BIOC51H3 Chapter 3: chapter 3 notes

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olivemouse838

11 Feb 2012

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Artificial selection: domestic animals and plants y to increase the frequency of desirable traits in their stocks, plant and animal breeders employ artificial selection (example of darwin and his pigeon s on page 74). Evolution by natural selection y darwin realized that a process like artificial selection occurs in nature y his theory of evolution by natural selection suggests that descent with modification is the logical outcome of four postulates: Individuals within populations are variable y y the variations among individuals are, at least in part, passed from parents to y offspring. In every generation, some individuals are most successful at surviving and reproducing than others y the survival and reproduction of individuals are not random; instead they are tied to the variation among individuals. The individuals with the most favourable variations, those who are better at surviving and reproducing, are naturally selected.

Related Questions

A population may eventually stop responding to artificial selection because:

individuals in the population have become homozygous for the alleles responsible for the trait and natural selection is enhancing the results of artificial selection

individuals in the population have become homozygous for the alleles responsible for the trait and natural selection opposes any further change in the characteristic

individuals in the population have become homozygous for the alleles responsible for the trait

natural selection is enhancing the results of artificial selection

natural selection opposes any further change in the characteristic

yellowdolphin630

1. Traits don't necessarily have to be passed on from parent to offspring for natural selection to act on them; traits that are environmentally acquired during the life time of an individual (such as practicing to become very strong or very fast) can also be acted upon by natural selection. Select one: True or False

2.Within the same species and even within the same population, not all individuals are the same. They vary in size, shape or other traits.

Select one:

True

False

3.Differential reproductive success means that some individuals in a population leave more offspring that survive and reproduce relative to other individuals in a population.

Select one:

True

False

coraldolphin670

Corn (maize) was domesticated around 9,000 years ago through artificial selection. Ancient farmers selectively planted kernels from plants with desirable traits, such as bigger kernels, ease of harvest, and better taste. During this time, the wild ancestor of maize, teosinte, has been under natural selection that favors those traits that improve the chance of survival and reproduction in the wild. Maize and teosinte look different in many ways. Assign the following pairs of traits to their respective species by circling the correct response, then provide a hypothesis to explain why these traits were favored during natural or artificial selection in the space allotted.

Trait #1: In (maize or teosinte), the seed is encased in a hard fruit case. This trait may be favored during (artificial or natural) selection because __________________________________. In (maize or teosinte), the seed is exposed. This trait may be favored during (artificial or natural) selection because _________________________________________________.

Trait #2: In (maize or teosinte), the plant has one main stalk. This trait may be favored during (artificial or natural) selection because ___________________________________. In (maize or teosinte), the plant has many branches. This trait may be favored during (artificial or natural) selection because ____________________________________.

Trait #3: In (maize or teosinte), the ear breaks apart to release individual kernels at maturity. This trait may be favored during (artificial or natural) selection because ___________________________________________. In (maize or teosinte), the ear remains intact at maturity. This trait may be favored during (artificial or natural) selection because __________________________________.

2. If both maize and teosinte are grown in the wild, which species is more likely to proliferate? Why?

lavenderwoodchuck665

BIOC51H3 Chapter 3: chapter 3 notes

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