Food webs

Question 1

Autotrophs

Answer 1

Organisms that get energy from non-living environment to produce organic matter

Question 2

Photoautotrophs

Answer 2

Use solar energy

Question 3

Chemoautotrophs

Answer 3

Use energy from chemical compounds

Question 4

Heterotrophs

Answer 4

Feed on organic matter produced by autotrophs

Question 5

Primary producers

Answer 5

Autotrophs

Question 6

Consumers

Answer 6

heterotrophs

Question 7

Food chain

Answer 7

transfer of energy among primary producers and consumers

Question 8

Trophic level

Answer 8

each level in the foos chain

Question 9

Food webs

Answer 9

Complex trophic structures that include several primary producers, consumers that eat more than one kind of food, changes in diet with development

Question 10

How much energy is transferred to one level to the other in the trophic pyramid?

Answer 10

10%

Question 11

What is DOM?

Answer 11

Dissolved Organic Matter: waste organic matter dissolved in water

Question 12

What is the function of decomposers?

Answer 12

Decompose DOM or detritus to reintroduce it into the food web

Question 13

Nutrient regeneration

Answer 13

Reintroduction of DOM in food web

Question 14

What is the succession of species in microbial loop?

Answer 14

Phytoplankton, DOM, bacteria, protozoans, zooplankton

Question 15

What is detritus?

Answer 15

Non-living organic matter in solid form (dead organisms, etc.)

Question 16

What are detritivores?

Answer 16

Organisms that feed on DOM or detritus

Question 17

What are types of food webs?

Answer 17

Connectedness web
Energy flow web
Functional web

Question 18

Connectedness web

Answer 18

Shows feeding relationships among organisms

Question 19

Energy flow web

Answer 19

Connections quantified as energy fluxes

Question 20

Functional web

Answer 20

Describes influence of a population on the growth of another population

Question 21

Describe estuarine foodweb

Answer 21

Detritus-based, few herbivores, birds are very important, surplus of detritus outflows

Question 22

Describe seagrass community foodweb

Answer 22

Detritus based

Question 23

Rocky shore community food web

Answer 23

Herbivors and predation

Question 24

Describe coral reef community food web

Answer 24

Efficient nutrient recycling
Highest fixation of nitrogen
Zooxanthellae and turf algae most important primary producers
Many organisms feed on corals, their eggs or mucus

Question 25

Describe epipelagic food web

Answer 25

Complex and long Efficient energy transfer Size-structured Feed on different trophic levels

Question 26

What is hydrotermal vents foodweb characterized by?

Answer 26

Chemosynthesis

Question 27

Describe arctic food web

Answer 27

Key role of zooplankton

Question 28

Describe antarctic food web

Answer 28

Krill has key role

Question 29

What is top-down control?

Answer 29

Control of predators in highest trophic level | Increase of these causes a decrease in the next trophic level, and a consequent increase in the trophic level after that

Question 30

What is bottom-up control?

Answer 30

Producers regulate food web | Increase of production results in increased productivity for all higher trophic levels

Question 31

What is a trophic cascade?

Answer 31

Change in primary producers population or lower trophic level as a result of change in consumers' population

Question 32

What is a regime shift in trophic cascades?

Answer 32

Large scale transition between alternative states in ecosystems

Question 33

What is the most common method to assess food webs?

Answer 33

Stable-isotope analysis or, less, gut content analysis

Question 34

What does stable isotope analysis study?

Answer 34

Trophic relations and energy flows, trophic levels, source of nutrients

Question 35

What is stable isotope analysis?

Answer 35

Composition of a stable isotope is studied in the consumers tissue, and the difference between that and the prey's tissue, as a result of fractionation, is assessed. Based on the fact that heavier isotopes are conserved during chemical reactions

Question 36

What are problems with stable isotope analysis?

Answer 36

Sampling is done extensively | Individuals are sacrificed for studying

Question 37

What does analysis of gut content define?

Answer 37

Feeding behaviour Trophic level Predator-prey relationship

Question 38

What are problems of analysis of gut content?

Answer 38

Intensive work Different digestion times Large sample size required

Question 39

What is the aim of lipids and fatty acids assessment?

Answer 39

1) they serve as tracers of trophic relations | 2) reliable indicators of long-term diet