3.2 Origins of Biodiversity

Question 1

Wallace Line

Answer 1

Named for Alfred Wallace. To the west of the Wallace Line, the islands are characterized by fauna and flora that are predominantly Asian in origin. To the east, the islands host a mixture of Australian-origin species like marsupials.

Question 2

Landbridge

Answer 2

Areas which at times have been above sea level and navigable by terrestrial fauna.

Question 3

Endemic/Endemism

Answer 3

Occurring nowhere else on Earth.
The % endemism of a place is the proportion of unique species.

Question 4

Placental

Answer 4

A class of mammal which give birth to live young (which develop inside the womb and are nourished through a placenta). From an evolutionary standpoint, placentals babies are subject to fewer environmental pressures than marsupials.

Question 5

Galapagos Finches

Answer 5

The text-book example of adaptive radiation. They evolved different beak shapes and sizes to best match the food resources available on their islands.

Question 6

Galapagos Islands

Answer 6

A volcanic archipelago in the Pacific Ocean. Often studied for its contribution to evolutionary theory.

Question 7

Madagascar

Answer 7

An African island on which lemurs undertook evolution to adapt to take advantage of a variety of trophic and habitat niches.

Question 8

Trophic niche

Answer 8

Where an organism fits in the food chain. Relates to what they eat and what eats them.

Question 9

Habitat niche

Answer 9

Where an organism lives. For example, can be arboreal (in the trees), or terrestrial (on the ground)

Question 10

Terrestrial

Answer 10

on the ground

Question 11

Arboreal

Answer 11

in the trees

Question 12

Niche

Answer 12

refers to the role or function of an organism or species within an ecosystem, encompassing its relationships with other living organisms and its interactions with the physical environment.

Question 13

Survival of the fittest

Answer 13

A concept associated with evolutionary biology in which only those organisms best adapted to their environments successfully procreate and pass their genes to successive generations.

Question 14

Natural Selection

Answer 14

The concept associated with evolutionary biology which explains how traits become more or less common in a population over time based on the reproductive success of organisms with those traits.
More correct to use than “survival of the fittest”

Question 15

Evolution

Answer 15

How an organism changes over successive generations to adapt to available resources and conditions.

Can occur through mutations or natural selection.

Question 16

Darwin’s famous book

Answer 16

“On the Origin of Speices” (1859)

Question 17

Why are many of New Zealand’s birds flightless?

Answer 17

They evolved in the absence of other mammals or reptiles to occupy available niches, including terrestrial ones, and were successful owing to the absence of predators.

Question 18

Geographic Isolation

Answer 18

A barrier (natural or manmade) which prevents genetic flow between populations and can lead to speciation (development of separate species).

Question 19

Speciation

Answer 19

The evolution of populations of the same species separated by a physical barrier into two different species that cannot successfully interbreed.

Question 20

Pangea

Answer 20

The supercontinent. Split into Gondwanaland (South America, Africa, Australia and Antarctica) and Laurasia (North America, Europe and Asia) 175 million years ago.

Question 21

Gondwanaland

Answer 21

Supercontinent comprising of South America, Africa, Australia, Antarctica and India (separated from Pangea 175 million years ago)

Question 22

Laurasia

Answer 22

Supercontinent comprising of North America, Europe and Asia (separated from Pangea 175 million years ago)

Question 23

Continental Drift

Answer 23

The idea that continental and oceanic plates (as part of the Earth’s crust) are drifting around atop the mantle. Similar to plate tectonics (which describes the mechanism for this drifting).

Question 24

Temporal Isolation

Answer 24

When two organisms or populations are separated due to the time of day they are active. Similar to behavioral isolation.

Question 25

Inheritance

Answer 25

The passing down of genetic material from one generation to the next.

Question 26

Extinction

Answer 26

Death of the last individual of a species.

Question 27

Endangered

Answer 27

A reduction of between 50-70% of a population size within 10 years, or three generations.

Question 28

Anthropocene Extinction

Answer 28

the ongoing mass extinction primarily due to human activity affecting the planet’s climate and ecosystems.
The “sixth extinction”.

Question 29

Mass extinction

Answer 29

Rapid and widespread extinction event. 70-96% loss of biodiversity.
There have been five of them in the last 500 million years. We are probably in the midst of a sixth.

Question 30

Causes of mass extinction events

Answer 30

1. Short, severe ice age
2. Widespread ocean anoxia
3. Massive volcanic eruptions
4. Ocean acidification
5. Asteroid impact

Question 31

Factors that can make a species less prone to extinction

Answer 31

• Genetic diversity (resilience)
• Wide geographic range
• High reproductive rate
• Ecological plasticity and flexibility

Question 32

Background extinction rate

Answer 32

The natural, steady rate of species extinctions occurring as part of Earth’s evolutionary process. Varies between taxa. Measured as # of species/time.