Biology Chapter 22

Which of these conditions are always true of populations evolving due to natural selection?

-The population must vary in heritable traits -One or more heritable traits must comparatively increase reproductive success

Given a population that contains genetic variation, what is the correct sequence of the following events under the influence of natural selection? 1. Well-adapted individuals leave more offspring than do poorly adapted individuals 2. A change occurs in the environment 3. Genetic frequencies within the population change 4. Poorly adapted individuals have decreased survivorship

2 - 4 - 1 - 3

Of the following anatomical structures, which is homologous to the bones in the wing of a bat?

Bones in the flipper of a whale

Many crustaceans (for example, lobsters, shrimp, and crayfish) use their tails to swim, but crabs have reduced tails that curl under their shells and are not used in swimming. This is an example of _____

A vestigial trait

Darwin used the phrase "descent with modification" to explain

Evolution of the unity and diversity of life

Birds, bats, and insects all fly. Flight in these animals can be considered ____

Analogous

The cow Bos primigenius (which is bred for meat and milk) has a smaller brain and larger eyes than closely related wild species of ungulates. These traits most likely arose by ________

Artificial selection, because changes in these traits co-occurred with human selection for high milk output and high muscle content

Darwin and Wallace's theory of evolution by natural selection was revolutionary because it

Dismissed the idea that species are constant and emphasized the importance of variation and change in population

Which of the following statements describe the effect of evolution on a population?

Increasingly better match between a population and its environment

The Linnaeus classification system grouped organisms by ______

Increasingly more complex categories

Which of the following statements describe evolution?

Individuals evolve in response to their environment

Which statement illustrates the connection between natural selection and overreproduction of a population?

Individuals with inherited traits that promote survival tend to have more surviving offspring

What are adaptations?

Inherited characteristics of an organism that enhances their survival

It has been observed that organisms on islands are different from, but closely related to, similar forms found on the nearest continent. This is taken as evidence that ____

Island forms are descended from mainland forms

The upper forelimbs of humans and bats have fairly similar skeletal structures, where the corresponding bones in whales have very different shapes and proportions. However, genetic data suggests that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

Natural selection in an aquatic environment resulted in significant changes in whale forelimb anatomy

Which of the following evidence most strongly supports the common origin of all life on Earth? All organisms _____

Use essentially the same genetic code

The question refers to the evolutionary tree, in which the horizontal axis represents time (present time is on the far right) and the vertical axis represents morphological change. Which species is most closely related to species W? Select all that apply.

V

Animals with a common ancestor often share many homologous traits. Some of these traits may no longer be used; what are these traits called?

Vestigial

Currently, two of the living elephant species (X and Y) are placed in the genus Loxodonta and a third surviving species (Z) is placed in the genus Elephas. Assuming this classification reflects evolutionary relatedness, which of the following is the most accurate phylogenetic tree?

Z on a branch alone. X and Y on a split branch.