module 4

Question 1

what is trophic ecology?

Answer 1

the study of feeding relationships between organisms.

Question 2

equation for efficiency in food webs

Answer 2

(Yt)^n

Yt - trophic yield (function of growth and metabolism)

n - number of trophic levels

Question 3

what does it mean when a food web is size structured

Answer 3

body size is related to the position of the organism in the food web.

Question 4

what are marine food webs dominated by?

why is this the case

Answer 4

small organisms

higher rates of reproduction, takes less time to grow, consume less than larger organisms.

Question 5

bait balls

Answer 5

gather schools of fish or plankton in one area and feed on it.

Question 6

ram-feeding

Answer 6

swimming through water column with mouth open

Question 7

lunge-feeding

Answer 7

swim with mouth open and filter it through.

Question 8

bubble-net feeding

Answer 8

Whales release bubbles through blowholes to trap schools of fish in one area.

Question 9

chemosynthesis

Answer 9

uses energy released by inorganic chemical reactions to make sugars.

common in places where primary producers cannot receive sunlight for photosynthesis.

Question 10

5 main chemosynthetic habitats in the oceans

Answer 10

1. contiental slope sediments

2.hydrothermal vents

3. whale and food falls
4. cold seeps
5. shallow-water sediments

Question 11

trophic cascades

Answer 11

non-linear ecological interaction whereby a change in upper (lower) trophic levels induces dramatic shifts in lower (upper) trophic levels.

Question 12

trophic cascade in otters and kelp

Answer 12

otter numbers decrease
(don’t feed on sea urchins)

sea urchins increase
(feed on kelp)

kelp decreases

Question 13

trophic compensation

Answer 13

change in upper trophic level does not propagate down the food web.

the potential for compensation depends on the potential for the individuals to respond to predation and on the trophic diversity and complexity of food webs.

Question 14

mesoconsumer release

Answer 14

when collapses in top predator populations are associated with dramatic increases in abundance of smaller predators.

Question 15

marine biodiversity

Answer 15

the variety of life in the oceans comprising ecological, organismal and genetic components.

Question 16

ecological diversity

Answer 16

the variety of biomes, ecosystems and habitats in the ocean.

Question 17

species diversity

Answer 17

alpha, beta and gamma, taxonomic diversity, shannon’s diversity, evenness across different species

Question 18

functional diversity

Answer 18

same metrics as species diversity but measured across different functional traits.

Question 19

genetic diversity

Answer 19

same metrics as species diversity but also phylogenetic differences, measured across populations, individuals and genes.

Question 20

where is there a higher diversity of reef fish species found?

Answer 20

in the tropics

Question 21

where is there higher functional diversity of fish?

Answer 21

Galapagos islands and on the south west coast of Africa

Question 22

biodiversity hotspots

Answer 22

regions or habitats with disproportionately high biodiversity value.

measured as the number of rare, endemic or endangered components

Question 22

coral triangle

Answer 22

example of a biodiversity hotspot.

• habitat diversity leads to increase in niches
• genera are young, either evolving here or surviving here while going extinct elsewhere
• minimal disturbance from sea level rise

Question 23

bathymetric gradient

why is this so?

Answer 23

depth gradient

higher species richness and diversity in shallow water.

• don’t have as much data about the deep sea as we do about shallower depths

Question 24

abyssal plains

Answer 24

flat muddy plains in the deep sea.

Question 25

deep-sea biodiversity hotspots

Answer 25

cold water coral reefs seamounts shipwrecks and other structures.

Question 26

what are the 7 reasons why diversity reduces with increasing latitude

Answer 26

1. time-stability hypothesis 2. rapports rule 3. Species-area hypothesis 4. Differences in geological history 5. Gradients in solar energy input/levels of productivity 6. Mid-domain effect 7. Differences in rates of evolutionary processes

Question 27

time stability hypothesis

Answer 27

tropics are more stable over evolutionary time than poles

Question 28

Rapoport’s rule

Answer 28

small geographic ranges in the tropics permit species co-existence, broader geographic ranges in higher latitudes result in lower diversity

Question 29

Species-area hypothesis

Answer 29

the tropics cover a larger area so can support more species

Question 30

Differences in geological history

Answer 30

higher latitudes are younger

Question 31

Gradients in solar energy input/levels of productivity

Answer 31

low latitudes more productive

Question 32

Mid-domain effect

Answer 32

denser species packing around geographic midpoints of distribution

Question 33

Differences in rates of evolutionary processes

Answer 33

speciation and extinction rates differ in the tropics and poles.

Question 34

why is there a higher biodiversity in the southern ocean?

Answer 34

1. older ocean - arctic is still being colonised by new species 2. larger area 3. higher structural heterogeneity (leads to higher number of species' niches)

Question 35

intermediate disturbance hypothesis

Answer 35

we always find highest biodiversity in areas with intermediate disturbances. Infrequent disturbance lets slower-growing but competitively superior species (k-selected species) dominate and exclude other species, while frequent disturbance favours only species that are fast-growing good colonisers (r-selected species).

Question 36

marine biogeography

Answer 36

explores how groupings (clusters) of species form geographically distinct ecosystems and causal mechanisms of these groupings.

Question 37

biogeographic realm

Answer 37

very large regions of coastal, benthic or pelagic ocean across which biotas are internally coherent at higher taxonomic levels due to shared and unique evolutionary history.

Question 38

biogeographic provinces

Answer 38

nested in realms large areas defined by the presence of distinct biotas that have at least some cohesion over evolutionary time frames.

Question 39

biogeographic ecoregion

Answer 39

smaller units. areas of relatively homogenous species composition, clearly distinct from adjacent systems.

Question 40

how many marine realms are there?

Answer 40

30

Question 41

which organisms contribute to differences in boundaries?

Answer 41

endemic species contribute most to the creation of boundaries because of lack of mobility, inputs of freshwater, continental drift, geographical/bathymetric ranges of the animals.

Question 42

what 6 environmental conditions contribute to creation of boundaries?

Answer 42

1. temperature 2. salinity 3. dissolved oxygen 4. nitrate 5. phosphate 6. silicate