BIOL 1001 Chapter : Chapter 15

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azuremammoth471

15 Mar 2019

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If allele frequencies change from one generation to the next, the population is evolving. No mutations must occur in the population: 2. There must be no gene flow between populations: 3. The population must be very large: 4. If gene flow between populations of a species is blocked, the resulting genetic differences may grow so large that one of the populations becomes a new species: 3. In very small populations, drift can result in the complete loss of an allele in only a few generations, even if it is the more frequent one: there are two causes of genetic drift, a. 30,000: genetic analysis shows that present-day northern elephant seals are almost genetically identical, despite their numbers, their lack of genetic variation leaves them little flexibility to evolve if their environmental circumstances change, b. Natural selection (survival of the fittest: natural selection (ns) favors certain alleles at the expense of others.

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*Selection*	*Term*	*Description*
	Basal factors	a. bind to enhancers
	Activators	b. bind to promoters
	Coactivators	c. bind to activators
	Locus control region	d. large enzymatic complex found in the cytoplasm of alleukaryotic cells that down-regulates gene expression
	RISC	e. influences transcription from multiple genes linked over alarge region of DNA

*Selection*	*Term*	*Description*
	Gene pool	a. The process in which rare alleles increase in frequency in anew population
	Genetic drift	b. The sum total of all alleles carried in all members of apopulation
	Founder effect	c. The proportion of all copies of a gene in a population of aspecific type
	Evolutionary equilibrium	d. Unpredictable, chance fluctuation in allele frequency thathave a neutral effect on fitness
	Allele frequency	e. a balance between a new allele and selection against thatallele

champagnewallaby382

1. Humans and chimpanzees share several polymorphic loci. Which is the LEAST plausible explanation for this fact?

A. Balancing selection has maintained polymorphism in both species

B. Incomplete lineage sorting left polymorphic loci and those have persisted since the speciation event.

C. Interbreeding has allowed introgression of alleles at theses loci in both directions.

D. Genetic variation provided by the polymorphic alleles enhances resistance to pathogens.

2. According to the social brain hypothesis, we should expect primates living in larger social groups to have:

A. Larger brains, specifically, a neocortex of relatively larger size

B. Lager incisors and canines, to defend against more social competitors

C. Smaller brains, because many individuals can work together to solve problems

D. Great variation in brain and neocortex size, with the dominant individuals having the largest

3. You extract DNA from human bones in an ancient village buried by volcanic ash. You discover that there is an extremely high frequency of the LCT allele for lactase persistence. What might you reasonably conclude about the population?

A. This population is likely the source of the high frequency of the LCT gene in Northern Europe

B. The village could not be more than 4,500 years old

C. The members of this population likely used domesticated livestock for their milk

D. villagers had a diet rich in wheat or another domesticated crop

4. Why do populations father from Africa have more deleterious mutations in their genome?

A. Repeated bottlenecks and founder effects made drift more intense more often

B. Populations farther from Africa have been exposed to more mutagens in the environment

C. As people migrated over the globe they interbred with Neanderthals and Denisovans

D. The populations are younger, so purifying selection has not had time to purge delirious mutations from the populations.

yelloweel732

Hemoglobin and Fitness Instructions Directions: Neutral Evolution

1. Obtain 20 beans of two different colors (e.g., white and red). Count out 16 white and 4 red beans. The white beans represent the Hn allele and the red beans represent the Hs allele. This is the genetic makeup of your starting population. (Note: You can use any objects that can readily be categorized into two groups, such as coins, colored rocks, or paper clips.)

2.Calculate the frequency of both alleles [f(Hn) and f(Hs)] and record them in Table 1. In our experiment frequency is a measure of how many copies of a given allele exist in the gene pool (i.e., a proportion). Use decimal values. â¨

3.Arrange the beans into pairs. These pairs represent the genotype of each of 10 individuals in the population. Record the number of individuals with each genotype [f(Hn Hn), f(Hn Hs), and f(HsHs)] in Table 1. â¨

4.Now imagine that the individuals are living and reproducing with each individual reproducing at the same rate (i.e., all individuals produce two copies of each of their alleles into the next generation). Obtain enough beans to represent the next generationâ the offspring generationâand then let the parental generation âdieâ. â¨

5.Calculate the frequency of each allele in the offspring generation and record it in Table 1. â¨

Answer the questions that follow in Table 1. â¨

Table 1

	f(HnHn)	f(HnHs)	f(HsHs)	f(Hn)	f(Hs)
oiginal generation
offspring generation

Answer the following questions to help you understand the exercise:

What happened to the frequency of the common allele? â¨

What happened to the frequency of the rare allele? â¨

What happened to the frequency of the common and rare alleles when the starting frequencies were different from yours

What happens to allele frequencies from one generation to the next if there are no evolutionary forces acting on the population? â¨

greyotter669

BIOL 1001 Chapter : Chapter 15

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