Topic 9- Ecosystems And Material Cycles

Question 1

definition of individual

Answer 1

A single organism

Question 2

definition of population

Answer 2

All the organisms of one species in a habitat

Question 3

definition of community

Answer 3

All the organisms of different species living in a habitat

Question 4

definition of ecosystem

Answer 4

A community of organisms along with all the non-living (abiotic) conditions

Question 5

definition of interdependent

Answer 5

When organisms depend on each other for things like food and shelter

Question 6

explain what abiotic factors are

Answer 6

• Temperature
• Amount of water
• Light intensity
• levels of pollutants

Question 7

explain what biotic factors are

Answer 7

• competition

* Predation

Question 8

how to use quadrats

Answer 8

1) Place a 1 m² quedrat on the ground at a random the first sample area.
2) Count all the organisms you’re interested in within the quadrat.
3) Repeat steps 1 and 2 lots of times.
4) Work out the mean number of organisms per quadrat within the first sample area.
5) Repeat steps 1 to 4 in the second sample area.
6) Finally compare the two means. E.g. you might find a mean of 2 daisies per m² in one area, and 22 daisies per m² (lots more) in another area

Question 9

pyramids of biomass

Answer 9

•shows how much the creatures would weigh if you put them together

• first level is the producer
• second level is the primary consumer and so on

Question 10

equation for efficiency

Answer 10

Efficiency= energy transferred to next level/ energy available at previous level x 100

Question 11

explain how humans affect biodiversity

Answer 11

• fertilisers can leach into water and cause eutrophication
• fish farming
• introduction of non-indigenous species

Question 12

Conservation

Answer 12

Conservation methods:
•protecting a species natural habitat
•protecting species in safe areas outside natural habitat (eg.zoos)
•the use of seed banks

Question 13

definition of reforestation

Answer 13

Reforestation is when land where a forest previously stood is replanted to form a new forest

Question 14

name some benefits of maintaining biodiversity

Answer 14

• protecting the human food supply
• ensuring minimal damage to the food chains
• providing future medicines
• cultural aspect
• ecotourism
• providing new jobs

Question 15

name some biological factors which affect the level of food security

Answer 15

• increasing consumption of meat and fish
• environmental changes caused by humans
• sustainability
• new pests and pathogens

Question 16

explain the carbon cycle

Answer 16

-

Question 17

explain the water cycle

Answer 17

-

Question 18

explain the nitrogen cycle

Answer 18

-

Question 19

indicator species

Answer 19

Some organisms are very sensitive to change and so can be studied to see the effect of human activities

Question 20

water pollution

Indicator species

Answer 20

-if raw sewage containing nitrates are released into a river the microorganisms increase and use up the oxygen

Some invertebrate are good indicators for water pollution as they’re very sensitive.

Eg. If you find Stonefly larvae in a river it indicates the water is clean

Question 21

air pollution

Indicator species

Answer 21

Air pollution can be monitored by looking at particular types of lichen

As they’re sensitive to the concentration of sulphur dioxide

Question 22

name the factors which affect the rate of decomposition

Answer 22

• temperature
• water content
• oxygen availability

Question 23

definition of food preservation

Answer 23

•the process to slow decomposition

• storing food in the fridge or freezer
• storing food in air tight containers
• drying food (removes water)

Question 24

what are the ideal conditions for decomposition?

Answer 24

Decomposition is fastest in warm, moist conditions with plenty of oxygen available

Question 25

how to calculate the rate of decomposition

Answer 25

-find the gradient on a graph