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Biology - all note flashcards > Environmental interactions - 4th form > Flashcards

Environmental interactions - 4th form Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what is ecology

A

the study of ecosystems

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2
Q

what is an ecosystem

A

a system or area where organisms interact with their physical environment

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3
Q

what components do all ecosystems include

A

producers
consumers
decomposers
physical environment
range of different habitats

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4
Q

what are producers

A

organisms which make their own food (such as photosynthesising plants)

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5
Q

what are consumers

A

organisms which eat other living things (such as animals)

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6
Q

what are decomposers

A

organisms which secrete digestive enzymes to decay (breakdown) dead organic matter to obtain their food; they help to recycle nutrients

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7
Q

what is a physical environment

A

all the non-living (abiotic) factors which affect growth and survival of living things

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8
Q

what are examples of abiotic factors in a physical environment

A

temperature
carbon dioxide
oxygen contractions
minerals in the soil

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9
Q

what are habitats

A

places where specific organisms live

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10
Q

what could different habitats include in a pond

A

shallow water
deep water
soil
centre of a clump of pondweed

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11
Q

what is a population

A

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

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12
Q

what piece of equipment may ecologists use to measure the size of a population in a habitat

A

a quadrat
—— most of the time we use a 50cm x 50cm square; the area is 0.25m^2

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13
Q

what would you do to find out the population of a species in a habitat

A

1- calculate the area of the habitat
2- measure the number of individuals in one quadrat and repeat many times to check our result is reliable (at least 10 are needed)
3- calculate the average number of individuals in a quadrat
4- calculate how many quadrats fit in a total area
5- multiply the result from step 4 by the result from step 3

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14
Q

why do we use random sampling

A

to make sure our data is valid as it means we are avoiding choosing areas which may be interesting as it would bias our result

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15
Q

how do you take a random sample

A

1- lay out two tape measures at right angles to make a 10m by 10m set of axes. generate pairs of random numbers between 0 and 10 - these are coordinates
2- use the coordinates to place your quadrat

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16
Q

why are habitats not uniform

A

there will be differences in abiotic conditions such as light intensity or one area may be trampled - these differences could affect the distribution of our population

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17
Q

how can we investigate that habitats are not uniform

A

1- pick two contrasting areas and set up a grid in each. use random sampling to take repeated measurements with a quadrat and compare the average results

2- use a transect which is a line across the habitat, which is placed to pass through a range of abiotic conditions (such as from light to shade, across a path) a quadrat is placed at regular intervals along the transect and used to measure the number or % cover of the species

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18
Q

what is a transect

A

a line across the habitat, which is placed to pass through a range of abiotic conditions

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19
Q

what is a biotic factor

A

living factor

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20
Q

what is an abiotic factor

A

non-living

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21
Q

what is a community

A

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

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22
Q

how are species in a community and physical environment interacting with each other

A
  • feeding on each other - this allows nutrients to be recycles
  • competition for resources (such as food, mates, nesting sites, light, mineral ions)
  • using abiotic resources (such as absorbing mineral ions from the soil and using water
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23
Q

how can we show feeding relationships in an ecosystem

A

using food chains

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24
Q

what do the arrows in food chains mean

A

is eaten by - they show the direction that energy and biomass moves, from the species that is eaten to the animal that eats it

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25
Q

what are trophic levels

A

the stages in a food chain (or web)

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26
Q

what do we label the organisms in a food chain or web

A

producers
consumers

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27
Q

what is the first, second and third animal called in a food chain/web

A

first = primary consumer
second = secondary consumer
third = tertiary consumer

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28
Q

what are decomposers needed for

A

they are vital for recycling nutrients

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29
Q

why are food webs useful

A

it is particularly useful for understanding the links between the species in a community

30
Q

what can we use ecological pyramids for

A

to represent the relative amounts of organisms at each trophic level - they are always drawn to scale

31
Q

what are pyramids of number

A

these are drawn to show the number of each organism counted in the ecosystem. they can be odd shapes due to the different masses of organisms

