BIOL108 Chapter Notes - Chapter 23: Sexy Son Hypothesis, Frequency-Dependent Selection, Heterozygote Advantage

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turquoisemouse656

26 Oct 2018

School

University of Alberta

Department

Biology (Biological Sciences)

Course

BIOL108

Professor

Cynthia Friedman

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BIOL108 Full Course Notes

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Microevolution is the evolution on a smaller scale. The gene pool is made up of all the possible alleles of a population. If o(cid:374)e of the follo(cid:449)i(cid:374)g co(cid:374)ditio(cid:374)s are(cid:374) t (cid:373)et, e(cid:448)olutio(cid:374) ca(cid:374) occur. No (cid:373)utatio(cid:374)s, (cid:374)o(cid:374) ra(cid:374)do(cid:373) mating, no gene flow, no genetic drift, and no mutation. The relative fitness is the contribution an organism makes to the next generation relative to other organisms in that population. Sexual selection is a form of natural selection where in certain individuals are more likely to secure potential mates than are other individuals. Sexual selection results in sexual dimorphism, the difference in secondary characteristics between two sexes. Intrasexual selection refers to competition between the same sex, and intersexual selection refers to competition between the sexes. Females select partners based on the good genes hypothesis. Here is why natural selection cant engineer perfect organisms:

Related Questions

Which of the following is most likely as a population goes through a bottleneck?

Heterozygosity decreases because genetic distance increases.

Genetic diversity increases because mutation rate increases while the population is going through the bottleneck

. Genetic diversity decreases because some alleles can be lost as the number of individuals dwindles

. The proportion of individuals that are heterozygous increases because there are fewer individuals.

2)What is meant when it says that genetic drift produces "non-adaptive" evolution?

Sometimes natural selection can favor a trait that is good for the current conditions, but when conditions change it is no longer helpful.

Evolution is just a genetic change in a population. If genes are lost from a population due to chance (i.e. genetic drift), that may not be adaptive, meaning the remaining organisms are no more fit.

Evolution isn't perfect, and sometimes it makes mistakes.

whitekoala529

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

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

BIOL108 Chapter Notes - Chapter 23: Sexy Son Hypothesis, Frequency-Dependent Selection, Heterozygote Advantage

BIOL108 Full Course Notes

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