what might have been the original function of feathers?

Compare the placement of eyes in an ostrich to that in an owl.What are the trade-offs in physical constraint that each faces?

Natural selection is the consequence of

The formal definition of "fitness" in evolutionary biology

Imagine you are an evolutionary biologist studying reproductive trade-offs in populations of guppies that have been separated by the formation of barrier waterfalls.The upstream population faces lower predation than the downstream population,and the predators on the downstream side are larger and can eat any guppy offspring,no matter the size.Make a prediction about the reproductive strategies you might find and explain the trade-offs faced by the reproducing female guppies on each side of the barrier.

Describe some ways in which,at the molecular level,the process of evolution tinkers with existing structures to produce novel functions.