Bio 20: Section 1.2

Question 1

what is an ecosystem?

Answer 1

biotic & abiotic factors interacting (in time & space)

Question 2

the first trophic level provides all the ____________ required to fuel the other trophic levels

Answer 2

energy

Question 3

what is on the first trophic level? (always)

Answer 3

producers

Question 4

which trophic level contains producers?

Answer 4

the first

Question 5

what is on the 2nd trophic level?

Answer 5

herbivores, primary consumers

Question 6

what is on the 3rd trophic level?

Answer 6

carnivores, secondary consumers

Question 7

what is on the 4th trophic level?

Answer 7

carnivores, tertiary consumers

Question 8

why are food chains not likely to go beyond 4-6 trophic levels?

Answer 8

b/c the 2nd law of thermodynamics states that energy is lost in other forms
so, as energy is transferred several times b/w trophic levels, more and more energy is lost

Question 9

a simple model that shows the linear pathways through which energy is transferred from producer to top carnivore up the trophic levels

Answer 9

food chain

Question 10

a model of energy transfer in an ecosystem that shows the connections among food chains

Answer 10

food web

Question 11

what % of energy is transferred from one trophic level to another?

Answer 11

10%

Question 12

what are two ways that energy is lost to the environment?

Answer 12

passing of indigestible matter that decomposers break down (creates heat)

generation of heat through biological processes

Question 13

what does cellular respiration do when it comes to consuming food?

Answer 13

it breaks down the energy content in the food so that it can be used by the organism that’s consuming it

Question 14

why is less energy transferred form one trophic level to another?

Answer 14

2nd law of thermodynamics states that systems are not 100% efficient and energy will be lost as it is transferred from one level to another

Question 15

where are decomposers on the trophic chain?

Answer 15

any trophic level, but the first, b/c they can’t be producers

Question 16

why can’t decomposers be producers?

Answer 16

b/c they get their energy from breaking down the contents of dead organisms and recieve their food from there, while producers get their energy from the Sun or chemicals (ex. hydrogen sulfide)

and also, decomposers are consumers

Question 17

if a worm species on the 2nd trophic level decreases, what happens to the small birds on the 3rd trophic level?

Answer 17

the birds will starve and decrease in population

Question 18

a moose consumes 3500 kJ of energy from a balsam fir tree. Estimate how much of this energy would be available to a wolf that consumes the moose.

Answer 18

350 kJ

Question 19

what are the 3 types of ecological pyramids?

Answer 19

numbers
biomass
energy

Question 20

compares population number between trophic levels
represents the relative number of organisms at each link (or each trophic level) in a food chain

Answer 20

pyramid of numbers

Question 21

in many ecosystems, organisms at higher trophic levels are ___________ in number than organisms at lower trophic levels

Answer 21

lesser

Question 22

where organisms at a lower trophic level are lesser in number than organisms at a higher trophic level

Answer 22

inverted pyramid of numbers

Question 23

in some ecosystems, a smaller number of ___________ organisms at a lower trophic level can support a larger number of smaller organisms at higher trophic levels

Answer 23

large

Question 24

is a large tree is at the lowest trophic level, can its biomass be more than that of insects at high trophic levels?

Answer 24

yes

Question 25

the relative dry mass in grams per square meter of living or once living organisms in an ecosystem

Answer 25

biomass

Question 26

there is less biomass at the first trophic level than at the second trophic level

Answer 26

inverted pyramid of biomass

Question 27

shows the transfer of energy from one trophic level to the next

Answer 27

pyramid of energy

Question 28

while the estimate for energy loss is 10%, what is the range for the actual effiecieny?

Answer 28

5% to 20%

Question 29

in all ecosystems, there is _______ energy at the higher trophic levels than at lower trophic levels

Answer 29

less

Question 30

true or false: there are inverted pyramids of energy

Answer 30

false: there can never be less energy in a lower trophic level than in a higher one

Question 31

if there was such thing as an inverted pyramid of energy, which law would that be breaking?

Answer 31

the 1st law of thermodynamics