section 1

Question 1

What is evolution?

Answer 1

descent with modification; change in allele frequencies in a population over time.

Question 2

a population consists of

Answer 2

interbreeding members of the same species

Question 3

In ancient Greece, Aristotle (384–322 bce) recognized that

Answer 3

all organisms are related in a hierarchy of simple to complex forms, but he believed that all members of a species were created identical to one another in form and capacity. This idea influenced scientific thinking for nearly 2000 years

Question 4

In 1749, French naturalist Georges-Louis Buffon (1707–1788) became one of the first to openly suggest that

Answer 4

closely related species arose from a common ancestor and were changing

Question 5

In 1785, physician James Hutton (1726–1797) proposed the theory of

Answer 5

uniformitarianism, which suggested that the processes of erosion and sedimentation that act in modern times have also occurred in the past, producing profound changes in Earth over time

Question 6

Georges Cuvier (1769–1832) was convinced of the theory of

Answer 6

catastrophism,the theory that a series of brief, violent, global upheavals such as enormous floods, volcanic eruptions, and earthquakes were responsible for most geological formations.

Question 7

Curvier was also the first to recognize the

Answer 7

principle of superposition—the idea that lower layers of rock (and the fossils they contain) are older than those above them

Question 8

French taxonomist Jean Baptiste de Lamarck (1744–1829) proposed

Answer 8

the first scientifically testable evolutionary theory. He reasoned that

• organisms that used one part of their body repeatedly would increase their abilities, very much like weight lifters developing strong arms.
• disuse would weaken an organ until it disappeared.
• surmised (incorrectly) that these changes would pass to future generations.

Question 9

Geologist Charles Lyell

Answer 9

• suggested that natural processes are slow and steady, and that Earth is much older than 6000 years
• concluded that gradual changes in some organisms could be represented in successive fossil layers.
• was so persuasive that many scientists began to reject catastrophism in favor of the idea of gradual geologic change.

Question 10

John Gould studied

Answer 10

the finches Darwin brought back from the Galapagos. He studied their beak structures and described 14 diff types of finches.

Question 11

Darwin thought that the different varieties of finches on the Galápagos had:

Answer 11

• probably descended from a single ancestral type of finch that had flown to the islands
• He coined the phrase “descent with modification” to describe gradual changes from an ancestral type.

Question 12

Economist and theologian Thomas Malthus’s Essay on the Principle of Population stated

Answer 12

that food availability, disease, and war limit the size of a human population. Individuals that could not obtain essential resources would die.

Question 13

natural selection occurs when

Answer 13

environmental factors cause the differential reproductive success of individuals with particular genotypes.

Question 14

Artificial selection occurs

Answer 14

• when a human chooses one or a few desired traits and then allows only the individuals that best express those qualities to reproduce
• responsible not only for agriculturally important varieties of animals and plants but also for the many breeds of domesticated cats and dogs

Question 15

In the 1930s, scientists finally recognized the connection between natural selection and genetics. They unified these ideas into the

Answer 15

modern evolutionary synthesis, the idea that genetic mutations create the variation upon which natural selection acts

Question 16

Microevolution

Answer 16

the relatively short-term genetic changes within a population or species, occurs on a much smaller scale

Question 17

Because an individual’s alleles do not change,

Answer 17

evolution can occur in populations but not in individuals.

Question 18

Adaptations

Answer 18

features that provide a selective advantage because they improve an organism’s ability to survive and reproduce.

Question 19

in an evolutionary sense, fitness refers to

Answer 19

an organism’s genetic contribution to the next generation

Question 20

Biologists can detect evolution by examining

Answer 20

a population’s gene pool—its entire collection of genes and their alleles.

Question 21

Each genotype’s frequency is

Answer 21

the number of individuals with that genotype, divided by the total size of the population

Question 22

Hardy—Weinberg equilibrium

Answer 22

is the is the highly unlikely situation in which allele frequencies and genotype frequencies do not change from one generation to the next.

Question 23

Hardy—Weinberg equilibrium occurs only in populations that meet the following assumptions:

Answer 23

(1) mutations do not occur, so no new alleles arise
(2) individuals mate at random;
(3) individuals do not migrate into or out of the population;
(4) the population is infinitely large, or at least large enough to eliminate random changes in allele frequencies (genetic drift)
(5) natural selection does not occur.