BIOLOGY 1M03 Chapter Notes - Chapter 26: Mitosis, Reproductive Isolation, Meiosis

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coralmallard284

14 Dec 2012

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If mutation, natural selection and genetic drift cause isolated population to diverge sufficiently, distinct types of species, form. Speciation is the evolutionary process in which a new biological species arise: once speciation is complete, a new branch is added to the tree of life, begins when gene flow between populations is reduced or eliminated. Speciation results from genetic isolation and genetic divergence. Genetic isolation results from lack of gene flow. Divergence occurs because selection, genetic drift and mutation process independently in the isolated population. Species are distinct types of organisms and represent evolutionarily independent population or group of populations. Species are distinct from one another in terms of: behaviour, appearance, habitat use, other traits. Genetic distinction is due to mutation, natural selection and genetic drift. What makes one species evolutionarily independent of other species: answer: lack of gene flow. If gene flow between populations stops, then mutation, natural selection, and drift begins to act on the populations independently.

Related Questions

Which of the following statements best explains the process of allopatric speciation?

Genetic differences accumulate between populations that are isolated by a geographic barrier, eventually leading to reproductive isolation.

Genetic differences accumulate through recombination between populations that are interbreeding, eventually leading to reproductive isolation.

Genetic differences accumulate in a population through selective mate choice, leading to two groups that breed independently, causing reproductive isolation.

Two populations in the same geographical area accumulate genetic differences by random chance, eventually leading to reproductive isolation.

Genetic changes within a population as the result of genetic drift influences traits involved with mate choice, eventually leading to reproductive isolation.

What is the basic difference between allopatric and sympatric modes of speciation?

Sympatric speciation takes place between populations that migrate away from each other.

Sympatric speciation takes place between populations in the same geographic area.

Allopatric speciation takes place between populations in the same geographic area.

Sympatric speciation takes place over long periods of time; allopatric speciation occurs within a single generation.

Allopatric speciation is thought to occur much less frequently than sympatric speciation.

sangriaswan287

1. Scientists found that different beak shapes lead to differentmating songs in Darwin's finches. This result best supports whichhypothesis?

	A. Darwin's finches are not different species according to theBiological Species Concept.
	B. Behavioral isolation in Darwin's finches is unrelated to beakshape.
	C. Adaptation to different food sources likely occurred afterreproductive isolation in Darwin's finches.
	D. Adaptation to different food sources indirectly led tobehavioral isolation in Darwin's finches.

2. Which of the following could occur if two partiallyreproductively isolated populations become sympatric? Check allthat apply.

	A. Gene flow between the populations will occur
	B. The populations may eventually become separate speciesthrough reinforcement
	C. The populations will continue to be partially reproductivelyisolated
	D. The populations may eventually lose their geneticdistinctiveness
	E. Hybrids will be inviable or infertile

3. In which population would the rate of genetic drift be thegreatest?

	A large population that is geographically isolated from itsparent population
	A small population that is geographically isolated from itsparent population
	A large population that is not completely geographicallyisolated from its parent population
	A small population that is not completely geographicallyisolated from its parent population

4. Indicate true or false that the following organisms would beconsidered separate species according to the biological speciesconcept. (T/F)

1. Lions and tigers can interbreed successfully to produce viable,fertile offspring, but lions live in open grasslands and tigerslive in dense forests. (T/F)
2. Black bears in the United States can have coat colors rangingfrom blonde to jet black, but bears with different coat colorsoccupy the same habitat and interbreedsuccessfully. (T/F)
3. Many leopard frogs in the eastern United States look the sameand can mate to produce a fertilized egg, but the embryo does notdevelop past the early stages. (T/F)
4. Many of Darwin

cyanbuffalo931

Random, chance events that change allele frequencies are knownas:

A. Gene flow

B. Genetic drift

C. Natural selection

D. Balancing selection

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Question 21 pts

What type of selection acts to maintain the two extremephenotypic variants in a population?

A. Disruptive selection

B. Directional selection

C. Positive selection

D. Artificial selection

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Question 31 pts

Approximately, how much of our DNA is shared with our closestrelatives, chimpanzees?

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Question 41 pts

The large canines of male baboons are likely the result of________, while the fact that some male baboons are very colorfulis probably the result of _______.

A. Mutation; balancing selection

B. Gene flow; sexual dimorphism

C. Male competition; female choice

D. Mate choice; genetic drift

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Question 51 pts

Negative assortative mating results in an increased frequency ofhomozygous genotypes within a population.

True

False

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Question 61 pts

Genetic evidence suggests that humans and Neandertals neverinterbred.

True

False

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Question 71 pts

The specific variant of the FOXP2 gene associated with languageacquisition in humans is found in both humans and Neandertals.

True

False

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Question 81 pts

Industrial melanism describes the change in moth color from paleto dark after pollution from factories resulted in coating treetrunks with a layer of dark soot. Which statement is trueconcerning industrial melanism?

A. After pollution levels increased, all moths became darkercolored because soot got on their wings

B. The dark moths survived better after pollution levelsincreased because they were not poisoned by the pollutants

C. Individual moths changed their color in response to thepollution

D. Dark moths were present in the population before pollutionlevels increased

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Question 91 pts

Patterns of evolution can be seen above the species level

True

False

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Question 101 pts

Inbreeding is problematic because it increases the probabilitythat offspring inherit two copies of a recessive mutation thatcauses disease.