BIOL 1004 Lecture Notes - Lecture 7: Genetic Variation, Population Bottleneck, Microevolution

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salmondolphin972

15 Feb 2017

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It always occurs but effects are more noticeable in small populations. One important effect of drift on small populations is the loss of alleles from the. Loss of alleles by drift translate into a lower than expected (hardy-weinberg) frequency. Heterozigosity is a measure of the genetic diversity of a population. Genetic variation is essential for microevolution to occur. Mutations, selection (natural, artificial or sexual), genetic drift and gene flow can cause microevolution. Hardy-weinberg principles allows to test if a locus have been evolving in a population. Microevolution is the change in the allele frequencies in a population over generations. Genetic drift: process in which chance events cause unpredictable fluctuations in allele frequencies from one generation to the next. genepool. Losing an allele, losing a raw material that represents a gene. of heterozygotes in a population. Heterozigosity: frequency of heterozygotes individuals for a given locus in a population. Heteroz(cid:455)gotes al(cid:449)a(cid:455)s goes do(cid:449)(cid:374), (cid:272)a(cid:374)"t (cid:271)e (cid:373)ore tha(cid:374) 50%.

Related Questions

Q1. What are alleles?Different forms of the same gene.Different genes.The different characteristics of an organism.Genes found only in humans.Q2. If you add up the frequency of homozygotes + the frequency of heterozygotes for one gene (i.e. at one locus) in a population, what number do you get?Q3. People who are heterozygous for the sickle-cell allele:Are susceptible to malaria but not sickle-cell anemia.Are susceptible to sickle-cell anemia but not malaria.Are not susceptible to either sickle-cell anemia or malaria.Are susceptible to both sickle-cecell anemia and malaria.Q4. In the case study in this lab, which genotype is represented by "2pq" in the Hardy-Weinberg equation?Homozygous HbAHomozygous HbSHeterozygous HbA/HbSNo specific genotypeQ5. Suppose that, in an isolated village, the proportion of individuals that have sickle-cell anemia is 0.1 (or 1 of every 10 people). What proportion of the population should be sickle-cell carriers, according to Hardy-Weinberg expectations?Q6. When you simulated the elimination of malaria at the beginning of the lab, once the allele frequencies stabilized, what was the frequency of the HbA allele?Q7. When you investigated regional differences, what was the frequency (over many generations) of the HbS allele in the village in the "slightly wet" part of Africa?Q8. What is the number of deaths due to sickle-cell anemia in a region without mosquitoes expected to be?Very lowVery highModerateRelated to the frequency of malaria allelesQ9. As long as there are multiple alleles of a gene in a population, why will the frequencies of the alleles always change over time?Because natural selection changes all allele frequencies in populations over time.Because genetic drift causes random fluctuations of allele frequencies in populations.Because diseases will eliminate some of the alleles, generating fluctuations in their frequencies.Because allele frequencies fluctuate before the alleles eventually become fixed.Q10. Imagine a huge population with a gene that has ten functionally equivalent, neutral alleles. A small but genetically representative group of individuals from the big population is transported to an island, forming a small population. Which of the statements below best describes what will likely happen over time, and why?Because natural selection doesn't act on neutral alleles, the frequencies in the two populations should remain the same over time.Genetic drift will cause one allele to first become fixed in the island population, and later to become fixed in the original, large population.Genetic drift will result in the allele frequencies of the two populations diverging over time, with alleles being lost sooner in the island population.The allele frequencies of the two populations will change similarly due to a combination of genetic drift natural selection.

indigosnake469

____________________________ create new alleles in a population.

The change in allele frequency in a population over time is ____________________, not macroevolution, which refers to the formation of new ____________________.

Name one assumption (condition) that a population must satisfy to remain in Hardy-Weinberg equilibrium.

___________________________________________________________________

____________________ is the movement of alleles from one population to another due to migration.

_____________________ is a random change in allele frequency and has the greatest effect on ____________________ (small or large) populations.

The _____________________ of a population, resulting from some population crash, will cause the entire loss of some alleles due entirely to chance.

A type of genetic drift, known as ________________________________________, can cause rare alleles to become âcommonâ in the population, such as polydactyly in the Olde Order Amish populations.

Females prefer to mate with males who express certain traits. This is known as ____________________ and requires the two sexes to have different appearances (known as: ____________________ ____________________).

Which of the following statements is true about the theory of evolution?

The focus of the theory of evolution is to explain the origins of life.

According to the theory of evolution, life evolved entirely randomly.

The focus of the theory of evolution is to explain how life diversified from the first living cells.

According the theory of evolution, only the strongest and toughest can survive.

Which of the following best explains our current understanding of microevolution?

Neither microevolution nor macroevolution can be observed within a human lifespan?

Microevolution is the gradual change of the genetic makeup (allele frequency) of a population over time.

Microevolution and macroevolution occur by very different mechanisms

Microevolution is the evolution of small organisms; macroevolution is the evolution of large organisms.

The Irish elk is a giant species of deer that went extinct about 5,000 B.C. They are well-known for their extremely large antlers (12 feet wide) in males. The antlers likely played some role in protection against predators, but another possible cause for their large size could be

blending genetics

sexual selection

spontaneous generation

inheritance of acquired characteristics

Cross River gorilla is listed as critically endangered species. With only 35 of these gorillas in the world, they are at risk of extinction largely due to poaching and loss to diseases such as Ebola. Genetic studies of the remaining gorillas show very little variability, because several alleles were likely lost due to ______.

		genetic drift
		gene flow
		increased rate of spontaneous mutations
		adaptive radiation

BIOL 1004 Lecture Notes - Lecture 7: Genetic Variation, Population Bottleneck, Microevolution

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