Populations in ecosystems (Topic 7C)

Question 1

define ecology

Answer 1

The relationship of organisms with their living and nonliving environment

Question 2

define population

Answer 2

all members of a species found in a particular area at a particular time

Question 3

define community

Answer 3

all the populations in the ecosystem

Question 4

define ecosystem

Answer 4

a community and the physical environment

Question 5

define abiotic factors

Answer 5

the non-living things in an ecosystem

Question 6

define biotic factors

Answer 6

the living things in an ecosystem

Question 7

define producer

Answer 7

any plant that manufactures food by photosynthesis

Question 8

producers are also known as…

Answer 8

autotrophs

Question 9

define consumer

Answer 9

organisms that eat producers and/or other animals

Question 10

define decomposer

Answer 10

organisms that break down dead organisms making their materials available to other living things

Question 11

decomposers are also known as…

Answer 11

detrivores

Question 12

define habitat

Answer 12

the place in the ecosystem where an organism lives

Question 13

define niche

Answer 13

an organisms role in the ecosystem

Question 14

define biome

Answer 14

an area on the earth identified by climate, plant and animal life

Question 15

define the carbon cycle

Answer 15

the movement of carbon in nature

Question 16

define the nitrogen cycle

Answer 16

the movement of nitrogen in nature

Question 17

what is the method for mark, release, recapture?

Answer 17

1. Capture in a non-harmful way
2. Mark in a way that is non toxic and doesnt impact on survival.
3. Release back to habitat & allow time for intermingling
4. Recapture

Question 18

what is the equation that goes alongside mark, release, recapture?

Answer 18

(total in first x total in second) / no. of individuals recaptured

Question 19

when grass is grown in a field fewer nitrate ions are lost than when the field is left with bare soil. explain why
(2 marks)

Answer 19

the presence of grass causes less nutrients to be leached

Question 20

describe the role of microorganisms after a field of crops is ploughed
(5 marks)

Answer 20

1. microorganisms break proteins down
2. ammonification
3. conversion to nitrates
4. by nitrifying bacteria
5. nitrates absorbed into roots of new crops

Question 21

why are phosphates needed by a growing plant?

3 marks

Answer 21

1. for production of phospholipids in cell membrane
2. synthesis of ATP
3. production of DNA

Question 22

why is it important for a farmer to reduce the leaching of nitrates?

Answer 22

fewer nitrates in the soil for the next crop requiring more application of fertiliser needed

Question 23

explain how the use of inorganic fertilisers on fields leading to a lake no longer having any plants or fish anymore

6 marks

Answer 23

the run off of fertilisers
leads to increased algae growth
increases competition for light
causing death of plants
which increases food supply for microorganisms
respiration of microorganisms used up oxygen
fish die die to lack of oxygen

Question 24

explain how including leguminous plants in a crop rotation reduces the need to use artificial fertilisers

2 marks

Answer 24

they contain nitrogen fixing bacteria in foods so when the die they add nitrogen containing compounds to the soil

Question 25

application of very high concentrations of fertiliser to the soil causes plants to wilt. explain why

2 marks

Answer 25

lower water potential in soil than in the plant which prevents roots from taking up water

Question 26

give the equation that links gross productivity and net productivity

Answer 26

net productivity = gross productivity- respiratory losses

Question 27

why is an animals mean energy expenditure higher in colder months

Answer 27

the temperature was colder so they needed more energy to maintain its body temperature by respiration

Question 28

interspecific competition is when…

Answer 28

organisms of the same species compete with each other for the same resources

Question 29

intraspecific competition is when….

Answer 29

organisms of different species compete with each other for the same resources

Question 30

predation is when…

Answer 30

an organism (the predator) kills and eats another (the prey)

Question 31

succession is…

Answer 31

the process by which an ecosystem changes over time

Question 32

primary succession happens on what kind of land?

Answer 32

newly formed or exposed land

Question 33

the species that is first to colonise a new land surface is called….

Answer 33

the pioneer species

Question 34

why can only the pioneer species grow on new land?

Answer 34

conditions are hostile and only this species is adapted to cope with these conditions

Question 35

how do pioneer species change the abiotic conditions?

Answer 35

they die and microorganisms decompose the dead organic material forming basic soil

Question 36

a climax community is…

Answer 36

the ecosystem is in a steady state with its most complex community of plants and animals

Question 37

secondary succession happens on…

Answer 37

land thats cleared of plants but where the soil remains
e.g. after a forest fire

Question 38

the climax community for a particular climate is called….

Answer 38

climatic climax

Question 39

conservation is…

Answer 39

the protection and management of species and habitats in a sustainable way

Question 40

what are 5 methods of conservation?

Answer 40

1. managment of succession
2. seed banks
3. captive breeding
4. fishing quotas
5. protected areas

Question 41

the carrying capacity is the….

Answer 41

maximum stable population size of a species that an ecosystem can support