BIOLOGY 1M03 Lecture Notes - Lecture 5: Allele Frequency, Aniridia, Geologic Time Scale

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cerisegiraffe538

21 Sep 2015

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Biology 1m03 - lecture 5 - evolution by natural selection. Evolution may be defined as changes in allele frequencies over time. There are exceptions, however, that depict evolution as much richer than merely changes in allele frequencies. Evolution by natural selection occurs when individuals with particular alleles (encoding particular traits) survive or reproduce more effectively than do their competitors in a population. An adaptation (at the microevolutionary scale) is a genetically based trait that increases a typical individual"s ability to survive and produce offspring in a particular environment. Evolution by natural selection is not progressive, and it does not change the characteristics of the individuals that are selected. It changes only the characteristics of a population. Animals do not always do things for the good of their species. Scientific theories are often made of observations about a natural pattern and a proposed process that explains that pattern. In the theory of evolution by natural selection, charles darwin and alfred.

Related Questions

Which statement about evolution by natural selection isfalse?

Natural selection allows organisms with higher fitness toreproduce more successfully.

Natural selection favors those traits that confer higherfitness in the environment.

Natural selection is a random change in characteristics of apopulation over generations.

Evolution by natural selection affects populations oforganisms, not individual organisms.

An organism's fitness depends on its _____.

ability to survive and reproduce

ability to swap genetic material with other organisms

physical size

ability to mutate

population

Consider the heavily armored stickleback fish population thatcolonized the lake. If all the individuals in that population weregenetically identical, what do you predict would happen when theycolonized the freshwater lake?

The population would increase, as it has increased foodresources.

The population would evolve through natural selection to bebetter adapted to its environment.

The population would decrease due to more juvenile fish beingeaten.

No answer text provided.

Which of the following are adaptations?

Thicker beaks on finches that allows them to eat large seeds,when large seeds are the most abundant.

Less armor on stickleback fish in freshwater that allows themto grow faster to avoid predation.

More armor on stickleback fish in the ocean that prevents themfrom being eaten by larger predators.

None of the above.

All of the above.

olivemink746

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.

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QuestionGroup: #31 Evolution

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Which of the below statements is NOT TRUE about human evolution?

While the total number of species that existed and the relationships among hominids is still unknown, some of the extinct hominids known today, however, are almost certainly direct ancestors of Homo sapiens.

Human evolution follows the mechanisms of natural selection.

Humans evolved from biological processes that are different from the processes that caused the development of other life forms on earth.

Many of the hominid species are close relatives, but not human ancestors.

Most hominids went extinct without giving rise to other species.

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QuestionGroup: #32 Evolution2

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______________ explains the process by which traits helpful in survival and reproduction become progressively more common in a population over the course of many generations.

Secondary metabolism

Darwinian theory of evolution

Evolutionary arms race

Biodiversity

Lemarkian theory of evolution

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QuestionGroup: #33 Natural selection

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Which of the following is considered to be "the most fit "from an evolutionary perspective?

a tiger who cares for his cubs, two of who live to adulthood.

a tiger who has a harem of many tigresses and one cub.

a tiger who is successful at capturing prey but has no cubs.

a tiger who has many cubs, twelve of which live to adulthood and they subsequently have cubs of their own.

a tiger who overcomes a new disease and lives to have four cubs.

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QuestionGroup: #34 Natural selection 2

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Which of the following is NOT a process of artificial selection?

(1),(2)

(1),(2),(3)

(1) Variation of traits within individuals

(2) Variation in some inheritable traits

(3) Breeders select animals with favorable traits

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QuestionGroup: #35 Evolution & us

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For bipedal movement in primates to occur, which anatomical changes had to take place?

The spine had to have a characteristic single curve

Thigh bone slopes outward from the hip to knee, placing feet under the center of gravity

The surfaces of the joints in legs and between vertebrae are enlarged

All of these are true regarding upright bipedal movement

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QuestionGroup: #36 Evolution & us2

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Neanderthal hominoids had which of the following characteristics?

To make art

Ability to speak

Ability to speak, make art, and were bipedal

Bipedalism

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QuestionGroup: #37 CNS

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Increasing the amplitude of a sound wave does what to the sound?

increases the amplitude

increases the decibels

Increases the harmonics

Increases the volume

Increases the pitch

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QuestionGroup: #38 CNS2

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Juan Manuel Marquez delivered a knockout punch to Manny Pacquiao. Manny cannot remember events that happened before the knock-out. What is this an example of?

Alzheimer's disease

Anterograde amnesia

Psychogenic amnesia

Retrograde amnesia

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QuestionGroup: #39 PNS

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The receptor hair cells in the cochlea respond to the frequency and amplitude of sound. Which group of receptors are most sensitive to sound?

Only those receptors that we normally do not use

Those that respond to low frequencies

Receptors respond equally to all frequencies.

Those that respond to high frequencies

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QuestionGroup: #40 Smooth/skeletal

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During skeletal muscle contraction where does ATP function?

Forms the cross bridges

Attaches to myosin

Causes the thick filaments to form thin filaments

Attaches to actin

BIOLOGY 1M03 Lecture Notes - Lecture 5: Allele Frequency, Aniridia, Geologic Time Scale

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