P2-Topic 7- Ecology 2022

Question 1

Define population

Answer 1

A species that occupy the same habitat

Question 2

Define habitat

Answer 2

The place in which an organism lives.

Question 3

Define community

Answer 3

Populations of different species interacting

Question 4

Define ecosystem

Answer 4

The interactions between the biotic and

abiotic factors in an area.

Question 5

What do food chains show?

Answer 5

Food chains show the feeding relationships of
different organisms and the flow of energy between
the organisms

Question 6

Define biomass

Answer 6

The total mass of living material

Question 7

What are trophic levels?

Answer 7

The stages in a food chain

Question 8

What do arrows in a food chain represent?

Answer 8

The direction of biomass transfer

Question 9

What types of organisms are primary producers?

Answer 9

Photosynthetic organisms like green plants and algae that trap energy from
the sun.

An organism that makes its own food

Question 10

What is a predator and prey 2

Answer 10

pred- A consumer that kills and eats other
animals.

prey-An animal that is killed and eaten by
another animal

Question 11

Describe the pattern of predators and prey in a stable community

Answer 11

The numbers of predators and prey rise and fall in cycles

Question 12

Why are producers the first trophic level? 2

Answer 12

● Producers provide all biomass for the food
chain (production of glucose via
photosynthesis).
● The rest of the food chain involves the transfer
of this biomass.

Question 13

What piece of apparatus is used to measure the

abundance and distribution of organisms in an area?

Answer 13

quadrat

Question 14

What piece of apparatus is used to study
the distribution of organisms across a
gradient?

Answer 14

Belt transect

Question 15

How is the arithmetic mean calculated?

Answer 15

Sum of each number of each organism

/the total number of each type of organism.

Question 16

Describe how materials cycle through the living and non-living components of an ecosystem 4

Answer 16

● Organisms take in elements from their surroundings e.g. soil, air.
● Elements converted to complex molecules which become biomass.
● Elements transferred along food chains.
● Elements returned to environment during excretion and
decomposition of dead organisms.

Question 17

Give 3 molecules which are cycled through

ecosystems

Answer 17

Oxygen, carbon dioxide and water

Question 18

Describe the carbon cycle 4

Answer 18

• Plants fix carbon dioxide into organic molecules during photosynthesis.
• The organic carbon-containing molecules are passed onto organisms
  that eat the plants.
• Carbon dioxide is released back into the atmosphere by respiration
  from animals and plants.
• Burning fossil fuels also releases carbon dioxide into the atmosphere.

Question 19

Why is the carbon cycle important?

Answer 19

Carbon-containing molecules such as
glucose are important for living organisms to grow and provide energy
for vital functions within cells

Question 20

Describe the water cycle 4

Answer 20

• Water from lakes and oceans evaporates.
• The evaporated water condenses into clouds and returns to earth as precipitation.
• The water from precipitation is useful for life on land.
• The water then returns to rivers and oceans through
  surface runoff.

Question 21

Why is the water cycle important?

Answer 21

Living organisms require water and the
water cycle provides organisms on land
with a continuous supply of water

Question 22

Why are microorganisms important for the cycling of

materials through an ecosystem?2

Answer 22

Microorganisms (bacteria and fungi) return carbon to the environment by releasing carbon dioxide through respiration while they decompose dead matter

.The decomposition of dead matter in soil returns mineral ions to the environment for other organisms to use e.g. plants use mineral ions for growth

Question 23

decomposition

Answer 23

4.7.2.3

62 flash

Question 24

Decomposition

Answer 24

breakdown of dead material into simple organic matter

Question 25

how decomposers break down dad matter

Answer 25

release enzymes that catalyses the breakdown of dead material into smaller molecules

Question 26

2 types of decomposition

Answer 26

aerobic decomposition

anaerobic decomposition

Question 27

factors that affect the rate of decomposition 3

Answer 27

oxygen availability - for aerobic respiration in decomposers’
↑↑ ↓↓

temperature

water content(soil)

Question 28

why can decomposition still occur in the absence of oxygen

Answer 28

some respire anaerobically

but the rate is slower as it producers less energy

Question 29

how soil water content affects the rate of decomposition 3

Answer 29

grow faster in conditions with water as needed for
respiration
Water also makes food easier to digest

waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases

Question 30

why does decomposition require water

Answer 30

required for the secretion pf enzymes and absorption of dissolved molecules

Question 31

how temperature affects the rate of decomposition

Answer 31

optimum temp 50’
low temp, enzyme work sow, rate decreases

high temp, enzyme denature, decomposition stops

Question 32

how is rate of change calculated

Answer 32

change in time

Question 33

what is compost and used 2

Answer 33

when biological material decays

natural fertiliser for growth of crops/garden plants

Question 34

describe how biogas generators work 2

Answer 34

provide methane gas for fuel by anaerobic decomposition in animal waste

cant be stored as a liquid so used immediately