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Biology 413 (Zoogeography) Final Exam – Practice Questions
Winter Term 2
Directions:
1. Write your name and student number on each page of the exam.
2. All answers should be written in the space provided. If you need extra space, you can use
extra paper, but clearly label your answers.
3. The exam is designed to be completed in 2.5 hours.
4. The exam questions are organized into two parts and consist of six pages.
5. PART I consists of 10 short-answer questions.
6. PART II consists of two long-answer (essay-form) questions and one multi-part question.
Points
PART I: 30 points
PART II: 45 points
TOTAL: 75 points
PART I
Answer the following 10 questions using 2-3 sentences or less. These questions should take you less
than 5 minutes each. Please use the space provided. Each question in this section is worth 3 points.
Question 1: What is the Island Rule in island biogeography? Give two potential causes of the Island
Rule, one that pertains to large-bodied organisms and one that pertains to small-bodied organisms.
The Island Rule is the observed trend in island-inhabiting vertebrates from gigantism of species with
small mainland ancestors (e.g., mice and voles) to dwarfism of species with large mainland ancestors
(e.g., canids, ungulates, and elephants). Possible explanations/causes of the pattern include ecological
release from larger predators/competitors (in the case of gigantism) or from smaller species in the case
of dwarfism. Resource limitation may also lead to dwarfism in large-bodied species with large mainland
ancestors.
Question 2: What are the three dominant cycles that together make up the Milankovitch cycles? In
general, what do these cycles impact to influence the Earth’s climate system and the advance and retreat
of glaciers?
Eccentricity (or ellipticity of orbit); Axial tilt (obliquity); Precession (pole wandering). The cycles
generally impact the seasonality and location of solar energy around the Earth, thereby influencing
Earth’s climate cycles and the advance and retreat of glaciers
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Question 3: Provide one line of evidence indicating that Beringia was an important glacial refugium.
A refugium is a location that remained relatively unchanged during cycles of glaciation, and thus served
as refuge for species displace by glacial advance. Several lines of evidence suggest that Beringia was
likely an important glacial refugium. (1) It is a current center of endemism for many plant species, so it
was likely isolated, potentially repeatedly, such that some species were able to persist in this region over
time. (2) Several species or phylogroups have clades associated with Beringia, likely following
expansion after glacial retreat (e.g., collared lemmings). (3) There is also fossil evidence (for collared
lemmings) occurring in Beringia during the late Pleistocene.
Question 4: Endemic species can be classified by their location of origin. What is the difference between
autoendemics and alloendemics?
Autoendemics evolved in an area within their current distribution. Alloendemics (also known as relicts)
originated somewhere else, dispersed to their current locality and have subsequently gone extinct in
other parts of the former range.
Question 5: What are three potential causes of disjunction of populations and or related species groups?
Vicariance, extinction, long-distance dispersal______________________________________________
___________________________________________________________________________________
Question 6: In the space provided, answer the following questions regarding coalescence (i.e., in a gene
tree, the point in time at which two allelic lineages diverged from an ancestral lineage).
a. Would the time to the first coalescence in a population with 8 alleles be longer or shorter than the
time to first coalescence in an equivalent population with 4 alleles? _longer___________________
b. Would the time to complete coalescence in a large population be longer or shorter than the time to
complete coalescence in a small population? _longer_____________________________________
c. Similarity of genetic sequences is often used to reconstruct the phylogenetic relationships among
species. In many cases, the divergence of a gene reflects the recognized history of divergence
among species (i.e., a gene tree reflects the species tree). In some cases, however, genetic
divergence or dissimilarity does not reflect the species history (i.e., a gene tree does not reflect the
species tree). What is the name of this phenomenon? _Incomplete lineage sorting_______________
Question 7: List the three ways that a species or population can respond when climate change causes its
climate envelope to shift to higher latitudes or to higher elevations.
___________________________________________________________________________________
Extinction, Emigration (via distributional shift), Evolution (via adaptation)
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PART II Answer the following questions using the space provided, with complete sentences as
necessary. Each question in this section is worth 15 points.
Question 8: Answer the following questions regarding the Equilibrium Theory of Island Biogeography.
[15 points total]
Number of species
a) In the space below, draw the expected relationship between the number of species (S) on the y-axis
and area (A) on the x-axis, where the axes are not logarithmic (log) scale. [3 points]
Island (b) – 200 km from mainland
Island (a) – 1000 km from mainland
Area
b) Consider that the figure you drew in part (a) above represents an island archipelago composed of
islands of different sizes that sit approximately 1000 km from the continental source of fauna. In the
figure above, add a new line to represent the species-area relationship for an equivalent archipelago
of islands located only 200 km from the continental source of fauna (clearly label the lines in your
figure). [2 points]. Explain the reasoning for where you drew your new line. [3 points]
The number of species increases with area to an asymptote at maximum species capacity. ETIB predicts
that immigration rates will be on the whole lower for islands that are farther from a continental or
mainland source, therefore the number of species should be lower for island archipelago (A), which is
800 km farther from the mainland than island archipelago (B). Another acceptable prediction would be
that given sufficient time, two island archipelagos with the same area would eventually reach similar
levels of species richness at equilibrium, but island archipelago (B) would reach this equilibrium more
quickly than (A).
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c) On the figure below, the lines provided show extinction and immigration curves for island “A”.
Label which curve represents extinction (EX) and which curve represents immigration (IM). On the
same figure, draw additional immigration and extinction curves for a different island (island “B”)
that is more isolated and smaller than island “A”. Label your graph clearly. [5 points]
IM
EX
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d) Which island (island “A” or island “B”) in your figure for part (c) has higher equilibrium species
richness (S)? Which island has higher equilibrium species turnover (T)? [2 points]
Island A has higher equilibrium species richness. Island B has higher equilibrium species turnover.
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