ecology and the environment 4.1, 4.2, 4.5, 4.6, 4.7, 4.8, 4.9, 4.10, 4.13, 4.14, 4.15, 4.11B Flashcards

1
Q

what’s an ecosystem?

A

system or area where organisms interact with their physical environment

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2
Q

what’s a producer?

A

organisms which make their own food
photosynthesising plants

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3
Q

what’s a consumer?

A

an organism which eats other living things
animals

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4
Q

what’s a decomposer?

A

organisms which secrete digestive enzymes to decay dead organic matter to obtain food
they help to recycle nutrients

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5
Q

what’s abiotic?

A

non-living factor

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6
Q

whats biotic?

A

living factor

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7
Q

whats habitats?

A

places where specific organisms live

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8
Q

practical
measuring the living organisms in an ecosystem:

A

use quadrat
use a 50cm by 50cm square that has an area of 0.25cm^2
- calculate the total area of the habitat
- place the quadrant on the ground using random sampling
- count the number of individuals of the chosen pieces inside the square
- calculate the average number of individuals in the quadrant
- calculate how many quadrants fit into the total area
- multiply the number of quadrats by the average number of individuals

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9
Q

what’s a population?

A

the total number of individuals of one species in a particular habitat at a particular time

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10
Q

whats random sampling and how do you carry it out?

A

to make sure data is valid - making sure our result isn’t bias

  1. lay out two tape measures at right angles to make a 10m by 10m set of axes
  2. generate pairs of random numbers between 0-10 to make coordinates
  3. use coordinates to place quadrat
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11
Q

what is the con of quadrat sampling?

A

habitats are not uniform as there will be differences in abiotic conditions, this can affect the distribution of population

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12
Q

what is a community?

A

the population of all species present in an ecosystem at a particular time

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13
Q

how do species interact in a community?

A

feeding, recyling nutrients
competition for resorces
using abiotic resorces

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14
Q

what does an arrow mean in a food chain?

A

eaten by
shows direction that the energy and biomass moves

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15
Q

what are the stages of a food chain/web called?

A

trophic levels

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16
Q

what’s the first organism in a food chain called?

A

producer

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17
Q

what is the first animal in a food chain/web called?

A

primary consumer

18
Q

what is the second animal in a food chain/web called?

A

secondary consumer

19
Q

whats after the secondary consumer in a food web/chain?

A

tertiary consumer

20
Q

what is very useful about food webs?

A

they show the links between species in a community

21
Q

what are pyramids of number?

A

show the number of each organism in an ecosystem
can be odd shapes

22
Q

what are pyramids of biomass?

A

drawn to show the total mass of organisms in each trophic level
more accurate way of looking at the relative amounts of organisms

23
Q

what’s the unit for the food we eat?

A

kilojoules

24
Q

how do we express the energy available at a trophic level?

A

kilojoules per square meter per year

25
Q

does the energy fluctuate between trophic levels?

A

yes it should decrease in energy between each trophic level

26
Q

which is the least efficient transfer within food webs/chains?

A

light energy to produces
some light will miss the plant
some light is reflected off the cuticle
some light has the wrong wavelength and not absorbed by chlorophyll

27
Q

why is only 10% of energy passed from one trophic level to another?

A
  • some parts of the organism is not eaten
  • some parts are not digested and absorbed
  • they are egested as faeces
  • some materials are respired (for muscle contraction, body temperature etc)
28
Q

what are bacteria and fungi called in the nitrogen cycle and why?

A

called decomposers because they break down the dead remains and release chemicals for plants to use again

29
Q

what is nitrogen fixation?

A

when nitrogen gas is converted into ammonia
when nitrogen fixing bacteria in the soil and roots of legume plants absorb nitrogen and reduce it to make ammonia

30
Q

what is nitrification?

A

when ammonia is converted to nitrates by nitrifying bacteria and nitites

31
Q

what can plant food only do in the nitrogen cycle?

A

plant roots can only absorb the nitrates
combined with carbohydrates to form amino acids which are made into proteins, and DNA & RNA

32
Q

what’s assimilation?

A

animals eat plants
they digest proteins and DNA
used by animals to synthesise new proteins and DNA

33
Q

what’s decompostion?

A

when a plant or animal dies and its tissues are decomposed by bacteria and fungi

34
Q

what’s denitrification?

A

when nitrates are converted into nitrogen gas by denitrifying bacteria

35
Q

give some examples of legume plants:

A

peas, beans, clovers

36
Q

why are leguminous plants used on farms?

A

as they make the soil much more fertile

37
Q

carbon cycle:
when plants photosynthesis carbon atoms from carbon dioxide become part of glucose molecules in plant, what will happen to this carbon?

A
  • respiration = some of the glucose will be broken down via respiration and will become carbon dioxide again therefore released back into the air
  • eaten = the animals respire, release some of it back into the air as carbon dioxide
  • decomposers = when animal/plant dies decomposers will feed on them and the carbon becomes part of decomposers bodies therefore when they respire they release carbon dioxide into the air again
  • locking in = when living things don’t fully decay therefore fossil fuels are formed
  • combustion = when fossil fuels are burnt carbon is released into atmosphere
38
Q

what human activity acts as a source of CO2?

A
  • burning fossil fuels
  • slash and burn forest clearance
39
Q

what human activity acts as a source of methane?

A
  • generate by bacteria in anaerobic conditions
40
Q

what human activity acts as a source of methane?

A
  • burning fossil fuels
41
Q

potential effects of global warming:

A
  • melting of polar ice caps = sea levels rise = flooding
  • destruction of habitats = extinction of species
  • drought and desertification
  • increased extreme weather events
  • spread of disease
  • change in crops
  • increase in heat related illness and death