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Bio B4-B6 > B4.1 - Ecosystems > Flashcards

B4.1 - Ecosystems Flashcards

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1
Q

What do arrows on a food chain show?

A
  • the transfer of biomass

- transfer of energy

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2
Q

what is the difference between a food chain and a food web?

A

a food chain is a small section of the whole food web

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3
Q

what do food chains show?

A

the feeding relationship in an ecosystem

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4
Q

what are producers?

A

organisms that make their own food through photosynthesis

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5
Q

what are primary consumers?

A

animals that eat plants or algae (herbivores)

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6
Q

what are secondary consumers?

A

carnivores that eat herbivores

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7
Q

what is a tertiary consumer?

A

a carnivore that eats other carnivores

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8
Q

what are apex predators?

A

carnivores that have no other predators

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9
Q

what are decomposers

A

organisms that get energy from feeding on dead materials

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10
Q

what are consumers?

A

organisms that cannot make their own food and so have to eat other organisms

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11
Q

what are trophic levels?

A

each step in the food chain (where they feed)

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12
Q

what is a community?

A

organisms living within an ecosystem

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13
Q

define population

A

the total number of organisms of each species

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14
Q

what happens when an organism grows?

A

increases its biomass

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15
Q

state the factors affecting ecosystems and give a brief description

A
  • biotic (living - beech trees, squirrels, hedgehogs)

- abiotic (nonliving - amount of rainfall, temperature of ecosystem)

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16
Q

what biotic factors affect communities? - 4

A
  • food availability
  • breeding partners
  • COMPETITION
  • new pathogens
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17
Q

how does light intensity affect communities?

A
  • greater light available = greater plant success

- plants adapt for maximum absorption (larger leaves in low light)

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18
Q

how does temperature affect communities?

A
  • affects enzymes controlling metabolic reactions

- plants develop faster

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19
Q

what type of animals are affected by their external environments?

A

ectotherms (lizards)

rely on the sun to warm up

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20
Q

how does low moisture level affect plants?

A
  • causes plants to wilt (low turgor pressure)
  • water needed to keep cells turgid
  • affects photosynthesis
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21
Q

what does the pH of soil affect?

A
  • biological activity in soil

- availability of certain minerals

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22
Q

what kind of plants grow better in acidic soils?

A

ferns

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23
Q

what do plants need to survive? (5)

A
  • light
  • water
  • carbon dioxide
  • minerals
  • space
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24
Q

what do animals need to survive?

A
  • food
  • water
  • breeding partner
  • space (territory)
  • shelter
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25
Q

define population

A

the number of organisms of each species living in an area

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26
Q

what is interdependence within a community?

A

how different organisms depend on each other

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27
Q

what are ecological relationships?

A

interactions between organisms

28
Q

what are the three main types of ecological relationships

A
  • predation
  • mutualism
  • parasitism
29
Q

what is predation the relationship of?

A
  • relationship between predator and prey
  • size of predator population directly affects prey population
  • cyclic relationship
30
Q

what is mutualistic relationship?

A
  • both organisms benefit
31
Q

give an example of a mutualistic relationship

A

bees taking pollen from plants

bees can make honey, plants become fertilised

32
Q

what is a parasitism relationship?

A

one organism gains (parasite), other suffers (host)

33
Q

give an example of a parasitism relationship

A

tapeworms in a human’s digestive system

34
Q

what is commensalism?

A

one organism benefits from, but the other one is unaffected

35
Q

what is an example of a commensalistic relationship?

A

tree frogs use plants as protection

36
Q

what is a biotic factor?

A

a factor relating to animals (ie. competition of mating)

37
Q

what is an abiotic factor?

A

a factor which is not living? (ie. rainfall)

38
Q

why do food chains not exceed 4/5 tertiary levels?

A

not enough energy can be transferred to sustain life processes) - because of 10% rule

39
Q

what does a pyramid of numbers show?

A
  • the population at each trophic level (how many there are)
40
Q

what do pyramid of numbers not take into account?

A

the size of the organism present

41
Q

how do scientists calculate biomass?

