investigating selection

Question 1

what do different types of natural selection lead to

Answer 1

different frequency patterns

Question 2

what is an example of directional selection

Answer 2

antibiotic resistance

Question 3

what is directional resistance

Answer 3

directional selection is where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce. This could be in response to an environmental. Bacteria evolving antibiotic resistance is an example of directional selection.

Question 4

how does directional selection actually work step by step in the context of antibiotic resistance

Answer 4

1. some individuals ins a population have alleles that give them resistance to an antibiotic
2. the population is exposed to the antibiotic, killing bacteria without the resistant allele
3. the resistant bacteria survive and reproduce without competition, passing on the allele that gives antibiotic resistance to their offspring
4. after some time most organisms in the population will carry the antibiotic resistant allele

Question 5

what is human birth weight an example of

Answer 5

stabilising selection

Question 6

what is stabilising selection

Answer 6

stabilising is where individuals with alleles for characteristics towards the middle of the range are more likely to survive and reproduce.

Question 7

when does stabilising selection occur

Answer 7

it occurs when the environment isn’t changing, and it reduces the range of possible characteristics. An example of stabilising selection is human birth weight.

Question 8

what is a commonly used example of stabilising direction

Answer 8

the range of birth weights as a baby

as very small babies are less likely to survive partly because they find it hard to maintain their body temperature

giving birth to large baba is difficult so large babies gotta try and firm it too

so mid babies are favoured