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biology > organisation of an ecosystem > Flashcards

organisation of an ecosystem Flashcards

1
Q

define population

A

a species that occupy the same habitat

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2
Q

define habitat

A

the place in which an organism lives

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3
Q

define community

A

populations of different species interacting

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4
Q

define ecosystem

A

the interactions between the biotic and abiotic factors in an area.

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5
Q

what do food chains show?

A

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

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6
Q

define biomass

A

the total mass of living material

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7
Q

what are trophic levels

A

the stages in a food chain

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8
Q

what do arrows in a food chain represent?

A

the direction of biomass transfer

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9
Q

describe a simple food chain

A

producer > primary consumer > secondary consumer > tertiary consumer

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10
Q

what is a producer?

A

an organism that makes its own food

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11
Q

what type of organism are primary producers?

A

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

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12
Q

what is a primary consumer?

A

an organism that feeds on producers

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13
Q

what is a secondary consumer?

A

an organism that feeds on primary consumers

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14
Q

what is a tertiary consumer?

A

an organism that feeds on secondary consumers

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15
Q

what is a predator?

A

a consumer that kills and eats other animals

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16
Q

what is prey?

A

an animal that is killed and eaten by another animal

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17
Q

describe the pattern of predators and prey in a stable community

A

the numbers of predators and prey rise and fall in cycles

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18
Q

why are producers the first trophic level?

A
  • producers provide all biomass for the food chain

- the rest of the food chain involves the transfer of the biomass

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19
Q

what piece of apparatus is used to measure the abundance and distribution of organisms in an area?

A

Quadrat

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20
Q

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

A

belt transect

21
Q

when considering the abundance of organisms, what is meant by the term “mean”

A

the average number of organisms

22
Q

how is the arithmetic mean calculated?

A

sum of each number of each organism/ the total number of each type of organism

23
Q

when considering the abundance of different organisms, what is meant by the term “mode”

A

the most populous organism

24
Q

when considering the abundance of organisms, what is meant by the term “median”?

A

the organism that represents the middle value when the numbers of each organism are arranged from lowest to highest

25
Q

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

A
  • organisms take in elements from their surroundings eg. soil and 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
26
Q

give 3 molecules which are cycled through ecosystems

A

oxygen, carbon dioxide and water

27
Q

describe the carbon cycle

A
  • 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
  • burnings fossil fuels also releases carbon dioxide into the atmosphere
28
Q

why is the carbon cycle important?

A

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

29
Q

describe the water cycle

A
  • 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
30
Q

why is the water cycle important?

A

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

31
Q

why are the microorganisms important for the cycling of materials through an ecosystem?

A

microorganisms return carob 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 eg. plants use minerals ions for growth

32
Q

what is meant by decomposition?

A

the breakdown of dead materials into simpler organic matter

33
Q

how do decomposers break down dead matter?

A

decomposes releases enzymes which catalyse the breakdown of dead material into smaller molecules

34
Q

what are the 2 types of decomposition?

A
  • aerobic decomposition (with oxygen)

- anaerobic decomposition (without oxygen)

35
Q

what factors effect the rate of decomposition?

A
  • oxygen availability
  • temperature
  • water content
36
Q

why is oxygen required for decomposition?

A

most decomposers require oxygen for aerobic respiration

37
Q

how does the availability of oxygen affect the rate of decomposition?

A
  • as oxygen levels increase, the rate of decomposition increases
  • as oxygen levels decrease, the rate of decomposition decreases
38
Q

why can decomposition still occur in the absence of oxygen?

A

some decomposers respire anaerobically but the rate of decomposition is slower as anaerobic respiration produces less energy.

39
Q

how does the soil water content affect the rate of decomposition?

A

decomposers require water to survive:

  • in moist conditions the rate of decomposition is high
  • in waterlogged soils there is little oxygen for respiration so the rate of decomposition decreases
40
Q

what does decomposition water?

A

water is required for the secretion of enzymes and absorption of dissolved molecules

41
Q

how does the temperature affect the rate of decomposition?

A

decomposes releases enzymes:

  • rate highest at 50degrees (optimum temp for enzymes)
  • lower temps, enzymes work too slowly, rate decreases
  • high temps, enzymes denature, decomposition stops
42
Q

how is the rate of change calculated when considering the decay of biological material?

A

rate of change = change in value/ change in time

43
Q

what is compost?

A

the nutrient-rich product of the rapid decay of waste biological material in optimum conditions set by gardeners and farmers.

44
Q

how is compost used?

A

used as natural fertilisers to promote growth of crops or garden plants.

45
Q

describe how biogas generators work

A

biogas generators provide methane gas for fuel through anaerobic decomposition that occurs in animal waste

46
Q

describe how environmental conditions affect communities

A
  • environmental conditions eg. temperature, soil pH, light intensity affect the abundance and distribution of organisms within communities
  • eg. rising global temps have been linked to the extinction of frog species
47
Q

how can different temperatures be bad for certain communities?

A
  • if the temp is too low, growth will be slower as organisms will use more energy to stay warm
  • if the temp is too high, organisms can die and water will become limited as evaporation increases
48
Q

how can change in water levels affect ecosystems?

A
  • animals may have to migrate to find water

- melting ice caps may destroy the habitats of some animals

49
Q

how can atmospheric gasses affect ecosystems?

A
  • some organisms cannot survive when certain gasses are present
  • polluted water can cause illness to animals that drink it.

biology (7 decks)

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