Biodiversity

Question 1

Humboldt

Answer 1

Mapped out climatic zones using isothermal lines

Question 2

Latitudinal diversity gradient

Answer 2

Nearer to tropics, incr in no of species

More species and diversity at lower latitudes

Question 3

Latitude

Answer 3

Diversity peaks in equatorial regions, especially tropical rainforests, and decr in cooler areas (as well as deserts)
Towards poles fewer species
Holds for marine ecosystems

Question 4

Altitudinal gradient

Answer 4

As distance from sea level increases, diversity decr

Question 5

Depth gradient

Answer 5

As one descends into the ocean, fewer species

Question 6

Area effects

Answer 6

strong positive relationship between size of island and number of species
Larger areas support more species

Question 7

alpha diversity

Answer 7

species richness

total species for a limited area

Question 8

eveness

Answer 8

relative abundance of species in a habitat

Question 9

beta diversity (turnover)

Answer 9

difference of a habitat from other habitats

endemicity

Question 10

Gamma diversity

Answer 10

sum of everything in a region

regional diversity

Question 11

functional diversity

Answer 11

what those species do

Question 12

In a more diverse assemblage..

Answer 12

abundance doesn’t drop off as quickly (for different species)
Rare things are less rare
Fauna is more even

Question 13

Simpson’s index

Answer 13

lower index means higher diversity- useful to take an inverse
calculates eveness

Question 14

Beta diversity is inversely proportional to

Answer 14

shared species: high beta means few shared species

Question 15

Beta diversity goes up with

Answer 15

distance

Question 16

Jaccard similarity index

Answer 16

calculates beta diversity
measure of overlap
1- both habitats have same species
0- no species in common

Question 17

Tropical overlap

Answer 17

overlap between different tropical habitats low

have restricted distributions

Question 18

Latitudinal gradient in beta diversity

Answer 18

similarity decr with incr distance

but it does much faster at low latitudes

Question 19

HIgh tropical diversity is a function of

Answer 19

high alpha and beta diversity

Question 20

species-area curve:

Answer 20

alpha- along the left, local
Gamma: regional, on the right
Beta: links the two, determines the slope- if beta diversity high, curve will incr rapidly as you sample new habitats
See diagram

Question 21

high functional diversity

Answer 21

diversity in size, ecology (carnivore,herbivore), locomotion (running, walking, climbing)

Question 22

explanations for diversity patterns

Answer 22

habitat heterogeneity
environmental disturbance
species-area effects
primary productivity
temp

Question 23

Habitat heterogeneity

Answer 23

different habitats support different species
More habitats = more species
Maybe tropics more diverse because more heterogeneity?
- BUt never been shows that the tropics are more diverse in habitats

Question 24

Intermediate disturbance hypothesis

Answer 24

too much disturbance prevents species becoming established
Too little means a few species are able to crowd everybody else out
A goldilocks level of disturbance is low enough to let many species get established, but high enough that dominants get killed off freq- can’t take over

Question 25

Problem with intermediate disturbance hypothesis

Answer 25

no evidence that disturbance levels are that different in tropical rainforest than in other habitats

Question 26

Historical effects

Answer 26

Are the tropics more stable?
Predicted effects of climate change worse at higher latitudes
WArming/cooling more severe at high latitudes

Question 27

Species-area effects

Answer 27

explains to some extent why so many species in the tropics- large area

Question 28

Problem with species- area

Answer 28

Asia largest land mass- temperate

If species diversity were just driven by area, Russia and Siberia would have more species

Question 29

Mid domain effects

Answer 29

argues if you have a bunch of species with varying latitudinal ranges and randomly arrange them, the widely distributed species will include the tropics
Wide ranging things overlap in the middle

Question 30

Problem with mid domain effects

Answer 30

assumes tropics have lots of things with large geographic ranges but tropics have lots of things with v small ranges (high beta diversity)

Question 31

Primary productivity

Answer 31

Relationship between PP and diversity complicated
Low productivity ecosystem have few species, but some high productivity environments have lots of species, and some don’t
Diversity incr with PP up to a point, then levels out/decreases

Question 32

PP measured in terms of

Answer 32

evapotranspiration etcc

Question 33

Temp

Answer 33

strong positive correlation between temp (SST) and diversity

Question 34

Bacterial diversity

Answer 34

diversity, measured by sequencing dna, shows a correlation between latitude and temp, but weak with PP or abundance

Question 35

Evolutionary dynamics

Answer 35

Tropics have high BRS/ diversification, and low extinction

Question 36

Dispersal dynamics

Answer 36

many groups originate at low latitudes, then spread to high latitudes

Question 37

Conclusions

Answer 37

species-area effects, mid-domain effects, habitat heterogeneity and disturbance effect diversity, but not enough to explain diversity gradient
Productivity and temp main drivers of latitudinal diversity gradients, but why is poorly understood
Not only is diversity diff in tropics, evol dynamics is too- high speciation and low extinction

Question 38

isothermal line

Answer 38

a line on a weather map or chart connecting points having equal temperature.