Food Webs & Food Chains

Question 1

what is a food web?

Answer 1

a model of an interlocking pattern of food chains that depicts the flow of energy and nutrients in two or more food chains; shows how matter and energy flow through an ecosystem from organism to organism

Question 2

what plays a role in food webs?

Answer 2

positive and negative feedback loops

Question 3

how do feedback loops affect food webs?

Answer 3

when one species is removed from or added to a specific food web, the rest of the food web can be affected

Question 4

what do the arrows in food webs indicate?

Answer 4

the direction of energy flow, they point to the organism taking in the energy

Question 5

what is transferred when one organism preys on another?

Answer 5

the matter (carbon, nitrogen, water, phosphorus) and energy (glucose, muscle tissue, etc.) are passed from the prey to the predator

Question 6

what is the difference between a food web and a food chain?

Answer 6

food chains show just one, linear path of energy and matter while food webs have at least two different, interconnected food chains

Question 7

webs show that organisms can exist:

Answer 7

at different trophic levels
grass → hare → owl (secondary consumer)
grass → grasshopper → robin → owl (tertiary consumer)

Question 8

food webs show how an increase or decrease in __________ will impact __________
give example

Answer 8

population size of a given species, the rest of the food web
increase in python population → decrease in frog and rat populations → increase in grasshopper population → decrease in corn

Question 9

what is the trophic cascade?

Answer 9

the removal or addition of a top predator has a ripple effect down through lower trophic levels

Question 10

what is an example of the trophic cascade?

Answer 10

a decline in the wolf population leads to an increase in the deer population which leads to overgrazing and a decline in trees