3.7.3 Evolution May Lead To Speciation

Question 1

What factors cause individuals in a population to show variation in phenotype

Answer 1

Genetic and environmental factors

Question 2

What causes genetic variation

Answer 2

Mutations, main source of variation, sudden change in genes, may or may not be passed on

Meiosis, produced new combinations of alleles before they pass into gametes, all are different

Random fertilisation of gametes, any gamete from one parent can fuse with any gamete from the other parent, new combinations of alleles, adds to variety of offspring

Sexual reproduction uses all 3 methods

Question 3

What are environmental factors

Answer 3

Climate conditions like rainfall sunlight and temp
Soil conditions
pH
Food availability

Variation is mainly due to a combination of genetic differences and environmental influences

Question 4

What are selection pressures give examples

Answer 4

Environmental factors which limit the population of a species

Predation
Disease
Competition

Question 5

Process of the evolution by natural selection

Answer 5

Species have high death rates due to predation, competition and disease, so increased their reproductive rate to produce the next generation.
Too many offspring lead to infraspecific competition
Organisms best suited to the environmental conditions are more likely to survive, more likely to breed, pass on favourable alleles to next generation
New generation have a different allele frequency from previous generation