9.4 types of selection

Question 1

what is selection?

Answer 1

process by which organisms that are better adapted to their environment tend to breed & survive

Question 2

what does a polygene characteristic mean?

Answer 2

charactistic is controlled by 1+ gene

Question 3

when does directional selection occur?

Answer 3

during environmental changes

Question 4

what individuals do directional selection select for?

Answer 4

phenotype more suited to environmental pressure

Question 5

towards which direction will the distribution curve shift towards when a specific allele is selected for?

Answer 5

towards their direction

Question 6

describe the environment when stabilising selection occurs.

Answer 6

stable & unchanging

Question 7

which individuals are selected against in stabilising selection?

Answer 7

both extremes

Question 8

how will the curve change during stabilising selection?

Answer 8

narrowing of curve

Question 9

give an example of anatomical adaptation.

Answer 9

short ears & thick fur in arctic foxes

Question 10

give an example of physiological adaptation.

Answer 10

kangaroos oxidise fat to produce water in dry desert

Question 11

what are physiological adaptations related to?

Answer 11

chemical reactions

Question 12

give an example of behavioural adaptation.

Answer 12

migration

Question 13

what is the founder effect?

Answer 13

reduction in genetic variation
when a small preset of a large population is used to establish a new colony

Question 14

what is a genetic drift?

Answer 14

variation in genotypes in a small population because of the chance disappearance of particular genes
(because individuals die / do not reproduce)

Question 15

what is genetic bottleneck?

Answer 15

extreme example of genetic drift (when size of population is severely reduced)
-> population is decimated & on,he small, random assortment of survivors remain

Question 16

what 3 environmental factors will exert selection factors?

Answer 16

• availability of food
• abiotic
• biotic