Homework Chapter 17 & 18

What is the difference between microevolution and macroevolution? a. It is a somewhat arbitrary distinction based on the amount of evolution which has taken place over a time span. b. Microevolution is hypothetical because changes are too small to be observed, whereas macroevolution is detectable. c. Microevolution deals with microscopic organisms, whereas macroevolution deals with larger ones. d. Microevolution describes what happens in small populations, whereas macroevolution deals with large populations.

a. It is a somewhat arbitrary distinction based on the amount of evolution which has taken place over a time span.

On a remote Pacific island, exists a species of rabbits can which have very short ears. During a storm, a crate containing live long-eared rabbits of the same species is washed over the side of a ship and eventually washes onto the shore of the island. This event causes the rabbit population of island to be immediately be changed from all short-eared rabbits to one in which 80% of them have short ears and 20% have long ears. This would be an example of microevolution through ______. a. gene flow b. mutation c. natural selection d. genetic drift

a. gene flow

A group of organisms that can successfully interbreed... a. is referred to as a species b. shares the same genotype c. is very difficult to find in nature. d. shares the same phenotype

a. is referred to as a species

One of the reasons that natural selection works on populations rather than on individuals is that _____________. a. populations are too large for natural selection to have an effect b. A population has many generations over which the allele frequency can change, whereas an individual's alleles don't change c. Natural selection only brings about macroevolution (which only applies to populations), and not microevolution (which only applies to individuals) d. individuals can develop new alleles, but populations cannot e. populations have different genes than do individuals

b. A population has many generations over which the allele frequency can change, whereas an individual's alleles don't change

An allele is ________. a. a genotype b. a particular version of a gene c. the gene pool of a population d. a particular characteristic

b. a particular version of a gene

The term "Natural Selection" is not interchangeable with the term "evolution" because: a. Natural Selection is just a theory, whereas evolution has been proven. b. a population may evolve in ways other than through Natural Selection. c. Darwin coined the term evolution, but not Natural Selection. d. Natural Selection does not always lead to evolution.

b. a population may evolve in ways other than through Natural Selection.

In what type of cells must mutations occur before the mutations can be important in evolutionary change within a population? a. autosomes b. gametes c. blood cells d. somatic cells

b. gametes

One of the reasons that natural selection can bring about evolution is because of variation in the genetic material of a population. What is the ultimate source of the variation in genetic material? a. the number of offspring produced by an organism b. genetic mutations c. the life span of an organism d. the feeding habits of a species

b. genetic mutations

Evolution that results in the formation of new species or other large groupings of living things is defined as _____________. a. microevolution b. macroevolution c. genetic drift d. natural selection

b. macroevolution

The longer two populations are kept from interbreeding, the: a. more recessive alleles will be expressed. b. more they will differ from one another in gene pools. c. greater the mutation rate will be. d. greater the chance one will go extinct.

b. more they will differ from one another in gene pools.

Which of the following evolutionary forces consistently works to adapt organisms to their environment? a. sexual selection b. natural selection c. mutation d. genetic drift e. gene flow

b. natural selection

Unlike natural selection, genetic drift is based solely on _________. a. mutations b. random events c. migrations d. the phenotype of the individual

b. random events

Which of the following could be considered a definition of "evolution"? a. a change in environmental conditions b. a change in the genetic makeup of an individual c. a change in the gene pool (sum of the alleles) of a population d. a change in the physical characteristics of an individual

c. a change in the gene pool (sum of the alleles) of a population

A population is ___________. a. only groups of animals; plants do not qualify as populations. b. all of the organisms in an ecosystem c. members of the same species in a given area d. all of the organisms in a given area

c. members of the same species in a given area

Microevolution can be defined as a change in ______. a. environmental conditions on a very local level b. the types of alleles an individual carries as a result of mutations c. the phenotype of an individual resulting from the use or disuse of certain anatomical features d. the allele frequency within a population over a relatively short time

d. the allele frequency within a population over a relatively short time

Uranium-238 is a radioactive element that will decay into lead-206. It has a half-life of 4.5 billion years, which means that after 4.5 billion years exactly one-half of the total amount of uranium-238 that you started with will have decayed into lead-206. Suppose you were given a 100-gram solid block of uranium-238, and you buried it in the ground. Nine billion years from now, if someone dug it up and analyzed it, how much uranium-238 would be left? a. 75 grams b. 100 grams c. 0 grams d. 50 grams e. 25 grams

e. 25 grams