ANTH Ch. 14

human and chimpanzee genomes are very similar; humans are more closely related to chimpanzees and bonobos than to any other apes; a small fraction of genes shows evidence of selection since the divergence of apes and humans

Recent genetic analyses have compared humans to other apes. Identify the correct findings from this research. -Human and chimpanzee genomes are very similar. -Humans are more closely related to chimpanzees and bonobos than to any other apes. -A small fraction of genes shows evidence of selection since the divergence of apes and humans. -Very few protein coding genes are different between humans and chimpanzees. -Noncoding DNA shows no evidence of selection since the chimpanzee-human divergence.

true

Researchers have shown that variation in some traits is due solely to genetics. true or false?

balanced morphism

Sickle-cell anemia in malarial environments leads to a ____________ _____________ because the heterozygote has a higher fitness than either homozygote.

positive

Since the split between the human line and the chimpanzee/bonobo line, there has been _________________ selection in noncoding sequences of DNA.

the original expansion out of Africa accounts for much of the genetic variation among human populations

The graph below compares genetic distance to geographic distance based on the likely pathway of expansion of humans out of Africa. What can be concluded from this graph? -There is no correlation between genetic distance and geographic distance. -The original expansion out of Africa accounts for much of the genetic variation among human populations. -Populations have less genetic distance as geographic distance increases. -The hypothesized pathway of expansion of humans out of Africa is not supported by these data.

regardless of time period, wealthier people are taller on average than those who have less money

The graph below shows the height of English boys versus their age for six different temporal and social populations. What can you conclude from this graph? (Note: English "public school" is the equivalent of American private school.) -Those involved in physical labor have greater stature than those not involved in physical labor. -Height decreases over time. -Social aspects, such as wealth, play no significant role in stature. -Regardless of time period, wealthier people are taller on average than those who have less money.

our environment

The high occurrence of non-insulin-dependent diabetes (NIDD) in some populations might be explained by recent and sudden changes in __________. -the prevalence of insulin-dependent diabetes -evolutionary processes that govern our biological change -our environment -mutation rates

complex phenotypic

height is an example of a __________ _________________ trait

vary in frequency among human groups

Diseases that are caused by genetic factors tend to __________. -vary mainly depending on skin color -vary in frequency among human groups -be distributed uniformly among human groups -be more common in one sex than the other

favorable mutation arises; individuals with favorable mutation have higher fitness; favorable mutation increases in frequency; these recently selected genes are surrounded by a long haplotype

Place in order the events that occur in a selective sweep. -Favorable mutation arises. -Favorable mutation increases in frequency. -Individuals with favorable mutation have higher fitness. -These recently selected genes are surrounded by a long haplotype.

Middle East, Northern Europe, Africa

A history of pastoralism has favored lactase persistence in the __________ ___________, _____________ ___________, and in (desert regions of) _____________

continuous variation

A popular political statement now is, "There is no such thing as race." I wonder what people think when they hear this. They would have to suppose that the speaker, if he were dropped by parachute into downtown Nairobi, would be unable to tell, by looking around him, whether he was in Nairobi or Stockholm. This could only damage his credibility. The visible differences between different populations tell everyone that there is something here. (p. 60) -physical characteristics -continuous variation -variation among groups -phenotype

environment influences stature; stature varies among human populations; many genes affect stature

Identify the correct statements regarding stature, a complex phenotypic trait. -Environment influences stature. -Stature varies among human populations. -Many genes affect stature. -Variation in stature among populations is primarily due to genetics. -Variation in stature is never adaptive.

selection

If heterozygotes for a certain gene have better increased fitness than homozygotes, variation can be maintained in a population by ______________________.

in using a small number of "races," forensic anthropologists will incorrectly identify individuals from populations such as the Middle East or India, with the potential for false identification of the deceased

Forensic anthropologists note that if we separate all of humanity into three groups (white, black, Asian), there are common traits within a group that are based on inherited genes from a common ancestor. Due to the necessity of their jobs, these forensic anthropologists attempt to determine "race" from skeletal remains. Which of the following is a valid criticism of this approach to skeletons and race? -There are no phenotypic differences among whites, blacks, and Asians. -Extensive gene flow in the modern world means that no genetic differences exist between human populations anymore. -In using a small number of "races," forensic anthropologists will incorrectly identify individuals from populations such as the Middle East or India, with the potential for false identification of the deceased. -Mendel's Law of Independent Assortment says that genes for dark skin and curly hair are as likely to be found in white and Asian populations as they are in black populations.

false (chimpanzees are)

Gorillas are the closest living relatives of modern humans. true or false?

