PCE - 11

Question 1

what are examples of macroecology?

Answer 1

SARs, islands biogeography and latitudinal gradients

Question 2

what are the goals of macroecology?

Answer 2

• To identify general emergent patterns in ecological systems
• General processes/mechanisms reflected in ‘emergent’
  patterns in statistical distributions of individuals, populations and species
• To test for repeatability of patterns in statistical distributions to infer the presence of ‘law-like’ ecological processes

Question 3

what were Alexander von humboldts observations of varying latitudes and what did he hypothesise?

Answer 3

many more species at low latitudes and he hypohtesised that temperature was the cause

Question 4

how can you map global richness?

Answer 4

by dividing the world into equal areas and measure richness

Question 5

what are the 2 main categories of hypotheses for ‘what determines variation in the number of species in a community at a global scale?’

Answer 5

1) climatic/ environmental factors (ecology)

2) historical factors (evolution)

Question 6

what 2 things can climatic factors affect?

Answer 6

1) energy / productivity of an area

2) spatial and habitat heterogenity (diversity)

Question 7

what is PET?

Answer 7

potential evapotranspiration - amount of water that would evaporate or be transpired from a saturated surface - primitive measure of available energy or productivity

Question 8

describe energy/ productivity patterns?

Answer 8

as energy increases = faster growth rates and larger populations, narrower ranged species can co-exsist

Question 9

what does habitat heterogeneity reflect?

Answer 9

• a resource axis and the extent of potential niches

- allows for more species with small niches to co-occur

Question 10

what are the 2 things that can determine the number of species that can co-exist

Answer 10

1) climate

2) environment

Question 11

how do you work out net diversification?

Answer 11

speciation rate - extinction rate

Question 12

describe the tropical cradles model

Answer 12

• the tropics are home to young, rapidly speciating lineages
• speciation rate peaks in the tropics
• extinction rate invariant with latitude

Question 13

describe the tropical museums model

Answer 13

• home to old relictual species
• speciation rate invariant
• extinction rate declines in the tropics

Question 14

what are the 3 historical processes (evolution)?

Answer 14

1) tropical cradles of diversity
2) tropical museums of diversity
3) out of the tropics

Question 15

describe the out of the tropics model?

Answer 15

• species form in the tropics and move to extratropics
• speciation rate peaks in the tropics
• extinction rate declines in the tropics

Question 16

what are ecogeographical rules?

Answer 16

variation in the traits of organisms over geographical or environmental gradients

Question 17

what were bergmanns rule hypotheses?

Answer 17

he proposed that large body size is advantageous at high latitudes due to it reducing heat loss from a lower surface area to volume ratio

Question 18

after many tests what were the conclusions of bergmanns rule?

Answer 18

a common pattern driven by multiple processes:

• thermoregulation (intra and interspecific)
• taxonomic turnover (interspecific) - how many taxa are alive at the time
• community assembly (interspecific) - the identity and abundance of species within a community

Question 19

what did Allen observe?

Answer 19

he observed that the length of appendages in closely related endothermic vertebrates increased in hotter environments

Question 20

what was Allens hypothesis?

Answer 20

thermoregulation - shorter appendages conserve heat and longer appendages are more effective in dissipating heat

Question 21

what were the conclusions to allens rule on pattern?

Answer 21

• strong support for his rule

- data support both pattern and process

Question 22

why are marine ecogeographical rules less well studied?

Answer 22

because marine data is harder to collect

Question 23

what is jordans marine ecogeographical rule?

Answer 23

• number of vertebrae in marine fish increases towards higher latitude
• may be related to body size trend
• weak in migrant fish, stronger pattern in non-migrant species

Question 24

what is Thorsons marine ecogeographical rule?

Answer 24

Dominant mode of development switches from
pelagic (larvae disperse with ocean current) in the tropics to direct development (no dispersal) at higher latitudes– direct developers more likely to become geographically isolated and speciate at high latitudes

Question 25

what is Glogers ecogeographical rule?

Answer 25

pigmentation is darker in hot and humid zones (observation from birds)- few tests little support

Question 26

with is rapoports rule?

Answer 26

the tendency for species ranges to become smaller at lower (tropical) latitudes- many tests, equivocal (questionable) support

Question 27

what is the problem with Bergmans rule on latitude?

Answer 27

there is too much focus on latitude causing the differences in body size when actually the pattern is really about temperature

Question 28

what were the conclusions to bergmanns rule after testing wether temperature had an effect on interspecific species?

Answer 28

temperature is the strongest predictor of body size within genera, families and order but not the only part of the picture

Question 29

what genera have the widest overall temp range?

Answer 29

orders/families that occur at low temps

Question 30

describe energy/ productivity patterns?

Answer 30

they are inconsistent - can show that productivity effects species richness but in some taxas it doesnt