Chapter 13 Homework
Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions?
Stabilizing selection
This unequal reproduction in a population leads to the gradual accumulation of ___________ to the environment.
adaptations
______________ favors phenotypes at one end of a range and is common in periods of environmental change.
directional selection
____________ favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied.
disruptive selection
The ___________ of life arises from the adaptation of species to different habitats over long spans of time.
diversity
A drought causes a habitat to turn dry and brown
environmental change
new individuals move into a population.
gene flow
Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.
genetic drift
by chance, some of the wildflowers in this population reproduce, while others do not
genetic drift
The evolution of populations due to chance is
genetic drift.
When Darwin wrote On the Origin of Species, he knew very little about the subject of _____, an essential component of evolutionary theory today.
genetics
Two key observations underlying natural selection are that members of a population vary in their _____________ and that all species can produce more offspring than the environment can support.
inherited traits
____________ is a type of sexual selection in which individuals of one sex (usually males) compete directly for mates. This may involve ritualized displays or physical combat.
intrasexual selection
Crossing over, resulting in an increase in genetic variation, occurs between _____.
nonsister chromatids of homologous chromosomes
Darwin inferred that those organisms with traits best suited to the environment tend to leave more __________ than other members of a population.
offspring
In the past, herbicides were very effective as a pigweed killer, but today _____.
pigweed is taking over fields of cotton and soybeans
Green beetles are more visible to birds than brown beetles, so birds eat more green beetles.
selective pressure
some insects have a gene that makes them resistant to the pesticide. These insects survive. Insects without the gene die.
selective pressure
In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in _______________, differences between the sexes in size, appearance, and behavior.
sexual dimorphism
Which of the following sets of animals are likely to be found on the Galapagos Islands?
tortoises, finches, blue-footed boobies
All of life is related through common ancestry, accounting for the _______ of life.
unity
Scientists studying evolution on the Solomon Islands described which animal as the 'poster child' for the biological species concept?
white-eye bird
In human gamete production there is an average of _____ crossover events per chromosome pair.
2-3
Where are the Galapagos Islands located?
600 miles west of Ecuador, near the equator
Which of these individuals is a homozygous genotype?
AA
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.
In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat,which type of selection would act on shell color in these snails?
Disruptive selection
Natural selection is best described as _____.
a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations
same genetic language of DNA and similar genes in yeasts, fruit flies, and humans
anatomical and molecular homologies
similar forelimb anatomy in different species of mammals
anatomical and molecular homologies
HIV has become an important source of mortality for humans. If AIDS persists as a major factor for humans for many generations in the future, natural selection theory predicts that _____.
any heritable traits that help humans survive and reproduce in the presence of AIDS should become more frequent over time
The Galapagos Islands were the first place on Earth to _____.
be declared a world heritage site
Tourism on the Galapagos Islands is being restricted by requiring tourists to _____.
be escorted by trained guides at all times
resemblance of island species to nearby mainland species
biogeography
unique collection of marsupial mammals in Australia
biogeography
brown beetles survive to reproduce more than green beetles do. The brown allele increases in frequency.
change in population
the surviving insects reproduce. the frequency of insects in the population increases.
change in population
pesticide is applied to population of insects.
environmental change
The wing of a bat is homologous to the _____ of a whale.
flipper
discovery of bones from many different dinosaur species
fossil record
transitional forms that link whales with land-dwelling ancestors that are now extinct
fossil record
The ease with which humans travel across the globe is likely to increase _____.
gene flow
All the genes in a population are that population's _____.
gene pool
In a population with brown and green alleles for color, genetic drift
has more effect on the evolution of a small population.
Which species is threatening the natural wildlife on the Galapagos Islands?
humans
Where are the Solomon Islands located?
in the South Pacific
In a type of sexual selection often called ____________ , individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance or behavior of the male.
mate choice
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
metaphase I
Generation-to-generation change in the allele frequencies in a population is _____.
microevolution
The phrase Darwin used to describe his broad theory of evolution is ''descent with ____________.''
modification
Darwin proposed a mechanism for how evolution occurs, which he called ________________.
natural selection
a prominent tail helps the peacock attract a mate
natural selection
camouflage enables this insect to evade predators
natural selection
changes in average beak size in finches following dry or wet years
natural selection
development of pesticide resistance in insects
natural selection
the birds beak is well suited for cracking seeds
natural selection
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.
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.
Why did the biologists consider a frog that they found to be a new species?
Its call was unique.
The scientists who produced the herbicide warned against overuse, saying that over time, ____.
resistant weeds would increase in number
________________ favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation.
Stabilizing selection
The human immune system cannot effectively suppress the HIV virus on its own. What key feature of HIV makes it so hard to beat?
The HIV virus has an extremely high rate of mutation.
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.
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
Imagine that four people are infected with HIV from a common source (an infected blood sample). Initially, the patients' HIV populations are genetically identical. By the time they develop full-blown AIDS, how would the viral populations of the fourpatients compare?
Each patient's viral population would be unique, specifically adapted to deal with—and overcome—his or her unique immune system responses.
As proposed by Darwin, what sorts of traits are favored by natural selection?
Heritable traits that help individuals survive and reproduce more successfully than others in the same population.
Which of the following events could NOT be caused by a population bottleneck?
Increased population size
Which of the following statements about the amoeba population described at the end of the tutorial is true?
It is more vulnerable to extinction due to lack of genetic variation.
Based on the video, what can you infer about speciation--the process by which one species splits into two or more species?
Physical separation of populations is often part of the speciation process.
What does it mean to say that pigweed is resistant to herbicide?
Pigweed plants thrive despite the application of herbicides intended to kill them.