A
  • get dead organism
  • dry the organism in a kiln (evaporate water mass)
  • then measure it

CALLED DRY MASS

42
Q

how do scientists calculate the total biomass at each trophic level?

A

measure average mass of each organism and multiply by the number of organisms present

43
Q

state three reasons biomass is lost between trophic levels

A
  • not all organism is eaten (animal bones/ plant roots)
  • biomass is used during respiration
  • some parts of organism cannot be digested (hair/teeth) - egestion
  • released as waste products (excretion/ urine)
44
Q

what is the nutrient cycle?

A

the process in which materials are passed between biotic and abiotic components of an ecosystem

45
Q

what is carbon used to make?

A

GLUCOSE which makes…

  • carbohydrates
  • fat
  • dna
  • proteins
46
Q

in what form can organisms use nitrogen?

A

when part of a compound (like a nitrate)

47
Q

why do organisms use nitrogen?

A
  • DNA

- proteins

48
Q

Apart from providing water to organisms, describe another benefit of then water cycle

A

transports nutrients (helps replenish nutrients in different habitats)

49
Q

how is carbon removed from the atmosphere?

A
  • photosynthesis

- when animals eat plants

50
Q

how is carbon released back into the atmosphere? - 3

A
  • respiration
  • decomposition
  • burning fossil fuels
51
Q

how does the level of atmospheric carbon vary throughout 24 hours?

A
  • decreases during daytime (photosynthesis)

- increases during nighttime (no photosynthesis, but respiration continues)

52
Q

what are decomposers?

A

microorganisms which break down or decay dead organic matter at a microscopic level

53
Q

how do decomposers help the nutrient cycle?

A

release nutrients (can be recycled)

54
Q

what are detritivores?

A

small animals which shred organic material to small pieces (create larger surface area for decomposers)

An organism that eats DOM and digests internally for nutrients

55
Q

how do decomposers release nutrients?

A
  • bacteria and fungi release enzymes
  • break down substances in the organic materials
  • absorb soluble nutrients + use them for growth + energy store
  • some others released into soil // many bacteria/fungi eaten by other organisms, resulting in the nutrients being passed on
56
Q

how do temperatures affect rate of decomposition?

A
  • too high = enzymes used by microorganisms denature (they die)
  • too low = rate of enzyme controlled reactions too slow
57
Q

how does lack of water in environments affect rate of decomposition?

A
  • not enough water = reactions slow down/stop
58
Q

how does lack of oxygen affect decomposition?

A

decreases, oxygen needed for microorganism to respire (so cannot survive)

59
Q

what is the equation to calculate the rate of decay of material?

A

rate of decay (g/day) = change in mass (g) / time (day)

60
Q

give 3 examples of detritivores

A
  • earthworm
  • woodlouse
  • maggot
61
Q

what 3 factors affect rate of decomposition?

A

water level, temperature, oxygen level

62
Q

Describe how water is cycled through an ecosystem.

A

Water evaporates from rivers and lakes and from transpiration
Water condenses as clouds
Water is returned through precipitation

63
Q

Describe how carbon is cycled through an ecosystem.

A

Carbon dioxide is fixed through photosynthesis
Respiration releases carbon dioxide
Decomposition releases carbon dioxide
Combustion releases carbon dioxide

64
Q

Describe how nitrogen is cycled through an ecosystem.

A

Nitrogen is fixed by lightning and nitrogen-fixing bacteria.
Denitrifying bacteria release nitrogen into the air from nitrates in the soil.
Denitrifying bacteria covert nitrates in soil into nitrites and nitrites to ammonia.
Nitrifying bacteria convert ammonia in soil into nitrates.
Nitrates in soil taken up by plants and combined with carbohydrates to make plant proteins.
Plant proteins either eaten by other animals to form animal protien or die and decompose to release ammonia into soil.
Animals excrete ammonia and die and decompose to release ammonia into soil.

65
Q

How is fungal infections in plant spread

A
  • spread by wind
  • spores
  • enters leaves through the stomata

Bio B4-B6 (9 decks)

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