B16: Energy and Biomass in Food Chains and Natural Cycles

Question 1

What do green plants and algae use to absorb sun energy.

Answer 1

Chlorophyll

Question 2

How does light energy add to a plant’s biomass?

Answer 2

Light energy - chemical energy in the bonds of glucose molecules that are made.

Question 3

Pyramid of Biomass

Answer 3

A model of the mass of biological material in the organisms at each level of a food chain.

Question 4

Reasons why the pyramid of biomass gets smaller.

Answer 4

> not all of an organism is eaten
biomass lost in faeces.
biomass lost in respiration.

Question 5

Biomass

Answer 5

Biological material from living or recently living organisms.

Question 6

Wet Biomass

Answer 6

Biomass with water

Question 7

Dry Biomass

Answer 7

Biomass without water.

Question 8

Why do carnivores have to eat less often than herbivores?

Answer 8

Meat is easier to digest than plants which herbivores can only eat part of (the rest is expelled as faeces), so carnivores have to eat less regularly.

Question 9

How does movement use energy?

Answer 9

The muscles use energy to contract and get warm.

Question 10

How is energy lost in maintaining a constant body temperature?

Answer 10

The body produces heat from the energy to maintain body temperature.

Question 11

Why is eating meat less energy efficient than eating plants?

Answer 11

Because for every trophic level 90% of energy is lost.
Plant-animal-human=1%
Plant-human= 10%

Question 12

Two ways to increase animal biomass faster.

Answer 12

> limiting movement so more energy goes towards producing larger biomass.
controlling the temperature of the room so no energy is lost through keeping warm.

Question 13

What is the main source of energy for most communities of living organisms on earth?

Answer 13

Radiation from the sun.

Question 14

Advantages of Battery Farming (chicken for meat and eggs)

Answer 14

> Lots of chickens are kept in a small space.
Little/no food waste.
Little energy wasted due to movement/heat loss.
Maximum weight gain/number of eggs laid.
Cheap eggs/chicken meat.

Question 15

Disadvantages of Battery Farming (chicken for meat and eggs)

Answer 15

> Chickens are unable to behave naturally - may be debeaked and cannot perch.
Large Barns need heating and lighting.
Chicken legs may break as their bones are unable to car-
ry weight of rapidly growing bodies.
Risk of disease as so many birds are packed so closely
together.

Question 16

Advantages of Free Range Chicken rearing

Answer 16

> Chickens live a more natural life.
There are no heating/lighting costs.
Less food needs to be supplied as the chickens can find it
themselves.
Farmers can charge more money for free-range eggs/
chickens.

Question 17

Disadvantages of Free Range Chicken rearing

Answer 17

> Chickens are more vulnerable to weather and predators.
More land is needed per bird.
Eggs cannot be collected automatically so farmers have
to employ someone to fetch the eggs.
Fewer eggs are laid (especially in the winter when it is
cold and dark for longer periods of time).

Question 18

Advantages of Intensive farming for beef

Answer 18

> Uses the male calves produced by dairy cows.
Weaning takes place for 8 weeks and then the farmer
knows exactly how much food each calf needs.
Balance of nutrients in food changes as the calf grows to
maximise its growth.
Kept indoors so that energy lost though movement and
heat loss can be kept to a minimum - calves can gain as
much as 1.5kg a day!
Cheap meat

Question 19

Disadvantages of Intensive farming for beef

Answer 19

> Feed stuff must be bought and it can be expensive.
The cowsheds need care and cleaning.
The cowsheds need to be heated and lit.
Unnatural and Inhumane.

Question 20

Advantages of free range cattle farming

Answer 20

> Calves are weaned naturally and they stay with their mothers for up to 6 months.
Feeding on grass or food which is grown by the farmer means that there is no contamination (eg. BSE).
Cattle can behave naturally and live a relatively natural life.

Question 21

Disadvantages of free range cattle farming

Answer 21

> Animals may take slightly longer to gain weight as they are moving more actively - but they are less stressed.
More land is needed to provide grazing , hay and silage.

Question 22

Why are fish stocks becoming so low?

Answer 22

Over fishing is depleting the numbers of breeding fish left in the sea.

Question 23

Ways of controlling fish stocks

Answer 23

> Bigger house in fish nets to only catch larger fish.
Bans on fishing during the breeding season.
Strict quotas.
No fishing zones.

Question 24

What is the problem with fishing quotas?

Answer 24

Throwing dead fish back into the sea does nothing to conserve the population.

Question 25

Mycoprotein

Answer 25

A food based on the fungus Fusarium that grows and reproduces rapidly. (quorn).

Question 26

Decomposers

Answer 26

Microorganisms that break down waste products and dead bodies.

Question 27

Conditions needed for decay

Answer 27

> Warmth
Moisture
Oxygen

Question 28

Detritivores

Answer 28

Organisms that feed on organic waste from animals and the dead bodies of animals and plants.

Question 29

What are the waste products of decomposers?

Answer 29

> Carbon Dioxide
Water
Nutrients

Question 30

Why are decomposers so important?

Answer 30

Because they return the nutrients that the plant absorbs from the soil whilst growing.

Question 31

Two advantageous uses of decomposers

Answer 31

> Sewage Treatment Plants: Break down bodily waste so that its safe to release into rivers and the sea.
Compost Heaps: Breaks downs organic waste into fertiliser.

Question 32

Carbon Sinks

Answer 32

Something that uses more CO2 than it produces.

Question 33

How is carbon removed from the environment?

Answer 33

1. Green plants and algae remove Carbon Dioxide from the atmosphere to use it to make carbohydrates, proteins and fats. (biomass)
2. Carbon is then passed on to the animals that eat the plants to make up the animal’s biomass.
3. Continues in this way.

Question 34

How is carbon returned to the atmosphere?

Answer 34

> Through organism’s respiration, ready to be taken in by green plants and algae.
Combustion of fossil fuels and wood.

Question 35

Combustion Equation:

Answer 35

Fossil Fuel/ Wood + Oxygen -> Carbon Dioxide + Water (energy)