32
Q

what are pyramids of biomass

A

these are drawn to show the total mass of the organisms in each trophic level (i.e the mass of an individual x the number of individuals). these are a more accurate way of looking at the relative amounts of organisms

33
Q

what are the units for energy we eat

A

kilojoules

34
Q

how do biologists express the energy available at a trophic level in a particular area

A

kilojoules per square metre per year - kJ/m^2/ year

35
Q

what are pyramids of energy

A

these are drawn to show the total energy available in each trophic level per square metre per year. there should be a decrease in energy between each trophic level

36
Q

what is the least efficient energy transfer

A

from light energy to the producer

37
Q

why is the least efficient energy transfer from light to the producer

A
  • some light will miss the plant or the plants chloroplast
  • some light will be reflected by the cuticle
  • some light has the wrong wavelength to be absorbed by the chlorophyll
38
Q

roughly how much energy is passed from one trophic level to the next

A

approximately 10%

39
Q

why is only around 10% of energy transferred between trophic levels

A

-some parts of the organisms are not eaten (so the biological molecules are not available are not available for respiration)
- some parts are not digested and absorbed - they are egested as faeces (so the biological molecules are not available are not available for respiration)
- some materials are respired to release energy - the energy is used for:
– muscle contraction (such as movement and breathing)
– maintaining a constant body temperature (in mammals and bird)
– synthesising biological molecules (including excretory products)
– movement of molecules (active transport)
– cell division

40
Q

what happens when plants photosynthesise

A

carbon atoms from carbon dioxide become part of glucose molecules (which is stored as starch) in the plant

41
Q

what happens to the carbon in the glucose molecules when plants have photosynthesised

A

a) some of the glucose will be broken down by the plant in respiration. the carbon in the glucose becomes part of the carbon dioxide molecule again, and is released back into the air
b) some of the carbon compounds in the plant will be eaten by animals. the animals respire, releasing some of it back into the air as carbon dioxide
c) when the plant or animal dies, decomposers (bacteria and fungi) will feed on them. the carbon becomes part of the decomposers’ bodies. when they respire they release carbon dioxide into the air again
d) fossilation occurs when living things do not decay fully when they die due to the to the conditions in the soil. fossil fuels are then formed over millions of years by a process called ‘locking in’. these include coal, oil, natural gas and peat.
e) when fossils fuels are burnt (combustion), carbon dioxide is released into the atmosphere

42
Q

what are the bacteria and fungi in the soil called and why

A

decomposers - they break down the dead remains and release the chemicals and release the chemicals for the plants plants to use again. feeding assimilation pass nitrogen - for example in protein molecules - along food chains

43
Q

explain the steps of the nitrogen cycle

A

1- nitrogenfixing bacteria in the soil and the roots of legume plants absorb nitrogen and reduce it to make ammonia - this is called nitrogen fixation
2- the ammonia is converted to nitrites and nitrates by the nitrifying bacteria - this is called nitrification
3- plant roots can only absorb the nitrates. they are combined with carbohydrates (from photosynthesis) to form amino acids which are then made into proteins, and nucleotides which are joined to make DNA and RNA
4- animals eat plants. they digest the proteins and DNA, absorbing the small soluble molecules (amino acids and nucleotides). these are used by the animal to synthesise (make) new proteins and DNA (assimilation)
5- when a plant or animal dies its tissues are decomposed by bacteria and fungi (saprotrophic feeding)
6- molecules containing nitrogen such as proteins are broken down by the bacteria and fungi and ammonia is released into the soil
7- some nitrates are converted into N2 by denitrifying bacteria - this process is called denitrification

44
Q

what is decomposition

A

protein in dead plants and animals is broken down
ammonia is released into the soil

45
Q

what bacteria is involved in decomposition

A

decomposing bacteria

46
Q

what is nitrification

A

ammonia is converted to nitrites, and nitrites are converted into nitrates

47
Q

what bacteria is involved in nitrification

A

nitrifying bacteria

48
Q

what is denitrification

A

nitrates are converted to nitrogen gas
(denitrification reduces the amount of nitrate in the soil and therefore makes the soil less fertile)

