Evolution: Natural Selection

Which scenario would most likely result in the extinction of one or more species? - The water temperature of a pond decreases slightly, and the members of the pond populations adapt to the change. - The conditions are abnormally dry for one season in a desert, resulting in the deaths of a few members of a snake population. - A predatory fish is introduced into a lake, resulting in a dramatic decrease in the populations of smaller fish. - A new plant species begins growing in a forest, resulting in a new food resource for many animal populations.

A predatory fish is introduced into a lake, resulting in a dramatic decrease in the populations of smaller fish.

A coastal forest was home to a type of burrowing rodent that was not found anywhere else in the world. A year ago, a species of large predator moved to the forest, but the rodents were able to escape by hiding in narrow underground tunnels. Recently, a hurricane flooded most of the forest. A few days later, scientists studying the area found that no members of this species remained. Which best describes why the species became extinct? - A natural disaster killed off the population by flooding their habitat. - Large predators moved to the area where the rodents lived. - They had no genetic variation so they could not adapt to changes in the habitat. - They were not big enough to compete with the new, larger species for food.

A natural disaster killed off the population by flooding their habitat.

___ is the total disappearance of all members of a species.

Extinction

Organisms must have variation within a population in order for natural selection to occur. Which situation is an example of this variation? - A frog living in a pond is eaten by a predator, while others in the same population survive. - A snake living in a desert produces more offspring than other snakes in the same population. - Some rabbits living in a forest have short, spotted ears, while others have long white ears. - Some birds living in a grassland eat less than other birds who eat the same food.

Some rabbits living in a forest have short, spotted ears, while others have long white ears.

Due to a genetic mutation, a mouse is born with fur that is not as light as fur in other mice of the same population. This makes it easier for the mouse to blend into the environment. How will this mutation most likely affect the mouse and the population? - The mouse with the mutation will not survive, and the trait will disappear from the population. - The mouse with the mutation will survive and reproduce, and the trait will spread over future generations. - The mouse with the mutation will not survive, but the trait will appear again in the next generation. - The mouse with the mutation will survive and reproduce, but the trait will disappear because it was caused by a mutation.

The mouse with the mutation will survive and reproduce, and the trait will spread over future generations.

A population of ducks lives in an area that floods many times each year. Some of the ducks are better at finding food on dry land, while other ducks are better at finding food in wet, muddy areas. Eventually, the land around the lake permanently changes from dry soil to wet, marshy mud. How will this change to the land most likely affect the duck population? - The population will remain stable because the ducks will not be affected by this kind of change. - The population will eventually balance out so that there are equal numbers of both types of ducks. - The population will evolve so that most ducks survive no matter how they find food. - The population will evolve so that most ducks are better at finding food in wet, muddy areas.

The population will evolve so that most ducks are better at finding food in wet, muddy areas.

What occurs if the environment changes and a species is no longer able to survive? The species becomes extinct. The species evolves. The species adapts. The species is naturally selected.

The species becomes extinct.

Many scientists believe that dinosaurs became extinct due to ____ floods caused by strong storms. a harmful genetic mutation. the introduction of a predator. an asteroid impact.

an asteroid impact.

When the environment changes, nature selects favorable ___. adaptations population sextinctions Over time, these ___ in a population. decline build up stay the same

build up

Each organism in a population produces more offspring than can survive. This is called __. variation adaptation overproduction

overproduction

Which statement describes how favorable traits in a population relate to natural selection? They are the only traits that ever exist in the population. They build in the population over time. They are rarely passed on to offspring. They are found only in a few individuals within the population.

They build in the population over time.

Explain how natural selection can lead to evolution.

- When the environment changes, organisms best suited for the new environment survive and reproduce. - The favorable adaptation is passed on to the next generation. - Over time, more and more organisms will have the favorable adaptation, and the population will evolve.

Several butterflies within a large population have wings with large dots on them. This wing pattern warns predators not to eat the butterflies. Which best describes the characteristic of having dotted wings? - favorable adaptation, which is one condition required for natural selection - unfavorable adaptation, which is passed on to offspring in all cases - favorable adaptation, which is passed on to offspring in very few cases - unfavorable adaptation, which is not a condition for natural selection

favorable adaptation, which is one condition required for natural selection

The process by which the organisms that are better adapted to the environment survive and reproduce is called ___. evolution natural selection extinction variation

natural selection

In order for natural selection to occur, populations must have ___. extinction variation predation

variation

Which example best illustrates a condition necessary for natural selection to occur? Cheetahs have nearly identical genetic makeup. Clownfish can lay a thousand eggs at a time. Some bacteria have very specific temperature requirements. A strawberry plant is able to reproduce asexually.

Clownfish can lay a thousand eggs at a time.

Which statement best describes how reproduction leads to natural selection in a population? - Organisms do not produce many offspring, so all of them can survive and pass on their traits. - Organisms overproduce offspring; consequently, all of them are likely to survive and pass on traits. - Organisms overproduce offspring, so only some survive and pass on their traits. - Organisms do not overproduce offspring; therefore, those that are produced will develop the best traits.

- Organisms overproduce offspring, so only some survive and pass on their traits.

Explain the relationship between mutations, adaptations, natural selection, and extinction.

- Adaptations result from random mutations in the genes of organisms. - Adaptations may be favorable or unfavorable depending on the environment. - If an adaptation is favorable, it is selected by nature and, over time, more and more organisms in a population will have it. - If the environment changes so much that the adaptations of a species are no longer enough for the species to survive, extinction will occur.

