Quick questions on Natural selection, fitness and the modern synthesis (QCE Biology Unit 4)

Natural selection acts whenever all four of the following are true.

Before industrial revolution: pale moths (peppered) camouflaged on lichen-covered tree bark; dark (melanic) form rare. As soot killed lichens and darkened bark, pale moths became visible to bird predators. By 1900, dark form was over 95 per cent in industrial areas.

Mutations conferring resistance occur spontaneously at low frequency. Antibiotic application kills sensitive cells. Resistant survivors reproduce and pass the resistance alleles on.

Released in 1935 to control sugarcane pests, they have expanded across northern Australia. The invasion front is moving faster than the rear, because the toads with the longest legs disperse fastest, reach new ground first, and have higher reproductive success there. Leg length at the invasion front has increased by about a third in 70 years.

Beak depth in Geospiza fortis tracks rainfall. In dry years only large hard seeds remain; large-beaked birds survive and breed. In wet years small soft seeds dominate and beak depth declines.

Fisher, Haldane, Wright, Mayr, Dobzhansky, Simpson and others integrated:

State the four conditions required for natural selection and explain the role of variation. [3 marks]

A peppered-moth-equivalent in a Brisbane industrial suburb: dark-form frequency rises from 5 to 80 percent over 50 generations. Calculate the change in allele frequency assuming Hardy-Weinberg and identify the selective pressure. [3 marks]

Compare Darwinian and neo-Darwinian theories of evolution. (a) Identify one key idea Darwin proposed. (b) Identify two additions in neo-Darwinism.