3.3- Energy Flow in Ecosystems

Question 1

How does energy flow through an ecosystem?

Answer 1

in a one-way stream from primary producers to various consumers

Question 2

What is a food chain?

Answer 2

a series of steps in which organisms transfer energy by eating and being eaten

Question 3

Example of a food chain:

Answer 3

Prarie ecosystem: grass > antelope > coyote (two-step chain)

Question 4

What is phytoplankton?

Answer 4

primary producers found in aquatic food chains (a mixture of floating algae)

Question 5

What is a food web?

Answer 5

a network of feeding interactions

Question 6

Why do we use food webs?

Answer 6

many animals eat more than one kind of food; links together all of the food chains in an ecosystem

Question 7

Each path you can trace through a food web is:

Answer 7

a food chain

Question 8

Decomposers convert:

Answer 8

dead material to detritus, which is then eaten by detritivores

Question 9

Decomposers’ process releases nutrients that:

Answer 9

can be used by primary producers

Question 10

Decomposers recycle nutrients in food webs, with out them:

Answer 10

nutrients would remain locked within dead organisms

Question 11

What is zooplankton?

Answer 11

diverse group of small swimming animals that feed on marine algae

ex: Krill

Question 12

Enviromental distubances (in food webs/ecosystems) can:

Answer 12

have dramatic effects; in southern ocean ecosystem, many animals depend directly or indirectly on krill; with sea ice melting fewer algae can grow, reducing krill population and consquently reducing pop. of other animals

Question 13

What is a trophic level?

Answer 13

each step in a food chain or web

Question 14

What is the 1st trophic level?

Answer 14

primary producers

Question 15

What are ecological pyramids?

Answer 15

show the relative amount of energy or matter contained within each trophic level in a given food chain or food web

Question 16

How to we use ecological pyramids?

Answer 16

to illustrate trophic levels in an ecosystem

Question 17

What are the 3 types of ecological pyramids?

Answer 17

pyramids or energy, biomass, and numbers

Question 18

What do pyramids of energy show?

Answer 18

the relative amount of energy avaliable at each trophic level in a food chain/web

Question 19

Why is only a small portion of the energy that passes through any given trophic level is ultimatley stored in the bodies of organisms of the next level?

Answer 19

because organisms expend much of the energy they acquire on life processes and most of remaining nergy is released in to the environment as heat

Question 20

How much energy that is avaliable within a trophic level is transferred to the next?

Answer 20

about 10%, but it can vary

ex: primary producers- 100% 1st level consumers- 10% 2nd level consumers- 1%

Question 21

The more levels that exist between a producer and a consumer:

Answer 21

the smaller the % of the original energy from producers is avaliable to that consumer

Question 22

What is biomass?

Answer 22

the total amount of living tissue within a given trophic level

Question 23

How is biomass measured?

Answer 23

in grams of organic matter per unit area

Question 24

amount of biomass a trophic level can support is determined by:

Answer 24

amount of energy avaliable

Question 25

What does a pyramid of biomass show:

Answer 25

relative amount of living organic matter avaliable at each trophic level

Question 26

What does a pyramid of numbers show?

Answer 26

relative number of individual organisms at each trophic level

Question 27

What are the 2 shapes of pyramids of numbers?

Answer 27

number of individuals decrease at each trophic level, or 1 large primary producer (number of indiviuals increase- so pyramid is turned upside down)

Question 28

Food chain vary in…

Answer 28

length

two step food chain, four step food chain

Ex: prarie ecosystem: buffalo grass, antelope, coyote

Question 29

How did wolves introduced in Yellowstone affect the ecosystem?

Question 29

Energy flow in a food web is:

Answer 29

multidirectional

Question 30

How are prarie dogs a keystone species?