selection

Question 1

selection

Answer 1

process by which organisms that are better adapted to their environment at the time survive breed while those that are not fail to breed

Question 2

directional selection

Answer 2

selection that favours individuals that vary in one direction from the mean of the population

changes characteristics from the mean
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Question 3

stabilising selection

Answer 3

selection favour average individuals

preserves the mean characteristics of a population
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Question 4

what factor produces a normal distribution curve

Answer 4

polygenes - most characteristics are influenced by more than 1 gene

the effect of the environment on these genes produces individuals in a population that vary about the mean

Question 5

directional selection - explanation

Answer 5

if environment changes so do the phenotypes - genotypes and alleles needed for survival

some individuals at extremes of the mean may be better suited to new conditions - more likely to survive breed alleles become more numerous others less numerous

over time the mean will move in the direction of the more numerous advantageous alleles

Question 6

how do population size remain constant despite over production on offspring

Answer 6

COMPETITION BET INDIVIDUALS 🐑🐏
those which are better adpated to their habitats survive reproduce passing on advantageous alleles to offspring

advantageous alleles increase in number and non advantageous alleles decrease in number

whats an advantage in one pop might not b in another

Question 7

The population of trees in the forest evolved adaptations to the mountain environment. Use knowledge of selection to explain how.

Answer 7

1. Variation in original colonisers / mutations took place;
2. Some better (adapted for) survival (in mountains);
3. Greater reproductive success;
4. Allele frequencies change;

Question 8

what selective determine

Answer 8

the spread of an allele within the gene pool

Question 9

3 types of selective pressure

Answer 9

directional
stabilising
disruptive

Question 10

Disruptive selection

Answer 10

enviromental conditions allow the mean to shift in 2 different directions as the individuals about the mean die out, no longer favoured, allowing the formation of 2 distinct means