Intro to Physical Anthropology Chapter 14

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

1. favorable mutation arises 2. individuals with favorable mutation have higher fitness 3. favorable mutation increases in frequency 4. these recently selected genes are surrounded by a long haplotype

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 -noncoding DNA shows no evidence of selection since the chimpanzee-human divergence -very few protein coding genes are different between humans and chimpanzees -a small fraction of genes shows evidence of selection since the divergence of apes and humans

Correct Answer(s): -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 Incorrect Answer(s): -noncoding DNA shows no evidence of selection since the chimpanzee-human divergence -very few protein coding genes are different between humans and chimpanzees

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

Correct Answer(s): -many genes affect stature -environment influences stature -stature varies among human populations Incorrect Answer(s): -variation in stature is never adaptive -variation in stature among populations is primarily due to genetics

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

Correct Answer(s): -many of the genes that cause differences in phenotype may involve traits affected by genes at many loci -sometimes the change in only one or two base pairs in a DNA sequence can strongly affect phenotype -These differences could be the result of changes in regulatory genes, which cannot yet be identified Incorrect Answer(s): -the phenotypic differences are not caused by genetics

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

Correct Answer(s): -since humans vary, classification schemes can be used to group people together based on similarity -races are cultural categories but do not represent natural biological categories Incorrect Answer(s): -most of the world's genetic variation is encompassed by racial classification schemes -regardless of which physical trait is used, the same groupings, or races, of humans are found

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

Correct Answer(s): -they can be used to estimate heritability, or the proportion fo variation due to genetics -they can be used to examine the genetic basis of complex traits -they make use of SNPs Incorrect Answer(s): -they can be used to assess how the environment affects complex traits

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

Evidence of Environmental Influence on Height: -modernization is associated with an increase in stature -people living in cold climates tend to have larger bodies than people in warm climates Evidence of Genetic Influence on Height: -thousands of genes have miniscule effects on height -"tall" alleles are more common in Northern European populations, and "short" alleles are more common in Southern European populations

The graph below depicts the timing of 184 specific genes in the prefrontal cortex for chimpanzees, humans, and macaques. What can be concluded from this graph?

Expression of these genes is delayed in humans compared to other primates

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?

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

The graph below compares chest girth to average annual temperature. What can be concluded from this graph?

People living in warmer climates have narrower chests than people living in colder climates

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)

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

The figure below shoes the inheritance pattern of a condition known as specific language impairment (SLI) in a certain family tree. Circles are women and triangles are men. Blue indicates those exhibiting SLI, and red reflects those who do not exhibit SLI. Assuming that SLI is extremely rare in the population as a whole, what can you conclude from this family tree?

SLI is likely caused by a dominant gene, and most individuals with the condition are heterozygotes

Traits controlled by single genes can be considered simple traits, whereas those that are influenced by multiple genes as well as environment are complex traits. Identify each trait listed below as either simple or complex. -lactase persistence -skin color -height -sickle-cell anemia -Tay-Sachs

Simple: -lactase persistence -sickle-cell anemia -Tay-Sachs Complex: -skin color -height

The graph below shows the genetic index of African ancestry for carious contemporary populations that are the descendants of the African and Portuguese populations that inhabited Brazil. What can be concluded from this graph?

The Brazilian classification system of white, black and intermediate does not reflect genetic similarity within each group

If natural selection is still at work in human evolution, why are fatal diseases such as sickle-cell anemia still widespread?

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

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?

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

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

Variation BETWEEN Groups: -selection in different environments -lactase persistance Variation WITHIN a Group: -mutation -balance polymorphism

Why is the North American concept of race fundamentally flawed?

Very little of the world's genetic variation is explained by racial categories

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

balanced polymorphism

Height is an example of a _________ trait.

complex phenotypic

Consider the following pieces of evidence that might be used to suggest that people can be divided into races. What do these ways of classifying populations fail to take into account? 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)

continuous variation

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

false

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

false

Which continent's population (interconnected group of blue dots) would you expect to have the least genetic distance from East Africa's population? Which continent's population would you expect to have the greatest genetic distance? Drag and drop your answers to the appropriate continents.

greatest genetic distance continent of South America least genetic distance continent of Africa

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

heritability

The high occurrence of non-insulin-dependent diabetes (NIDD) in some populations might be explained by recent and sudden changes in _____________.

our environment

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

positive

The map below shows the distribution of skin color worldwide. Select the regions where you would find to expect the darkest skin color.

see image for numbers (numbers indicate possible answers) ANSWER: 3. (Africa) and 6. (Australia)

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

selection

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

true

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

true

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

true

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

tuberculosis

Which of the following is responsible for the variation in humans' ability to digest lactose?

variation at a single genetic locus