Ecology and environment

Question 1

population

Answer 1

All the members of a single species living in a geographical area

Question 2

Habitats

Answer 2

The place where organisms live

Question 3

community

Answer 3

All organisms that live in a single habitat

Question 4

abiotic factors

Answer 4

non living factors affecting the distribution or population size of organisms

Light, PH, temperature

Question 5

Biotic factors

Answer 5

Living factors the affect the distribution of population size of organisms

Predators, food availability , infection from pathogens and competition from other organisms

Question 6

Practical investigate the population size of organisms using quadrats

Answer 6

1. Mark out two 10m2 areas in different place
   2.Use number randomiser to randomly select co ordinates to remove bias
2. Lay quadrat on the left corner of co ordinate and count amount of select organisms in quadrat
3. Repeat ten times then find the mean

Question 7

ecosystem

Answer 7

interactions between biotic and abiotic factors in the area

Question 8

biodiversity

Answer 8

variation between organisms

Question 9

abiotic factors that affect animal population size

Answer 9

-temperature
- water availiability

Question 10

biotic factors that affect the population size

Answer 10

• the number of predators
• the presence of disease or pathogens
• competition from other organisms

Question 11

abiotic factors that affect communities

Answer 11

• Light intensity
• temperature
• Soil PH
• Moisture levels

Question 12

biotic factors that affect communities

Answer 12

• number of predators
• food availiability
  -disease
• Human activity

Question 13

What is a producer?

Answer 13

An organism that makes its own food

Question 14

What is a primary consumer?

Answer 14

an organisms that feeds on producers

Question 15

What is a secondary consumer?

Answer 15

an organism that feeds on primary consumers

Question 16

Biomass

Answer 16

the dry mass of all the living organisms in an area

Question 17

Why is dry mass used for biomass?

Answer 17

Because wet mass varies as the volume of water in the organism varies

Question 18

How do u calculate the efficency of biomass transfer?

Answer 18

efficiency= energy transferred/total energy availiable x 100

Question 19

Why are biomass transfers not 100% efficient?

Answer 19

energy is lost through
- egestion
- excretion
-respiration
-the production of inedible bones and shells

Question 20

egestion

Answer 20

removal of faeces

Question 21

excretion

Answer 21

removal of METABOLIC waste

Question 22

How does the efficency of biomass transfers affect the number of trophic levels in a biomass pyramid?

Answer 22

The less efficent the transfers, the fewer trophic levels and the fewer organisms in higher trophic levels

Question 23

What is the difference between a food web and chain?

Answer 23

Food webs dhow interactions of multiple different food chains.
Food chains show one path of food dependencies

Question 24

Molecules that are cycled through ecosystems

Answer 24

• oxygen
  -carbon
  -water

Question 25

How is carbon dioxide cycled through an ecosytem

Answer 25

• CO2 is fixed through photosynthesis –> respiration releases CO2–> Decomposition releases CO2 –> combustion releases CO2

Question 26

How is nitrogen cycled through and ecosystem?

Answer 26

Nitrogen is fixed by lightning, the haber process and bacteria –> decomposers break down dead matter into ammonia –> nitrifying bacteria convert ammonia into nitrites and nitrates –> denitrfying bacteria release nitrogen back into the atmosphere

Question 27

what do decomposers break down

Answer 27

dead matter into ammonia

Question 28

what does nitrifying bacteria do

Answer 28

convert ammonia into nitrites and nitrates

Question 29

decomposers

Answer 29

organisms that release enzymes which catalyse the break down of dead plant and animal material into ammonia

Question 30

Denitrifying bacteria

Answer 30

bacteria that convert nitrates in the soil into nitrgogen gas