Question 1

Dr. Pohlson is studying the heritability of self-confidence. Because all of his research participants are upper-middle class adolescents from the same private school in New York City, the heritability of self-confidence will appear to be

Accepted Answer

Heritability estimates can be inflated when the sample lacks environmental diversity. Since Dr. Pohlson's participants are all from a similar socio-economic background and educational environment, any differences in self-confidence are more likely to be attributed to genetic differences rather than environmental ones, making heritability appear high.

Question 2

Heritability takes into account

Accepted Answer

Heritability is a statistical estimate that describes how much of the variability of a trait within a population can be attributed to genetic factors and how much to environmental factors. Therefore, heritability takes into account both genetic and environmental factors.

Question 3

Georgie and Lennie are identical twins. Which of the following is true of their genetic makeup?

Accepted Answer

Identical twins like Georgie and Lennie have identical genotypes because they come from the same fertilized egg that split into two. However, their phenotypes, which are influenced by both their genetics and environmental factors, may not be identical. Differences in environment, experiences, and random biological processes can lead to variations in their physical appearance, health, and other traits.

Question 4

In what way does epigenetic change alter the development of a given person's phenotype?

Accepted Answer

Epigenetic changes modify the activity of genes without altering the DNA sequence itself. They influence gene expression by turning genes on or off, thereby affecting the production of proteins that determine cell function and contribute to an organism's phenotype. This does not involve changing the genetic code, matching of sperm and egg cells, enhancing gene "strength," or causing genes to work singularly to produce a phenotype.

Question 5

Dr. Mahr is studying the heritability of shyness. Because her research participants are adolescents from different socioeconomic groups across the county, the heritability of self-confidence will appear to be

Accepted Answer

The heritability of self-confidence may vary depending on the environmental factors such as socioeconomic status, and therefore appear low.

Question 6

Which example best illustrates the concept of epigenetics?

Accepted Answer

Epigenetics involves changes in gene expression without altering the DNA sequence itself. Identical twins like Josh and Jason have the same DNA, but environmental factors and lifestyle choices can lead to differences such as height, illustrating epigenetics.

Question 7

The study of gene-environment interactions in the production of phenotype is called

Accepted Answer

The study of gene-environment interactions in the production of phenotype is known as epigenetics. This field addresses how environmental factors can affect gene expression and how that expression can result in different phenotypic outcomes.

Question 8

What is an argument against using adoption studies for assessing the relative influences of genetics and environment on child development?

Accepted Answer

Adoptive parents often undergo a thorough screening process to ensure they can provide a stable and supportive environment, which can reduce the variability in environmental factors that the study aims to measure alongside genetic factors. This can make it difficult to isolate the effects of genetics from the effects of environment, as the environments may be less diverse than in the general population.

Question 9

Which scenario best illustrates the concept of natural selection?

Accepted Answer

Natural selection is the process by which organisms with advantageous traits are more likely to survive and reproduce, passing on those traits to their offspring. In this scenario, those with sickle cell anemia are resistant to malaria, giving them a survival advantage in regions where malaria is prevalent. This leads to the gene for sickle cell anemia being passed down to future generations through natural selection.

Question 10

Heritability of most human traits is typically in the range of

Accepted Answer

Heritability estimates for most human traits fall into the moderate range, typically between 0.30 and 0.60. This suggests that both genetic and environmental factors contribute significantly to these traits.

Question 11

Because looking for candidate genes for particular phenotypes does not result in complete findings, contemporary functional geneticists often use

Accepted Answer

Genomewide association studies (GWAS) are commonly used by functional geneticists to identify genetic variations associated with specific diseases or traits. This approach allows researchers to scan complete sets of DNA, or genomes, of many individuals to find genetic markers that can help predict the presence of a disease or a trait, overcoming the limitations of candidate gene approaches.

Question 12

Why does Huntington's disease have a heritability ratio of 1.0?

Accepted Answer

Huntington's disease has a heritability ratio of 1.0 because it is a genetic disorder caused by a specific dominant gene mutation. If an individual inherits this gene, they will inevitably develop the disease, indicating that the trait is entirely determined by genetics with no environmental influence.

Question 13

The process by which survival and reproduction pressures in the wild have an effect on mating is referred to as

Accepted Answer

Natural selection is the process by which survival and reproduction pressures in the wild have an effect on mating. This process leads to the selection of traits that are advantageous for survival and reproduction, and these traits become more common in the population over time. Coercive inheritance, randomized lineage, and genetic exclusion are not terms used to describe this process.

Question 14

Two groups of students (Group A and Group B) participate in standardized agility tests. The results show that Group A is considerably more agile than Group B and that agility is heritable. What can we conclude?

Accepted Answer

If agility is heritable, it means that genetic factors play a role. However, we cannot conclude anything about genetic variability between or within the groups or the effect of the environment on agility based on the information given.

Question 15

The heritability ratio of having a liver is

Accepted Answer

The heritability ratio of having a liver is 0.0 because having a liver is not a trait influenced by genetic variation among humans; it is a basic characteristic of human anatomy that all healthy individuals possess, regardless of their genetics. Heritability ratios are used to describe the extent to which genetic differences among individuals contribute to individual differences in observable traits, and since having a liver is not variable among healthy individuals, its heritability is zero.

Question 16

What do modern biologists describe as the "descent with modification from a common ancestor"?

Accepted Answer

"Descent with modification from a common ancestor" is the definition of evolution, as modern biologists describe it. Genetic lineage and heritability are related concepts, but they do not fully encompass the evolutionary process. The human genome is a specific example of genetic material, but it is not a comprehensive description of the broader concept of evolution.

Question 17

What allows for variation within the human species?

Accepted Answer

Alleles are different versions of the same gene, and they allow for variations within the human species. Alleles can lead to differences in physical traits such as eye color, hair color, and height, as well as differences in health outcomes and susceptibility to diseases.

Question 18

A new field known as _____ has emerged to explore the epigenetic influences of diet.

Accepted Answer

Nutrigenomics is the field that explores the ways in which diet can influence gene expression through epigenetic mechanisms. Option A refers to the study of genetic variation in response to dietary components; option B is not a recognized term; and option D refers to the study of genomic changes in cancer cells.

Question 19

In one study, rats licked frequently during infancy by their mothers were calmer than rats licked infrequently when faced with stress later in life. What is the most likely explanation for this difference?

Accepted Answer

The most likely explanation is that the licking behavior of the mothers influenced the expression of genes in their pups, affecting their responses to stress hormones. This epigenetic mechanism has been observed in studies, where maternal care can lead to long-term changes in gene expression related to stress responses.

Question 20

Which early scientist was the first to develop a method to account for variations observed in particular traits?

Accepted Answer

Gregor Mendel was the first scientist to develop a method to account for variations observed in particular traits, which he studied in pea plants and described as the principles of inheritance. Darwin, Galton, and Watson made significant contributions to the field of genetics and evolution, but did not develop the specific method of accounting for variations in traits that Mendel did.

Quiz 3: The Evolving Mind Nature and Nurture Intertwined