Evolution Exam Question Answers VCAA, Exam 2,

Inability to mate is not enough evidence; it is the inability to produce viable offspring which is important.

Allopatric speciation There were different selection pressures in the two environments, which allowed differences in allele frequencies to develop. Over time there is an accumulation of genetic differences which changes a trait, such as mating behaviour.

The effect of the diet on the size of the jaw.

Island snakes’ (groups A and B) jaw length increased in size when large prey was eaten. Mainland snakes (groups C and D) had normal jaw length at maturity. The size of the prey given.

Students needed to make the following points in their responses: the island and mainland snakes were geographically isolated or no gene flow each population experienced different selection pressures populations, if reintroduced, were unable to produce viable fertile offspring.

Stratigraphy could be used, where the relative age of a fossil can be determined by the position of that stratum.

Convergent Evolution killed and ate fresh meat hunted Ambush rather than pursuit Grappled and killed prey Killed by biting (jugular, spine of prey) killing teeth slicing teeth no grinding teeth for crunching old bones Short strong limbs – suited for grappling, not running fast or climbing opposable thumbs for holding claws for killing or climbing long front teeth powerful jaws

Students needed to make both of the following points: DNA hybridisation involves the dissociation of different samples of DNA and their reassociation, providing a measure of similarity the greater the similarity of the DNA (determined by melting temperature), the more closely related the two organisms are from which the samples were taken.

Any one of: artefacts associated with the production of clothing, such as bone needles fossilised remains of clothing cave paintings showing humans wearing clothes. Living in clothing provided the lice with: a warm environment close contact to the whole body more places to hide an easier way to transfer between hosts.

Different palaeontologists may make different interpretations of the same data.

Either of: Australopithecus afarensis evolved about three million years ago Homo heidelbergensis evolved from Homo ergaster (about one million years ago). Any of: Homo erectus evolved from Australopithecus afarensis in Model 1 Homo erectus evolved from Homo ergaster in Model 2 Model 2 shows linear evolution from Australopithecus afarensis. Homo erectus had: a larger brain case/ a less prominent brow ridge/ a more parabolic jaw. Or Correct statements with respect to teeth size or position of foramen magnum received one mark for each correct feature named. Any of: different customs and lifestyle prevented interbreeding different mating behaviour or rituals mating occurred, however, viable offspring were not produced.

The bird was rapidly covered by sediment, and one of: hidden from scavengers decreased rate of decomposition undisturbed

Both of: stratigraphy is where layers of sediment build up over time the oldest fossils are found in the lowest stratum (or the converse).

Mountain range/dry ground/road/or any other suitable answer All of: the two separated populations have different gene pools/genetic variation/mutations present different selection pressures/environments/natural selection acts on each population if the two populations, when brought together, do not produce fertile offspring, they are different species

The change in allele frequency in a population by chance

Students were required to give two points: -Fewer alleles present in the Illinois population -Less variation present -Greater risk of extinction Either of: - Gene flow or intrebreeding has occurred between the two populations Both of: - An environmental condition such as a disease - Members of the population are more susceptible or at risk of extinction

One of: -Breed with other members of population from other states -Use a captive breeding program -Habitat protection/modification