Natural Selection Study Island
Which of the following are main tenets of Darwin's theory of natural selection?
- The traits within a population vary and are heritable. - Individuals most adapted to their environments have a better chance of surviving to reproduce. - Individuals compete for resources. - Individuals can produce more offspring than can survive.
Which of the following may have been an advantageous adaptation for the jackrabbit?
- long ears to help them detect potential predators - strong Achilles tendons in their hind legs to help them move more swiftly
Speciation is the process by which new species are formed. Which of the following circumstances is most likely to lead to speciation?
A population becomes separated by environmental factors into two groups that do not reproduce with one another.
Which of the following statements describes an example of natural selection?
An aloe vera plant possessing a trait for extra thick leaves survives a long drought in a desert, while an aloe vera plant that has thinner leaves does not.
Severe flooding in an area caused a population of minnows to become split into two separate ponds. Prior to the separation, the male minnows all had a moderate number of spots. Following the separation, the first pond was filled with larger fish that fed on minnows, so male minnows with fewer spots were better able to avoid detection by predators. The minnows in the second pond, however, had very few predators, and female minnows in this pond preferred to mate with males that had the most spots. After many generations, the two minnow populations evolved into different species and could no longer interbreed.
Different selective pressures were acting upon the two populations, leading to an increase in genetic variation and the formation of two new species.
Severe flooding in an area caused a population of minnows to become split into two separate ponds. Prior to the separation, the male minnows all had a moderate number of spots. Following the separation, the first pond was filled with larger fish that fed on minnows, so male minnows with fewer spots were better able to avoid detection by predators. The minnows in the second pond, however, had very few predators, and female minnows in this pond preferred to mate with males that had the most spots. After many generations, the two minnow populations evolved into different species and could no longer interbreed. Which of the following best describes why the two minnow populations evolved into separate species?
Different selective pressures were acting upon the two populations, leading to an increase in genetic variation and the formation of two new species.
The woolly mammoth was a relative of modern elephants that lived in the cold, northern parts of the world less than five million years ago. Mammoths in warmer parts of the world lacked the warm, shaggy fur the woolly mammoth developed. Which of the following sentences best describes how natural selection resulted in the woolly mammoth?
Mammoths with thicker fur were more successful at surviving and reproducing in cold climates.
A scientist shines low levels of ultraviolet radiation on a dish containing colonies of ruby-red bacteria. He then makes several replicate plates from this dish over many generations. He finds that in addition to the ruby-red color, there are also pink, orange, and yellow bacteria. Which of the following is the best explanation for these findings?
Mutations occurred in the gene for color of the bacteria, which were passed on to successive generations.
All organisms that sexually reproduce exhibit behavior that prompts reproductive activities with the opposite sex. Why would this form of behavior most likely be naturally selected?
Organisms that have behaviors that encourage reproduction would be more likely to reproduce.
Which of the following is the most likely side effect of the overusage of pesticides?
Pesticide-resistant pests will survive, reproduce and flourish.
Which of the following is the most likely explanation for the difference?
Some change in the environment selected for red and blue lizards, but against green ones.
In 1943, drug companies began mass-producing penicillin. At that time, it was a medical miracle and was used as a remedy for infected wounds, pneumonia, and other bacterial diseases. Just four years later, however, it was no longer effective on the same diseases that it had previously been able to cure. What happened?
Some of the bacteria mutated to become resistant to penicillin.
The figure above shows plates made from a culture growing bacteria during specified generations. The culture has white and dark bacteria. After generation 1, scientists applied an experimental drug intended to kill the bacteria and kept the experimental drug in the culture during successive generations. Which statement best explains the results of the experiment?
The dark bacteria showed resistance to the drug.
A particular environment has enough food to support 50 rats through the winter. At the end of winter one year, there are 25 female rats and 25 male rats. Each of the 25 females gives birth to several litters of 3-6 pups each. In the fall, there are 300 rats. Ignoring the effects of predators and disease, what will happen to this population of rats between fall and the next spring?
The fifty rats best able to get and keep food will survive to reproduce next spring.
Which of the following best explains how genetic recombination influences evolution?
The genetic variation introduced during recombination provides new allelic combinations for natural selection to act upon.
A population of mammals originally lived in a certain area surrounded by land. Then, some of the organisms were taken to an island. These two populations remained separated for hundreds of years. Which of the following is most likely true of the organisms within the populations?
The organisms on the island are slightly different than those on the mainland.
Peppered moths use the adaptation of camouflage as protection from predators. They may have a variety of colors or shades, but before the Industrial Revolution, they were typically white with black speckles. The Industrial Revolution in the 1880s introduced large-scale pollution into the environment. The pollution resulted in widespread, dark-colored staining of buildings and trees. Which of the following was the most likely effect of the Industrial Revolution on peppered moths in cities?
The population of light-colored moths decreased and the population of dark-colored moths increased.
Over the years, bacteria have become less sensitive to antibiotics used for medicinal and sanitation purposes. This lack of sensitivity is termed antibiotic resistance. How is antibiotic resistance an adaptation?
The trait giving bacteria antibiotic resistance has become common, giving bacteria with the trait a selective advantage.
Natural selection allows a species to change in response to its environment. What is the process by which a species becomes better suited to its environment called?
adaptation
Genetic variation occurs in all organisms. Bacteria that cause ear infections, for example, are genetically similar and produce the same effect, but some variations may exist such that some of the bacteria might be resistant to antibiotics, while others are not. Which of the following would increase the antibiotic resistant bacterial populations?
an overusage of antibiotics
Speciation is the process by which new species
are formed
The source of genetic variation that occurs during meiosis and results in new combinations of alleles is known as _______.
genetic recombination
Field mice are sexually-reproducing organisms. In a population of field mice, traits that promote survival and reproduction are likely to ________ over time. Traits that do not promote survival and reproduction are likely to _______ over time.
increase, decrease
Organisms with traits that are well-suited to an environment tend to survive and reproduce at a greater rate than organisms that are less suited to an environment. This phenomenon is known as _______.
natural selection
Several bacterial colonies are placed on a petri dish that contains agar with antibiotics. After 24 hours, ninety percent of the original bacterial colonies die, but the remaining ten percent survive and later reproduce. Which of the following theories is demonstrated by this experiment?
natural selection
The molecular and structural similarities observed among these organisms is best explained by which of the following?
natural selection
When a bacterial infection is treated with an antibiotic, the hope is that the antibiotic will kill all of the bacteria and prevent them from reproducing. However, if the full prescription of antibiotics is not taken by the sick person, some of the more resistant bacteria can survive. When they reproduce, these bacteria can pass the genes responsible for their resistance on to their offspring. As a result, subsequent administration of the same antibiotic will be less and less effective over time. The information presented above suggests that antibiotic resistance is the result of
natural selection
Which of the following processes would be most effective in changing the frequency of certain traits in a population over time?
natural selection
An earthquake creates a chasm that separates a population of squirrels. The two populations of squirrels evolve into two separate species. What is the name of the process by which isolated populations of the same species become new species?
speciation
Which of the following resulted from a genetic variation that was favored by natural selection?
the long neck of a giraffe
Natural selection operates on populations over many generations. Which of the following allows natural selection to occur?
the unequal ability of individuals to survive and reproduce
Speciation occurs during the evolutionary development, or phylogeny, of a species. In which of the following situations can speciation occur?
when two populations are reproductively isolated