Evolutionary Theory (7abcdef - 12b)

1. This cladogram shows the evolutionary relationships among some mammals based on homologous structures. Which statement is supported by the cladogram?

Hippopotamuses are more closely related to cows that to javelinas.

Toothed whales are more closely related to mouse deer than to hippopotamuses.

Javelinas and pigs are more closely related than baleen whales and toothed whales.

Cows and mouse deer are more closely related that javelinas and pigs.

The cladogram shows the evolutionary relationships among mammals based on homologous structures. It suggests that hippopotamuses and cows share a more recent common ancestor compared to hippopotamuses and javelinas. This is supported by the branching pattern in the cladogram, where the branch connecting hippopotamuses and cows is shorter than the branch connecting hippopotamuses and javelinas. Therefore, the statement "Hippopotamuses are more closely related to cows than to javelinas" is supported by the cladogram.

Explanation

The cladogram shows the evolutionary relationships among mammals based on homologous structures. It suggests that hippopotamuses and cows share a more recent common ancestor compared to hippopotamuses and javelinas. This is supported by the branching pattern in the cladogram, where the branch connecting hippopotamuses and cows is shorter than the branch connecting hippopotamuses and javelinas. Therefore, the statement "Hippopotamuses are more closely related to cows than to javelinas" is supported by the cladogram.

2. The data in the diagram is evidence that

A new species of horse suddenly appeared

Horses slowly developed over time

Horses have similar stages of rapid embryological development

Horses have a common ancestry with other hooved animals

The data in the diagram shows a series of stages in the embryological development of horses. This suggests that horses undergo a gradual process of development over time, rather than suddenly appearing as a new species. The diagram does not provide evidence for the sudden appearance of a new species or the common ancestry of horses with other hooved animals. Therefore, the most reasonable explanation is that horses slowly developed over time.

Explanation

The data in the diagram shows a series of stages in the embryological development of horses. This suggests that horses undergo a gradual process of development over time, rather than suddenly appearing as a new species. The diagram does not provide evidence for the sudden appearance of a new species or the common ancestry of horses with other hooved animals. Therefore, the most reasonable explanation is that horses slowly developed over time.

3. The aye-aye lemur is a mammal that feeds mostly on insect larvae that live inside trees. the aye-aye lemur has specialized middle finger that is long and thin. the aye-aye lemur moves along a tree branch and taps the branch with its specialized finger. When the aye-aye lemur hears a difference in the echo, it will tear open the bark with its teeth until the insect tunnel is exposed. The aye-aye lemur than uses its specialized finger to reach in the insect larvae and remove it. Which selective pressure most likely resulted in the development of the aye-aye lemur's special adaptation?

Limited availability of water

Competing for mates

Large numbers of natural predators

Food sources that are hard to find

The selective pressure that most likely resulted in the development of the aye-aye lemur's special adaptation is food sources that are hard to find. The aye-aye lemur's specialized finger and tapping behavior allow it to locate and access insect larvae that are hidden inside trees. This adaptation enables the lemur to overcome the challenge of finding and obtaining its primary food source, which is scarce and difficult to access.

Explanation

The selective pressure that most likely resulted in the development of the aye-aye lemur's special adaptation is food sources that are hard to find. The aye-aye lemur's specialized finger and tapping behavior allow it to locate and access insect larvae that are hidden inside trees. This adaptation enables the lemur to overcome the challenge of finding and obtaining its primary food source, which is scarce and difficult to access.

4. White-tailed deer are seasonal breeders. Female white-tailed deer begin their reproductive cycle in the fall. Rising testosterone levels in male white-tailed deer cause them to start their breeding season around the same time. Offspring are born the following spring and summer. What is the most likely explanation for white-tailed deer having a seasonal breeding cycle instead of a monthly breeding cycle like many domesticated animals?

Male and female deer come into contact with each other only in the fall.

Large predators are not found in deer habitats during the spring and summer months

Giving birth only in the spring and summer insures that offspring are born when food is most available.

Deer give birth in the spring and summer in order to avoid being pregnant during the hot summer months.

