Lecture 4

Question 1

What is species richness (S)?

Answer 1

the number of species found in a (particular) community

Question 2

What is species evenness (E)?

Answer 2

the relative abundance of the different species making up the richness of an area

Question 3

Shannon diversity index

Answer 3

an example of a diversity indices that has been created to account for differences in species richness and evenness

Question 4

Alpha diversity

Answer 4

the number of species in a given community

Question 5

Gamma diversity

Answer 5

the number of species in a large region or continent

Question 6

Beta diversity

Answer 6

the rate of change of species composition along an environmental or geographical gradient
- links alpha and gamma diversity

Question 7

Mass extinctions

Answer 7

suggest that numerous species can go extinct during short time period

Question 8

background extinction rate

Answer 8

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Question 9

A species trait that are also associated with increased extinction rate

Answer 9

Body size - within a given lineage, larger-bodied are more at risk

Question 10

Specialist species

Answer 10

those with a narrow range of food or habitats

Question 11

Endemic species

Answer 11

those with a distribution limited to one, often small defined area

Question 12

Functional extinction

Answer 12

occurs when the abundance of a formerly ecologically important species becomes so drastically reduced that the species no longer plays a major role in the ecosystem
- so few of the species in an area that they are not impacting the environment around them

Question 13

What is an example of a functional extinction?

Answer 13

Green Sea Turtles

• once numbered tens of millions in the Caribbean, not only ~1 million
• used to keep seagrass beds short so they didn’t accumulate sediment
• seagrass beds have now collapsed

Question 14

Difference between extinct, extinct in the wild, and functionally extinct

Answer 14

• extinct - gone from the face of the earth
• extinct in the wild - means that they are gone from the wild but still alive in captivity
• functionally extinct (short version) - so few of the species in an area that they are not impacting the environment around them

Question 15

Inbreeding depression

Answer 15

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• a like organism mating with a like organism, like mating with relatives
• i.e. small, isolated populations of European Vipers suffer from low reproductive and survival rates