49
Q

what bacteria is involved in denitrification

A

denitrifying bacteria

50
Q

what is nitrogen fixation

A

nitrogen gas is converted to ammonia in bacteria which is used to make proteins, when the bacteria die their proteins decompose, releasing ammonia back into the soil

51
Q

what bacteria is involved in nitrogen fixation

A

nitrogen-fixing bacteria found in soil and root nodules of plants

52
Q

where do some nitrogen fixing bacteria live

A

in small structures - nodules - on the roots of legume plants. this is a mutualistic relationship - the bacteria receive glucose from the plant, while the plant absorbs ammonia from bacteria in the middle

53
Q

what happens when nitrogen fixing bacteria decompose

A

they make the soil much more fertile by releasing ammonia which can be converted into nitrates. this is why farmers may rotate the crops they grow in each field. they could grow clover but instead they often grow leguminous plants which they can then sell such as peas

54
Q

what does the sun emit

A

radiation which travels through space

55
Q

what happens to the radiation emitted by the sun

A

travels through space. some is reflected by the earth’s atmosphere, but some passes through and is absorbed by the earth’s surface - this warms the earth , which then emits infra-red (IR) radiation

56
Q

what happens to the IR radiation that the earth emits

A

some IR radiation passes through the atmosphere into space, but some gases in the atmosphere absorb the IR radiation, preventing it from escaping back into space. this leads to more energy being held by the atmosphere, heating it.

57
Q

which gases absorb the IR radiation, preventing it from escaping back into space

A

water vapour, carbon dioxide, methane, nitrous oxides and CFCs

58
Q

how is the greenhouse effect essential for life on earth

A

without it the entire planet would be frozen

59
Q

what is any extra greenhouse effect caused by human activity called

A

enhanced greenhouse effect

60
Q

what is the human activity which acts as a source for CO2

A

burning fossil fuels
slash and burn forest clearance

61
Q

what is the human activity which acts as a source for methane

A

generated by bacteria in anaerobic conditions such as:
– ruminants such as cattle produce large volumes of methane from the anaerobic activity of bacteria in their gut – this largely comes out from their mouths
– bacteria is waterlogged paddy fields for rice cultivation give off methane

62
Q

what is the human activity which acts as a source for nitrous oxides

A

burning fossil fuels

63
Q

what is the human activity which acts as a source for CFCs

A

until the 1990’s CFCs were used as a solvent for aerosols such as deodorants + they were also used in fridges and freezers
CFCs were also blamed for the hole in the ozone layer

64
Q

what are the potential effects of global warming

A

melting of polar ice caps
destruction of habitats
drought and desertification
increased extreme weather events
spread of disease
change in crops
increase in heat related illness and deaths

65
Q

explain the effect of melting polar ice caps

A

if ice shelves over land melt, such as over Greenland and Antarctica, this will lead to sea level rises, causing flooding in coastal regions worldwide

66
Q

explain the effect of destruction of habitats

A

for example grassland may turn to desert (desertification), leading to the loss of habitat for resident species - this could lead to the extinction of species

67
Q

explain the effect of drought and desertification

A

can lead to crop failure and therefore to food shortages and famines

68
Q

explain the effect of increased extreme weather events

A

extreme weather events such as hurricanes could become more frequent as there is more energy present in weather systems due to global warming

69
Q

explain the effect of spread of disease

A

as the planet warms it will be possible for disease carrying organisms, such as mosquitos, to survive in a wider range of countries. this means diseases such as malaria and dengue fever are likely to become more common

70
Q

explain the effect of change in crops

A

as areas warm it will become possible to grow different crops (e.g olives and grapes in southern England) - this will be beneficial to some countries

71
Q

explain the effect of increase in heart related illness and deaths

A

in recent years there have been increases in death rates in elderly associated with heat waves - this may become more common

Biology - all note flashcards (7 decks)

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