GED Science : Evolution and Genetics

Study concepts, example questions & explanations for GED Science

varsity tutors app store varsity tutors android store

Example Questions

← Previous 1

Example Question #1 : Evolution And Genetics

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

Possible Answers:

Changing colors of a chameleon

Thorns on a rose bush

The long neck of a giraffe

Dogs with hypoallergenic fur

Correct answer:

Dogs with hypoallergenic fur

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.

Example Question #1 : Evolution And Genetics

Which of the following is an example of natural selection?

Possible Answers:

Organisms can only reproduce with other organisms of their species

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

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

Correct answer:

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

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.

Example Question #1 : Evolution And Genetics

Which of the following statements about alleles is correct?

Possible Answers:

Alleles represent different forms of the same gene

Humans have only one allele for each gene

A heterozygous genotype will have only one type of allele present

A homozygous genotype will have two different alleles present

Alleles represent the same forms of different genes

Correct answer:

Alleles represent different forms of the same gene

Explanation:

Alleles are different forms of the same gene. For example, the gene for flower color in a plant may come in two allele varieties: white or purple. Both alleles code for flower color (the same gene), but represent different types of the genetic expression.

Humans are diploid organisms, meaning that they carry two alleles for each gene, one from each parent. Organisms with two copies of the same allele are considered homozygous, while those with copies of two different alleles are considered heterozygous.

Example Question #61 : Biology And Life Sciences

What word is used to describe an organism with two copies of the same allele?

Possible Answers:

Hybrid

Carrier

Homozygous

Heterozygous

Correct answer:

Homozygous

Explanation:

When an organism has only one type of allele for a given gene, it is described as homozygous ("homo-" meaning one). Organisms can be either homozygous dominant, meaning they have two dominant alleles, or homozygous recessive, meaning they have two recessive alleles.

A heterozygote, or hybrid, has two different types of alleles for a given gene. When the dominant allele causes the recessive trait not to be represented in the phenotype, the organism is considered a carrier for the recessive trait.

Example Question #1 : Evolution And Genetics

What type of mutation is the least dangerous to an organism?

Possible Answers:

Missense mutation

Frameshift mutation

Silent mutation

Nonsense mutation

Correct answer:

Silent mutation

Explanation:

There are a variety of mutations that can affect how a protein product is made in the body. Of the options listed, a silent mutation is the only type that does not change the final protein product. In a silent mutation, the DNA sequence is changed, but the amino acid product remains the same. Because there is no change in functionality, a silent mutation cannot harm the organism.

All of the other types of mutations listed will change what the final protein looks like, and can affect the organism in a negative way.

Example Question #1 : Evolution And Genetics

Which type of mutation creates a new stop codon for the protein being created?

Possible Answers:

Missense mutation

Silent mutation

Frameshift mutation

Nonsense mutation

Correct answer:

Nonsense mutation

Explanation:

Nonsense mutations alter the position of the stop codon in the mRNA strand, which creates a different product. The result is a shorter polypeptide chain that may not be able to function.

Silent mutations do not alter the final protein product. A missense mutation causes an amino acid to be replaced by another, different amino acid. A frameshift mutation changes how the mRNA strand is read by the ribosome, resulting in a dramatically different product.

Example Question #1 : Evolution And Genetics

Which of the following statements is most accurate?

Possible Answers:

It is impossible to tell the evolutionary relationship between chimpanzees and humans without further fossil evidence

Humans are chimpanzees' most recent common ancestor

Chimpanzees and humans share a recent common ancestor

Chimpanzees are humans' most recent common ancestor

Correct answer:

Chimpanzees and humans share a recent common ancestor

Explanation:

Common ancestors are the branching points in a phylogenetic tree, from which multiple species originate. Chimpanzees and humans share a common ancestor. Through evolution, the genetic changes to this ancestor gave rise to two separate species: chimpanzees and humans. This divide occurred roughly 5 million years ago, according to fossil evidence.

To say that chimpanzees are the most recent common ancestor to humans implies that humans actually evolved from chimpanzees. Similarly, to say that humans are the most recent ancestor to chimpanzees suggests that chimpanzees evolved from humans. Neither of these statements are correct, as both species are actually derived from a shared ancient relative (the most recent common ancestor).

Example Question #62 : Biology And Life Sciences

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

Possible Answers:

Precambrian

Paleozoic 

Mesozoic 

Cenozoic 

Correct answer:

Cenozoic 

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."

Example Question #2 : Evolution And Genetics

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

Possible Answers:

No mutations entering the population

Large population numbers

Non-random mating

No new organisms entering the population

Correct answer:

Non-random mating

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.

Example Question #1 : Evolution And Genetics

What does it mean for a gene to be sex-linked?

Possible Answers:

It is a gene that only affects the reproductive structures of an organism

It is found in only one gender: either male or female

It is a gene located on the X or Y chromosome

It is located on autosomes

Correct answer:

It is a gene located on the X or Y chromosome

Explanation:

When a gene is sex-linked, it means that the gene is located on one of the sex chromosomes. These chromosomes are the X and Y chromosomes, with the Y chromosome only being found in males. Sex-linked genes provide the opportunity for the frequency of a phenotype to be seen more often in one gender than the other.

Sex-linked genes can be represented in either sex; if the trait is on the X chromosome, it can be displayed in both males and females but may appear more frequently in males.

← Previous 1
Learning Tools by Varsity Tutors