Chapter 13 Core Content

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.

genetic drift

The evolution of populations due to chance is

genetic drift.

In a population with brown and green alleles for color, genetic drift

has more effect on the evolution of a small population.

Which of these gametes contain one or more recombinant chromosomes?

B, C, F, and G

What did Wallace conclude from observing that the bones in manatee flippers look similar to the bones in a human arm and hand?

Manatees' arm and finger bones are evidence that manatees share a common ancestor with land mammals

When Charles Darwin set sail on the HMS Beagle, what did he and most of his contemporary scientists think about the origin of species?

Most scientists, including Darwin, thought each species was specially created by God in its present form and did not change over time.

Which of the following is a true statement?

Species with nucleotide sequences that match closely share a common ancestor.

According to the Hardy-Weinberg formula, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.

sexual reproduction

The population of American bison used to number in the millions of animals. Hunting and other problems greatly decreased the number of bison to about 1,000 animals. Today, the numbers are recovering to estimates of more than 200,000 animals. This crash in the population of bison and recent recovery is an example of _

the bottleneck effect

Which of the following is the most recent example of an evolutionary change in populations?

the development of pesticide-resistant insects

Which of the following is an example of natural selection that has been seen in our lifetime?

the evolution of antibiotic-resistant bacteria

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles,

the frequency of the green allele will increase.

After his journey on the HMS Beagle, Darwin made this now-famous sketch in his notebook. Which ideas does it represent?

All species are connected to one another in a "family tree." All species are linked to one another by common ancestry. Species descend from other species just as naturally as children come from parents.

Suppose that every few years, all people over 6 feet tall do not have any children. How will this affect the human population?

Alleles that promote "tallness" will decrease in frequency

Darwin and Wallace independently arrived at the same conclusion that species change over time. Which observations supported their conclusions?

Bird families clustered geographically: cockatoos in the Malay Archipelago and Australia, macaws and hummingbirds in the Americas. Tortoises from different Galapagos islands have distinct shells. The fossilized remains of giant sloths were similar to the smaller, living sloths Darwin encountered. Birdwing butterflies were found throughout the Malay archipelago, but species differed slightly from island to island. The bony shells of armadillos resembled fossilized shells from the extinct Glyptodon. Mockingbirds from different Galapagos islands had subtle, consistent differences

As Wallace traveled the Malay Archipelago, he noticed that western islands had placental mammals, like monkeys. Eastern islands had marsupial mammals, like kangaroos. How did Wallace explain this distribution?

The western islands were once connected to Asia and the eastern islands had been connected to Australia. The islands had never been connected to each other.

The ease with which humans travel across the globe is likely to increase

gene flow

Can you identify the mechanisms of evolution illustrated by each of these examples?

gene flow bottleneck effect bottleneck effect gene flow sexual selection founder effect

All the genes in a population are that population's

gene pool

The relationship of the genome to an organism is the same as that of the _____ to a population.

gene pool

In recessive lethal diseases such as Tay-Sachs disease, carriers have one copy of the normal allele and one copy of the allele for the disease. Carriers are represented in the Hardy-Weinberg formula by _

2pq

In evolutionary terms, an organism's Darwinian fitness is measured by its ____

contribution to the gene pool of the next generation

In human gamete production there is an average of _____ crossover events per chromosome pair.

2-3

Which of these individuals is a homozygous genotype?

AA

Darwin and Wallace made independent observations in different parts of the world. Which statements are true?

Both collected huge numbers of specimens and realized that individuals vary within species. Both witnessed nature up close and realized it was a battlefield with massive casualties. Both observed slightly different species on nearby islands and concluded that species could change over time.

Which of the following statements about early ideas of evolution is true?

Fossil discoveries in the early 1800s convinced many naturalists that species are not fixed and can change over time.

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct?

Gene flow causes the frequency of the brown allele to increase.

Can you place each example into the appropriate category of scientific evidence of evolution?

OBSERVATION FOR NATURAL SELECTION IN ACTION 1. development of pesticide resistance in insects 2. changes in average beak size in finches following wet or dry years FOSSIL RECORD 1. discovery of bones from many different dinosaur species 2. transitional forms that link whales with land-dwelling ancestors that are now extinct BIOGEOGRAPHY 1. unique collection of marsupial mammals in australia 2. resemblance of island species to nearby mainland species ANATOMICAL AND MOLECULAR HOMOLOGIES 1. similar forelimb anatomy in different species of mammals 2. same genetic language of dna and similar genes in yeasts, fruit flies, and humans

According to current evolutionary theory, which of the following is true?

Populations are the units of evolutions.

To help prevent the proliferation of antibiotic-resistant bacteria, you should _

Take the full course of any antibiotics your doctor has prescribed.

Which observations led Darwin to establish a relationship between extinct and living animals?

The fossilized remains of giant sloths were found in places where smaller sloths now live. The bony shells of armadillos resembled the shells of ancient Glyptodon fossils.

Imagine that a new population of humans is established on a new planet from ten randomly selected people in your biology class. Over thousands of years, the descendants of those ten people reproduce and prosper, but do not reflect well the diversity of humans on Earth. This change in the diversity of people on the new planet is an example of _____.

The founder effect

Can you complete this concept map that reviews some key ideas about evolution?

a. genetic variation b. evolution c. hardy-weinberg equilibrium d. sexual reproduction e. allele frequencies f. genetic drift g. adaptations

Can you identify the type of evidence for evolution illustrated by each example?

bioinformatics fossil record comparative anatomy biogeography fossil record bioinformatics biogeography

Homologous pairs of chromosomes are lined up independently of other such pairs during

metaphase I

A process in which organisms with certain inherited characteristics are more likely to survive and reproduce than individuals with other characteristics is called _

natural selection

Crossing over, resulting in an increase in genetic variation, occurs between

nonsister chromatids of homologous chromosomes

Genetic drift is a process based on

the role of chance

A mutation occurs when __

there is a change in the DNA sequence of a gene

Remember that color is an inherited trait in beetles. Which of the following is an example of natural selection?

Green beetles leave more offspring than brown beetles because they are better at finding food.