Biomass transfer through an ecosystem

?
What is the ultimate source of energy?
The sun
1 of 24
What is a trophic level?
Each level of each food chain
2 of 24
What is the first trophic level?
The producer
3 of 24
What are the trophic levels after the producer?
Consumers (primary consumer, secondary consumer and so on)
4 of 24
Why is there never really any more than 4 trophic levels?
Because there is not sufficient biomass and energy stored to support any further consumers
5 of 24
Why are decomposers important in food webs?
They help return the nutrients from the dead organisms back into the food web again by consuming them, then being consumed themselves
6 of 24
What is biomass?
The mass of living material present in a particular place or in a particular organism
7 of 24
How do you calculate the biomass of a trophic level?
The biomass present in each organism multiplied by the total no. of organisms
8 of 24
What does a biomass pyramid represent? What does it not take into account?
The biomass at a particular moment in time and doesnt take into account seasonal changes
9 of 24
How do scientists effectively measure biomass of an organism?
It has to be the dry mass of an organism so the organism has to be baked at 80'c till all the water has evaporated
10 of 24
Name some issues with measuring biomass effectively (removing water)
Orgamisms have to be killed, also to minimise destruction of the organisms, a relatively small sample is used, making it less representative
11 of 24
What is biomass measured in?
Grams per metre squared
12 of 24
Why is the trophic level below nearly always bigger than the trophic level above?
Biomass consists of all the cells bones, tissue etc, when organisms eat, only a proportion of that is made into tissues for next trophic level to eat, a lot of it used in respiration etc
13 of 24
What is the energy available at each trophic level measured in and why?
Kilojoules per square metre per year to allow for certain changes like photosynthetic production or consumer feeding patterns etc
14 of 24
What is the efficiency from which biomass is transferred through trophic levels called?
Ecological efficiency
15 of 24
What percentage of the sun is transferred into biomass by producers?
1-3%
16 of 24
Why is this?
90% is reflected, some light is unsuitable wavelength, other limiting factors to photosynthesis like water availability slows down photosynthesis and so less turned into biomass, energy lost for reactions
17 of 24
What is the net production in a trophic level?
The total energy available for the next trophic level
18 of 24
How do you work out net production?
Total (gross) production - respiratory losses
19 of 24
What percentage of biomass in food do consumers convert into tissues
At most 10%
20 of 24
Name a few reasons why only 10% of biomass from food is converted into tissues
Not all of food is eaten (bones), not all of food is digested (cellulose) & pooped out, energy transferred into environment (metabolic heat), lost in excretion (e.g. urine)
21 of 24
How do you work out ecological efficiency?
(Energy/biomass after transfer/ energy/biomass after transfer) X 100
22 of 24
Give an example of humans manipulating biomass through ecosystems
Agriculture, giving conditions that favour organism, remove threat and competition, producing simple food chains
23 of 24
How and why have humans created simple food chains?
No predators, only 2/3 trophic levels, ensuring minimum energy loss go more energy and as much as possible converted into biomass for consumption
24 of 24

Other cards in this set

Card 2

Front

What is a trophic level?

Back

Each level of each food chain

Card 3

Front

What is the first trophic level?

Back

Preview of the front of card 3

Card 4

Front

What are the trophic levels after the producer?

Back

Preview of the front of card 4

Card 5

Front

Why is there never really any more than 4 trophic levels?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Ecosystems resources »