During natural selection, which organisms are most likely to survive as the environment changes? - ones that can best adapt to and survive in the changing environment - ones that can adapt to the original environment - ones that are randomly selected for survival independent of the environment - ones that are randomly selected for survival in the changed environment

- ones that can best adapt to and survive in the changing environment

Which is an example of an environmental influence that would most likely result in natural selection? - The soil in a field always has lots of nutrients, so corn plants in a population can grow quickly. - A fish is born with a genetic mutation that produces a longer tail, allowing the fish to swim faster than others in the population. - A food resource disappears in a pond, and some frogs in a population can eat the remaining food resource, while others cannot. - The temperature in a lake remains constant, so most of the turtle population survives to adulthood.

A food resource disappears in a pond, and some frogs in a population can eat the remaining food resource, while others cannot.

The mice living in an area changed from having brightly colored fur to having darkly colored fur. How did natural selection most likely result in this evolutionary change? - Bright mice were not able to blend into their environment as easily as dark mice, so they did not continue to survive and reproduce. - Bright mice produced fewer offspring than dark mice, so the bright mice became outnumbered within days. - Random changes in the genetics of bright mice produced more dark mice, so the bright mice quickly died off. - Random changes in the genetics of dark mice produced fewer bright mice, so the dark mice took over the population.

Bright mice were not able to blend into their environment as easily as dark mice, so they did not continue to survive and reproduce.

A population of rabbits inhabits an island that has an active volcano. The volcano erupted and covered the island destroying most of the food resources available for animals living in the area. As the island recovers, the soil no longer allows for these food resources to growing. How will this most likely affect the rabbit population on the island? - There will be fewer predators that eat the rabbits, so the rabbit population will quickly grow. - Other animals will eat less food, so the rabbit population will remain stable. - The rabbits will adapt to eating very little food, so the population will increase slowly over time. - Few rabbits will be able to find food, so the population will die off and become extinct.

Few rabbits will be able to find food, so the population will die off and become extinct.

There are green and red bugs living in an area. As a result of an environmental change, birds that live in the same area grow in numbers. These birds eat the bugs, and they prefer the taste of the red bugs. How will the increase in the bird population most likely affect the bug population? - Green bugs will survive better and reproduce, so the bug population will evolve into mostly green bugs. - Red bugs will survive better and reproduce, but the bug population will evolve into mostly green bugs. - Green bugs will survive better and reproduce, but the bug population will evolve into mostly red bugs. - Red bugs will survive better and reproduce, so the bug population will evolve into mostly red bugs.

Green bugs will survive better and reproduce, so the bug population will evolve into mostly green bugs.

A genetic mutation causes a squirrel to be born with much darker fur than its parents. How will this mutation most likely affect the squirrel population? - Because the trait was caused by a mutation, it will not be passed on to any offspring, resulting in the disappearance of the trait. - Because the trait was caused by a mutation, it will be passed on to offspring over many generations, resulting in a population of darker squirrels. - If the trait is unfavorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels. - If the trait is favorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.

If the trait is favorable, it will be passed on to offspring over many generations, resulting in a population of darker squirrels.

Which are characteristics of natural selection? Select three options. It affects populations. It affects only individuals. It occurs when there is genetic variation. It occurs when organisms are genetically identical. It selects organisms with certain traits to survive. It selects organisms at random to survive.

It affects populations. It occurs when there is genetic variation. It selects organisms with certain traits to survive.

Which conditions are required for natural selection? Select three options. Populations have genetic variation. Organisms overproduce offspring. Environmental conditions remain stable. Traits are passed on to only some of the offspring. Nature selects favorable adaptations.

Populations have genetic variation. Organisms overproduce offspring. Nature selects favorable adaptations.

In a mouse population, some mice have thicker fur than others, but there are more mice with thinner fur. The climate in which these mice live has slowly gotten colder. How will this change in the environment most likely affect the mouse population? - The adaptation of thinner fur will be selected over thicker fur, and the population will remain unchanged. - The adaptation of thicker fur will be selected over thinner fur, and the population will remain unchanged. - The adaptation of thinner fur will be selected over thicker fur, and the population will evolve. - The adaptation of thicker fur will be selected over thinner fur, and the population will evolve.

The adaptation of thicker fur will be selected over thinner fur, and the population will evolve.

Due to a genetic mutation, a deer is born with a missing toe. This makes it difficult for the deer to escape from predators. How will this mutation most likely affect the deer population? - The deer with the mutation will not survive, and the trait will disappear from the population. - The deer with the mutation will survive and reproduce, but it will not pass this trait on to its offspring. - The deer with the mutation will not survive, but the trait will appear again in the next generation. - The deer with the mutation will survive and reproduce, and the trait will commonly appear in future generations.

The deer with the mutation will not survive, and the trait will disappear from the population.

Why did the color of the peppered moth change? The moths' life cycle changed. The environment changed. The amount of variation in the moth population changed. The number of individual moths in the population changed.

The environment changed.

What caused natural selection among the peppered moths of Manchester, England? natural environmental changes human-caused environmental changes genetic stability in the population resource stability in the population

human-caused environmental changes

Which causes genetic variations and can result in different alleles? predation rate random mutations competition environmental changes

random mutations

A species of butterfly lives in a warm climate. The butterflies feed on the nectar of tropical flowers. Birds eat the butterflies, and they prefer to eat the butterflies with brighter wings. What would most likely cause this species to become extinct? a mutation resulting in darker wings a decrease in the birds that eat the butterflies the destruction of the butterflies' environment overproduction of butterfly offspring

the destruction of the butterflies' environment

If there are only a few remaining members of an insect species living in one area, which would most likely cause this species to become extinct? - the introduction of new predators to the insects' environment - a genetic mutation in an individual that causes it to be very small - a disease that causes a mother insect to die shortly after laying eggs - the introduction of a new food source to the insects' environment

the introduction of new predators to the insects' environment