BIOSCI 395 (08/11/2022 17:00) Pacific Biogeography and Biodiversity (Exam)

Answer EITHER a OR b for each of the four questions.

Question 1

Either:

How did the concept of “Centres of Origin” evolve as the field of biogeography has advanced? Include the pre-Darwinian and post-Darwinian period. Explain the main factors causing these changes.

Or:

Can we test hypotheses of long-distance dispersal (LDD), or are these hypotheses untestable because they invoke large amount of luck/chance? Explain your answer.

(25 marks)

Question 2

Either:

Describe the Flora of New Caledonia and its very high diversity relative to other land masses. You should include mention of the ancient vicariant element of plants on this island. You should also outline with examples the key role that the ultramafic surface has played as a center of plant evolution and diversity. Mention also the different types of plant community on the island and their different levels of diversity, endemism and their divergent sources from other land masses. Attempt an explanation as to why New Caledonia has much higher plant diversity than adjacent islands.

Or:

Describe the island of New Guinea in terms of its great species diversity and biogeographic relationships. Begin by outlining the altitudinal zonation of its forests from tropical lowlands to cool montane conditions. Then describe with examples the biogeographic relationships of New Guinea both in terms of its source status for the rest of tropical Oceania and of its relationship to adjacent Australia.

(25 marks)

Question 3

Either:

Australia was the first of the major landmasses to suffer extinction of its Megafauna in the late Pleistocene and it has also suffered the greatest extinctions. Discuss this event in terms of the two competing hypotheses – human hunting and climate change – that might explain it and refer to the key arguments used by the proponents of each hypothesis.

Or:

The Bassian Province of Australia is split between the south-western and south-eastern corners of the continent where somewhat cooler and wetter conditions occur. In the south-west there are a number of biogeographic patterns of speciation that include: vicariance (relative to the southeast); ancient Gondwanan remnant species (relative to the other Gondwanan landmasses); niche shifts from mesic (moist) to xeric (dry) habitat adaptation; and radiations of species that are solely confined to the small moist corner of the south-west of the continent. Describe these patterns with examples from the lecture.

(25 marks)

Question 4

Either:

Explain the difference between “taxon counting” approaches to studying large-scale biogeographical patterns (e.g., the latitudinal diversity gradient, LDG), versus phylogenetic approaches. How might phylogenies allow us to better test hypotheses for explaining a large-scale biogeographic pattern?

Or:

How can Akaike Information Criterion (AIC) be used to statistically compare multiple working hypotheses/models for some biogeographical dataset? In your explanation be sure to address the rationale for AIC (conceptually, no math), and whether or not AIC-based model comparisons aim to identify the true model.

(25 marks)