Evolution and Genetics

Help Questions

GED Science › Evolution and Genetics

Questions 1 - 10
1

Which of the following is not a result of natural selection?

Dogs with hypoallergenic fur

The long neck of a giraffe

Changing colors of a chameleon

Thorns on a rose bush

Explanation

In the case of the giraffe, chameleon, and rose, the species naturally adapted in order to survive. However, in the case of the dogs, there was intervention by man. Certain species and individuals were crossed to select for the desired genes that result in hypoallergenic fur, allowing the dogs to be kept by owners who would otherwise be allergic. Therefore, the dogs are an example of ARTIFICIAL selection, while the other choices demonstrate NATURAL selection. Natural selection is also referred to as survival of the fittest.

2

Which of the following is not a result of natural selection?

Dogs with hypoallergenic fur

The long neck of a giraffe

Changing colors of a chameleon

Thorns on a rose bush

Explanation

In the case of the giraffe, chameleon, and rose, the species naturally adapted in order to survive. However, in the case of the dogs, there was intervention by man. Certain species and individuals were crossed to select for the desired genes that result in hypoallergenic fur, allowing the dogs to be kept by owners who would otherwise be allergic. Therefore, the dogs are an example of ARTIFICIAL selection, while the other choices demonstrate NATURAL selection. Natural selection is also referred to as survival of the fittest.

3

Which of the following contribute most to evolution in a population?

Non-random mating

Large population numbers

No mutations entering the population

No new organisms entering the population

Explanation

A population will not experience evolution if all of the following requirements are met:

1. Very large population numbers.

2. No new mutations entering the population.

3. No new organisms entering the population and changing the gene pool.

4. All mating is random.

5. No natural selection.

These tenets are the foundation of Hardy-Weinberg equilibrium. If mating is no longer random, evolution will take place in the population. Similarly, if mutations occur, new organisms enter the population, the population size is small, and natural selection is in effect, then evolution will be enhanced.

4

Which of the following contribute most to evolution in a population?

Non-random mating

Large population numbers

No mutations entering the population

No new organisms entering the population

Explanation

A population will not experience evolution if all of the following requirements are met:

1. Very large population numbers.

2. No new mutations entering the population.

3. No new organisms entering the population and changing the gene pool.

4. All mating is random.

5. No natural selection.

These tenets are the foundation of Hardy-Weinberg equilibrium. If mating is no longer random, evolution will take place in the population. Similarly, if mutations occur, new organisms enter the population, the population size is small, and natural selection is in effect, then evolution will be enhanced.

5

Which of the following is an example of natural selection?

Prairie dogs with darker fur colors get eaten more often by predators than prairie dogs with lighter fur

A falling rock crushes half of the flowers on a hill, but leaves the other half alive

Dogs are groomed by humans for desired traits

Organisms can only reproduce with other organisms of their species

Explanation

Natural selection is when nature makes certain traits more common due to their inherent advantage in a given environment. When a prairie dog is better hidden based on its fur color, that color will become more common over time as the darker fur colors are eaten away by predators. Humans can also make certain traits more common over time, such as in dogs, but this is an example of artificial selection, not natural.

6

Which of the following is an example of natural selection?

Prairie dogs with darker fur colors get eaten more often by predators than prairie dogs with lighter fur

A falling rock crushes half of the flowers on a hill, but leaves the other half alive

Dogs are groomed by humans for desired traits

Organisms can only reproduce with other organisms of their species

Explanation

Natural selection is when nature makes certain traits more common due to their inherent advantage in a given environment. When a prairie dog is better hidden based on its fur color, that color will become more common over time as the darker fur colors are eaten away by predators. Humans can also make certain traits more common over time, such as in dogs, but this is an example of artificial selection, not natural.

7

What does it mean to say that two genes are linked?

Both genes are on the same chromosome

Both genes are always expressed in an organism at the same time

Both genes are used for the same function in the organism

The genes are directly next to each other

Explanation

There are only 23 chromosome pairs in human beings, but there are thousands of genes. This means that many genes will be found on the same chromosome. When two genes are found on the same chromosome, they are said to be linked. Genes that are very close to each other on the chromosome are more likely to travel with each other to the same haploid cell during meiosis, and are frequently inherited together.

An example of linked genes are blue eyes and blond hair. These traits are frequently inherited together because they are found in the same region on the same chromosome.

8

What does it mean to say that two genes are linked?

Both genes are on the same chromosome

Both genes are always expressed in an organism at the same time

Both genes are used for the same function in the organism

The genes are directly next to each other

Explanation

There are only 23 chromosome pairs in human beings, but there are thousands of genes. This means that many genes will be found on the same chromosome. When two genes are found on the same chromosome, they are said to be linked. Genes that are very close to each other on the chromosome are more likely to travel with each other to the same haploid cell during meiosis, and are frequently inherited together.

An example of linked genes are blue eyes and blond hair. These traits are frequently inherited together because they are found in the same region on the same chromosome.

9

Which era is referred to as "the age of the mammals?"

Cenozoic

Mesozoic

Paleozoic

Precambrian

Explanation

There are three eras that divide geologic time: the Paleozoic era, the Mesozoic era, and the Cenozoic era. The Mesozoic era was the age of the dinosaurs. Following their extinction, the Cenozoic era began and mammals started to dominate the landscape. This gives the Cenozoic era the nickname "the age of the mammals."

10

Which era is referred to as "the age of the mammals?"

Cenozoic

Mesozoic

Paleozoic

Precambrian

Explanation

There are three eras that divide geologic time: the Paleozoic era, the Mesozoic era, and the Cenozoic era. The Mesozoic era was the age of the dinosaurs. Following their extinction, the Cenozoic era began and mammals started to dominate the landscape. This gives the Cenozoic era the nickname "the age of the mammals."

Page 1 of 3