18. 3 Natural selection

Question 1

define gene pool

Answer 1

total number of alleles of all genes of all individuals within a particular population at a given time

Question 2

define selection pressure

Answer 2

the environmental factors that limit the population of a species

Question 3

what does natural selection depend upon

Answer 3

organisms produce more offspring than can be supported by available resources.
genetic variety within the populations of all species.
a variety of phenotypes that selection operates against .

Question 4

role of over-production of offspring in natural selection

Answer 4

too many offspring for available resources.
competition amongst individuals (intraspecific) for limited resources.
individuals of population best suited to conditions survive.
more likely to breed and pass on advantageous alleles to next generation.

Question 5

role of variation in natural selection

Answer 5

larger and more genetically varied population
greater chance that 1 or more of the individuals have combination of alleles that are advantageous in the struggle for survival.
more likely to breed and pass on advantageous alleles to next generation.

Question 6

4 factors that lead to differential survival and reproduction

Answer 6

predation
competition for resources e.g. food and water
disease
natural disaster