Unit 5 Lecture 29

Question 1

What does biodiversity mean?

Answer 1

Pattern that has been observed where there are more species in the tropics at the center of land masses than there are at the poles

Question 2

Explain the first hypothesis for why biodiversity hotspots are in the tropics:
- More productivity

Answer 2

Tropics is warmer and has more water allowing for more resources and lower competition
- more primary producers = more trophic levels can be supported (bottom-up control)

Question 3

What species of marine is significantly correlated with mean surface water temp?

Answer 3

gastropods

Question 4

What is the energy-diversity hypothesis

Answer 4

Energy output is most strongly correlated with species richness in the Northern hemisphere
Precipitation is most strongly correlated with species richness throughout the tropics and into the Southern Hemisphere

Species richness increases with PET (amount of water that a plant would lost to the environment) up to a certain threshold then levels off

Question 5

Explain the first hypothesis for why biodiversity hotspots are in the tropics:
- More consistent environment

Answer 5

• increased speciation in the tropics and the tropics has a high production of species in the tropics

Question 6

Diversity is a function of what?

Answer 6

Speciation rate, extinction rate, and immigration rate

Question 7

What are the parameters for the tropics to be a cradle? museum?

Answer 7

Cradle: produce diversity (more species and a higher origination rate)

Museum: maintain diversity (aren’t making species fast but just losing species slowly)

Question 8

What does the OTT model mean?

Answer 8

Out of the tropics model: argued everything was better in the tropics; higher origination rate, lower extinction rates, lower immigration rate (more species produced, fewer species going extinct), more species in the tropics to immigrate into extra tropics

Question 9

Are the tropics a cradle? museum? or both?

Answer 9

Tropics produce more species and have a lower extinction rate (OTT Model)

Question 10

Explain the first hypothesis for why biodiversity hotspots are in the tropics:
- More complex habitat

Answer 10

• More opportunity for niche partitioning

Question 11

Explain the first hypothesis for why biodiversity hotspots are in the tropics:
- Geometric contraints

Answer 11

Larger range in center of domain (tropics)
- Idea that diversity is maximized in the center of a bounded domain simply because more ranges pile up in the middle

Question 12

Explain the first hypothesis for why biodiversity hotspots are in the tropics:
- More land area

Answer 12

Land area in tropics is biggest

Question 13

What are the 3 causes of biodiversity?

Answer 13

A. Dispersal or immigration: amount of area+distance from other areas
B. Abiotic factors (climate, disturbance)
C. Species interaction (competition, predation, herbivory, parasitism)

Question 14

Why are pronghorns fast?

Answer 14

Because they developed in the presence of cheetahs (this was co-evolution

Question 15

What are fossils? chemical fossils;s? trace fossils?

Answer 15

fossils: preserved remains or traces of animals, plants, or organisms

chemical fossils: chemical signatures found in fossils that indicate different kinds of life

Trace fossils: evidence of past behavior

Question 16

What are some potential downfalls to fossils?

Answer 16

• experimental approaches and direct measurement of environmental parameters difficult
• Distortion and loss of information often = coarse resolution

Question 17

Positive/negative relationship between temperature and richness

Answer 17

positive

Question 18

Explain the 3 evolutionary faunas

Answer 18

1. Cambrian: low diversity, food webs simple
2. Paleozoic: diversity increased, food webs more intriquite
3. Modern: diversity high, high food web