Lecture 21- Northern Ecological Concepts

Question 1

What is the latitudinal diversity gradient?

Answer 1

Species diversity declines with increasing distance from the equator

Question 2

Species accumulate ____ as you move towards the equator

Answer 2

Accumulate faster than expected

Question 3

____ climates support more species per number of individuals sampled

Answer 3

Warmer

Question 4

What is sympatric speciation?

Answer 4

• Arises within populations that continue to occupy same regions
• Arises as a result of random genetic mutations

Question 5

Sympatric speciation allows for?

Answer 5

Allows for niche partitioning

Question 6

What is allopatric speciation?

Answer 6

• Arises when 2 populations are geographically seperated
• Genetics and occupied niche change over time

Question 7

What are some limitations to species diversity?

Answer 7

• Niche theories
• Equilibrium theories
• Stabilizing mechanism
• Equalizing mechanism

Question 8

What is niche theory?

Answer 8

Competition for resources drives limits to new species establishing

Question 9

What is equilibrium theory?

Answer 9

Populations exist in equilibrium in a saturated environments

Question 10

What is a stabilizing mechanism?

Answer 10

Reduce competition between species to encourage higher diversity (ie. resource partitioning)

Question 11

What is equalizing mechanism?

Answer 11

Reduces competitive advantage of some species

Question 12

What are the three broad theories to cause diversity decline?

Answer 12

1. Productivity = Solar radiation, rainfall in relation to temperature, resource availability
2. Interactions = self-reinforcing effect of diversity
3. Stability = lack of glaciation

Question 13

Rainfall affects potential ______

Answer 13

Evapotranspiration (PET)

Question 14

How does rainfall affect the potential evapotranspiration?

Answer 14

• Amount of water that could be evaporated from the soil and transpired by plants
• Takes into account local average temperature and humidiy
• Good indicator of drought

Question 15

What causes changes in diversity?

Answer 15

• Solar radiation
• Rainfall
• Resource Availability
• Self-reinforcing effect of diversity
• Glaciation

Question 16

Once more species of plants live together, more species _______

Answer 16

More species of herbivores with evolve

Question 17

Greater diversity of herbivores may result in more ______

Answer 17

Species of predators

Question 18

Competition increases ______

Answer 18

Niche partitioning

Question 19

Rate new species evolve is slow in polar areas so never manage to _____

Answer 19

Recover to maximum number species

Question 20

What are the effects of climate instability?

Answer 20

Question 21

Why do different regions vary in number of species and type of species they contain?

Answer 21

• No single mechanims explains all patterns
• Likely different mechanisms between different taxa (plant energy driven, mammals area-dependent)

Question 22

What is rapoports rule?

Answer 22

• Geographic ranges of species are larger at high latitudes
• Explanation for higher diversity near equator
• Small ranges = more species in same are
• Large species ranges = no room for new species

Question 23

What are some limitations to species ranges?

Answer 23

• Dispersal
• Biotic
• Abiotic

Question 24

What is niche conservatism?

Answer 24

• Refers to climate niche
• Range of temperatures and precipitation a species can tolerate
• Moderates where species occur and how they adapt
• Species retain fundamental niche over time
• Species does not adapt to local changes in environment

Question 25

Niche conservatism more likely to result in _______

Answer 25

Allopatric speciation

Question 26

What are some limits to range expansion?

Answer 26

• Limited in north by cold temperatures
• Limited in south by competition
• Topographic barriers to dispersal