Chapter 16 and 17 Evolution ANSWERS

The hypothesis that all species are descended from common ancestors was proposed by

Charles Darwin.

In a fox population, the allele frequency of a gene for red fur changes from 20 percent to 30 percent. What can you say about that population of foxes?

The population is evolving.

Although they often live in the same habitat, the American toad breeds earlier in the spring than the Fowler's toad does. What can be inferred from this information?

The two species do not interbreed because of temporal isolation.

The frequency of phenotypes for a typical polygenic trait is most often illustrated as

a bell-shaped curve.

A large number of manatees is killed off due to a major hurricane event in the state of Florida, what type of effect may occur within this population relating to its gene pool

a bottleneck effect

A HOX gene is

a gene responsible for embryonic development of arms , legs and wings.

In organisms that reproduce sexually, most variation that can be inherited is due to

gene recombination during sexual reproduction

Which of the following events do biologists consider a random change?

genetic drift

The situation in which allele frequencies in the gene pool of a population remain constant is called

genetic equilibrium

The separation of populations by barriers such as rivers, mountains, or bodies of water is called

geographic isolation.

Jean Baptiste Lamarck proposed that organisms

have an innate tendency toward complexity and perfection.

Anatomical structures that have similar bone structure but do not have similar functions are called

homologous structures.

Which of the following ideas was NOT part of Darwin's contribution to science?

inheritance of acquired characteristics

Any change in the genetic material of a cell is called a

mutation.

What principle does the Grants' investigation of finch adaptation in the Galápagos Islands best support?

natural selection

Darwin first began to formulate his concept of evolution by natural selection after

observing patterns among the geographical location of certain species.

Natural selection acts directly on ___________, not ____________ .

phenotypes, genotypes

According to Darwin's theory of natural selection, individuals who survive are the ones best adapted for their environment. Their survival is due to the

possession of inherited adaptations that maximize fitness.

The geographic isolation of two populations of a species tends to increase differences between their gene pools because it

prevents interbreeding between the populations.

Species Y and Z have very similar proteins, genes and genetic sequences. What is most likely true about these two species? Species Y

shares a relatively recent common ancestor with Species Z.

Figure 17-2 shows highest fitness toward the center of the curve. When individuals with an average form of a trait have the highest fitness, the result is

stabilizing selection.

James Hutton's and Charles Lyell's work was important to Darwin because these scientists

suggested that Earth was old enough for evolution to have occurred.

The person/scientist(s) who had almost the same exact idea as Darwin did regarding natural selection and evolution and who ultimately forced Darwin to publish his results and write the Origin of Species.

Alfred Russell Wallace

Evidence that evolution does actually occur in nature is

All of the above

Which is a major concept included in Lamarck's evolutionary hypothesis?

Body structures can change according to the actions of the organism.

Each tick of a "molecular clock" is an occurrence of

DNA mutation

Anatomical structures that have similar functions but do not have similar structures are called

analagous structures

The definition of a species is

animals that can interbreed and produce fertile offspring.

When a dairy farmer chooses to breed the cows that give the most milk in the herd, the farmers are following the principle of

artificial selection.

Darwin realized that the economist Malthus's theory of population control

could be generalized to any population of organisms.

Genetic recombination includes the independent movement of chromosomes during meiosis as well as

crossing-over.

One end of Figure 17-1 shows an increase in average beak size for a population of birds. When individuals at only one end of a bell curve of phenotype frequencies have high fitness, the result is

directional selection.

Figure 17-3 shows smaller and larger beaks in a population of finches. One group of birds has a short, parrotlike beak and another group has a long, narrow beak. What process has probably occurred?

disruptive selection

Lateral gene transfer can be described as

exchange of genetic material between two individuals that are not offspring of each other

Charles Darwin called the ability of an organism to survive and reproduce in its specific environment

fitness.

A group of related genes that resulted from the duplication and modification of a single gene is called a

gene family

The genes carried by all members of a particular population make up the population's

gene pool.

The type of genetic drift that follows the colonization of a new habitat by a small group of individuals is called

the founder effect.

Molecular evidence in support of natural selection includes

the nearly universal genetic code (all DNA is made up of A, G, C and T's).

Allele frequency is

the number of times an allele appears within the population's gene pool

A single gene trait that has two alleles and that shows a simple dominant-recessive pattern will result in

two phenotypes.

In humans, the pelvis and femur, or thigh bone, are involved in walking. In whales, the pelvis and femur shown in Figure 16-1 are

vestigial structures.

Biogeography is the study of

where species and ancestors live

If a mutation introduces a new skin color in a lizard population, which factor might determine whether the frequency of the new allele will increase?

whether the mutation makes some lizards more fit for their environment than other lizards

The economist Thomas Malthus suggested that

without certain checks on population size, there would soon be insufficient food for the growing human population.