White-tailed deer have a seasonal breeding cycle instead of a monthly breeding cycle like many domesticated animals because giving birth only in the spring and summer ensures that offspring are born when food is most available. This strategy allows the deer to take advantage of the abundance of food resources during these seasons, increasing the chances of survival and growth for the offspring. By synchronizing their reproductive cycle with the availability of food, the white-tailed deer optimize their chances of successful reproduction and the survival of their young.

Explanation

White-tailed deer have a seasonal breeding cycle instead of a monthly breeding cycle like many domesticated animals because giving birth only in the spring and summer ensures that offspring are born when food is most available. This strategy allows the deer to take advantage of the abundance of food resources during these seasons, increasing the chances of survival and growth for the offspring. By synchronizing their reproductive cycle with the availability of food, the white-tailed deer optimize their chances of successful reproduction and the survival of their young.

5. Male guppies found in areas without predators are more colorful thatn the ones found in locations with large predator populations. A population of adult guppies orginating from an area with large number of predators is transferred to a nearby area with few predators. Which of these is most likely to happen over a few generations?

The morality rate of the guppies will increase.

Offspring will stop competing for resources.

There will be an increase in mutations in the offspring.

There will be an increase in the number of colorful guppies.

When the population of adult guppies from an area with large predator populations is transferred to an area with few predators, the selection pressure for dull coloration decreases. As a result, the guppies with more colorful traits have a higher chance of survival and reproductive success. Over a few generations, this selective advantage leads to an increase in the number of colorful guppies in the population.

Explanation

When the population of adult guppies from an area with large predator populations is transferred to an area with few predators, the selection pressure for dull coloration decreases. As a result, the guppies with more colorful traits have a higher chance of survival and reproductive success. Over a few generations, this selective advantage leads to an increase in the number of colorful guppies in the population.

6. A new predator of rabbits has been introduced within an ecosystem. This new predator runs faster than the native predators of rabbits. Which statement describes what will most likely occur in the rabbit population due to introduction of the predator?

The rabbits will mutate their genes and express genes that increase their speed.

Slower rabbits will develop stronger legs and pass this trait to their offspring.

Rabbits will mate and produce offspring with a different species that has faster runners.

Faster rabbits will survive and reproduce increasing the average speed of the rabbit.

With the introduction of a new predator that runs faster than the native predators, the slower rabbits will be at a disadvantage and more likely to be caught and killed. As a result, the faster rabbits will have a higher chance of survival and reproduction. Over time, this will lead to an increase in the proportion of faster rabbits in the population, ultimately increasing the average speed of the rabbit population.

Explanation

With the introduction of a new predator that runs faster than the native predators, the slower rabbits will be at a disadvantage and more likely to be caught and killed. As a result, the faster rabbits will have a higher chance of survival and reproduction. Over time, this will lead to an increase in the proportion of faster rabbits in the population, ultimately increasing the average speed of the rabbit population.

7. Conservation biologists studying cheetah populations have determined that the lack of genetic diversity among cheetahs is due to genetic drift. Which statement explains the most likely consequence of having a low genetic diversity on the cheetah population?

The chances of a mutation occurring in the cheetah population are decreased, increasing the cheetah survival rate.

The gene pool remains in equilibrium and future generations of cheetah offspring are stronger and better adapted to their environments.

The cheetah population becomes less likely to survive an outbreak of a disease or an environmental change, increasing the chance of species extinction.

Genetic variability is maintained from older cheetah populations that have survived and endured environmental stressors.

A low genetic diversity means that there is a limited range of genetic variation within the cheetah population. This lack of genetic diversity makes the population more vulnerable to diseases and environmental changes. With limited genetic variation, the cheetahs may not have the necessary genetic adaptations to withstand or adapt to new diseases or changes in their environment. This increases the likelihood of population decline and ultimately, species extinction.

Explanation

A low genetic diversity means that there is a limited range of genetic variation within the cheetah population. This lack of genetic diversity makes the population more vulnerable to diseases and environmental changes. With limited genetic variation, the cheetahs may not have the necessary genetic adaptations to withstand or adapt to new diseases or changes in their environment. This increases the likelihood of population decline and ultimately, species extinction.