ENVIRONMENTAL: modernization is associated with an increase in stature; people living in cold climates tend to have larger bodies than people living in warm climates GENETIC: "tall" alleles are more common in northern European populations, and "short" alleles are more common in southern European populations; thousands of genes have miniscule effects on height

Human stature varies within and among groups and is affected by both genetic and environmental factors. Identify which of the following pieces of evidence show that genetic factors influence height, and which show that environmental factors influence height. -"Tall" alleles are more common in northern European populations, and "short" alleles are more common in southern European populations. -Thousands of genes have miniscule effects on height. -Modernization is associated with an increase in stature. -People living in cold climates tend to have larger bodies than people living in warm climates.

races are cultural categories but do not represent natural biological categories; since humans vary, classification schemes can be used to group people together based on similarity

Identify the correct statements regarding race. -Races are cultural categories but do not represent natural biological categories. -Since humans vary, classification schemes can be used to group people together based on similarity. -Regardless of which physical trait is used, the same groupings, or races, of humans are found. -Most of the world's genetic variation is encompassed by racial classification schemes.

many of the genes that cause differences in phenotype may involve traits affected by genes at many loci; these differences could be the result of changes in regulatory genes, which cannot yet be identified; sometimes the change in only one or two base pairs in a DNA sequence can strongly affect phenotype

If humans and chimpanzees only differ by 1.2% genetically, why are there such sizable differences phenotypically between the two species? -The phenotypic differences are not caused by genetics. -Many of the genes that cause differences in phenotype may involve traits affected by genes at many loci. -These differences could be the result of changes in regulatory genes, which cannot yet be identified. -Sometimes the change in only one or two base pairs in a DNA sequence can strongly affect phenotype.

the adaptive advantage conferred by having one copy of the deleterious allele far outweighs the death toll of those with two copies

If natural selection is still at work in human evolution, why are fatal diseases such as sickle-cell anemia still widespread? -Natural selection only works on phenotypes, and people with sickle-cell anemia are not phenotypically different. -Dark skin protects people with sickle-cell anemia, letting them pass on their genes. -Even if natural selection eliminated the genes, recently eliminated alleles are likely to come back. -The adaptive advantage conferred by having one copy of the deleterious allele far outweighs the death toll of those with two copies.

false (100% chance. Tay-Sachs is a deadly condition that is expressed when two copies of the recessive allele are inherited.)

Individuals who are homozygous for the Tay-Sachs allele have a 50% chance of passing on the allele to their offspring. true or false?

true

Lactase persistence is selected for in populations that have a history of dairying. Lactase persistence is not favored in populations that do not have a history of dairying. true or false?

within: mutation, balanced polymorphism between: selection in different environments, lactase persistence

Match the causes of genetic variation with examples of variation both within groups and between groups. -mutation -balanced polymorphism -selection in different environments -lactase persistence

true

Measuring phenotypic similarities between twins can be used to estimate heritability. true or false?

false (mutation and natural selection can both maintain deleterious genes in a population)

Mutation is the only force of evolution that can maintain deleterious genes in a population. true or false?

heritability

The measure that computes the proportion of variation due to genetics is _____________.

true

There is no adequate racial classification that can be used to subdivide the human species. true or false?

tuberculosis

Those who are heterozygous for the gene that causes Tay-Sachs disease have the benefit of higher resistance to __________________.

variation at a single genetic locus

Which of the following is responsible for the variation in humans' ability to digest lactose? -a complex genetic polymorphism -the same gene that controls for skin color -the set of genes that also varies with resistance to malaria -variation at a single genetic locus

They make use of SNPs; they can be used to examine the genetic basis of complex traits; they can be used to estimate heritability, or the proportion of variation due to genetics

Which of the following statements regarding genomewide association studies are true? -They make use of SNPs. -They can be used to examine the genetic basis of complex traits. -They can be used to estimate heritability, or the proportion of variation due to genetics. -They can be used to assess how the environment affects complex traits.

very little of the world's genetic variation is explained by racial categories (Racial categories do not account for most of human genetic variation)

Why is the North American concept of race fundamentally flawed? -Very little of the world's genetic variation is explained by racial categories. -The differences between races are due to biological heritage. -Our species can be divided into a few distinct races based on genetics. -Race has nothing to do with disease susceptibility.

genetic drift

_________________ causes alleles to be more frequent in populations that have expanded from a single, typically small, founding population. -genetic drift -natural selection -balanced polymorphism -heterozygous advantage