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Biology > Ecosystems > Flashcards

Ecosystems Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

whats an ecosystem

A

all the organisms living in a particular area and all the non-living (abiotic) conditions found there

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2
Q

whats a habitat

A

a place where an organism lives

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3
Q

whats biomass

A

the mass of living material in an organism

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4
Q

whats a producer

A

an organism that produces organic molecules using sunlight energy (plants)

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5
Q

what a consumer

A

an organism that eats other oganisms

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6
Q

whats a trophic level

A

a stage in a food chain thats occupied by a particular group of organisms

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7
Q

what are decomposers

A

an organism that breaks down dead or undigested organic material

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8
Q

some of the available energy (60%) is never taken in by organisms for what 4 reasons

A
  • plants cant use all the light energy that reaches therir leaves, e.g. wrong wavelength
  • some sunlight hits parts of plant that cant photosynthesise
  • some parts of food, e.g.bones and roots, arent eaten by organisms so energy isnt taken in
  • some parts of food are indigestable so pass through organisms and come out as waste
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9
Q

the available energy (40%) thats taken in is called what

A

gross productivity

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10
Q

whats gross productivity

A

energy available to organisms that is absorbed by them

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11
Q

whats respiration loss

A

the amount of energy lost to the environment when organisms use energy produced from respiration for movement or body heat

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12
Q

what % of total energy available and gross productivity becomes biomass, e.g. is stored or used for growth

A

10% of total energy available

25% of gross productivity

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13
Q

whats net productivity

A

the amount of energy thats available to the next trophic level in a food chain.

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14
Q

How is net productivity calculated

A

gross productivity - respiratory loss

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15
Q

How would you find out the efficieny of energy transfer between 2 trophic levels

A

work out percentage efficiency of energy transfer

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16
Q

how do you calculate % efficiency of energy transfer

A

(net productivity of trophic level/net productivity of previous trophic level) x100

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17
Q

As you move up a food chain, energy transfer generally becomes more/less efficient

A

more

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18
Q

Energy is lost at each trophic level, so more stages in a food chain, the more energy is lost overall. This energy loss does what

A

limits the number of organisms that can exist in a particular ecosystem

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19
Q

whats the efficiency of energy transfer from sun to producer

A

2-3%

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20
Q

whats the efficiency of energy transfer from producer to consumer

A

5-10%

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21
Q

whats the efficiency of energy transfer from consumer to consumer

A

15-20%

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22
Q

why is the efficiency of energy transfer from sun to producers the lowest

A

Not all the light energy that plants receive can be absorbed and some energy that is absorbed is then lost during photosynthesis

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23
Q

why is the efficiency of energy transfer from producer to consumer (5-10%) less efficient than consumer to consumer

A

plants contain greater proportion of indigestible material (cellulose within plant cell walls).

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24
Q

why is the efficiency of energy transfer from consumer to consumer (15-20%) more efficient than producer to consumer

A

animals contain a large proportion of relatively digestible meat, compared to plants (cellulose indigestible)

25
Q

How do you measure the efficiency of energy transfer. 3 steps

A
  • dry out organism, heat to 80°C until all water evaporates
  • weigh organism (dry mass), energy stored as biomass
  • multiply results from sample to estimate energy of one trophic level
26
Q

name 6 ways farming methods used to make transfer of energy between trophic levels more efficient

A 
herbicides
fungicides
insecticides
natural predators
fertilisers rearing livestock intensively
27
Q

what are the benefits of farming methods used to increase transfer of energy between trophic levels

A

more food can be produced in a shorter space of time, often at a lower cost

28
Q

what are some of the issues with farming methods used to increase transfer of energy between trophic levels

A

enhancing productivity by intensive rearing raises ethical issues. can cause animals pain, distress or restrict their natural behaviour.

29
Q

whats the carbon cycle

A

the movement of carbon through living organisms and the non-living environment

30
Q

whats saprobiontic nutrition

A

process of feeding on on dead organic matter used by decomposers

31
Q

whats photosynthesis’s role in the carbon cycle

A

CO2 in air/water absorbed by plants to carry out photosynthesis, becomes carbon compounds in plant tissues. Carbon passed to primary consumers, then to secondary and tertiary.

32
Q

whats decomposition’s role in the carbon cycle

A

all organisms are broken down decomposers(microorganisms). Secrete enzymes that break down carbon compounds. Absorb products for use in respiration (saprobiontic nutrition).

33
Q

whats respirations role in the carbon cycle

A

carbon is returned to the air (and water) as living organisms carry out respiration, which produces CO2

34
Q

whats combustions role in the carbon cycle

A

if dead organic matter ends up somewhere where there aren’t decomposers e.g. deep oceans, bogs, its carbon compounds can be turned into fossil fuels over millions of years (by heat and pressure). The carbon in fossil fuels is released when burnt (combustion)

35
Q

whats volcanoes role in the carbon cycle

A

Other types of rock form from dead organic matter deposited on the sea floor e.g. limestone, chalk. These rocks are drawn deep into earths crust by movement of tectonic plates . There they undergo chemical changes and release CO2, which is returned to the atmosphere by volcanoes.

36
Q

whats weathering’s role in the carbon cycle

A

rocks can also become land which is weathered(broken down by exposure to atmosphere). This can happen chemically by rainwater and physically. Chemical weathering causes mineral ions and bicarbonate ions to be released from the rock into solution and enter groundwater, from where they are transported into rivers and oceans. There they combine to form carbon-containing compounds.

37
Q

whats releases from and absorption into the ocean’s role in the carbon cycle

A

CO2 can also dissolve directly into the oceans from the atmosphere and be transported in the ocean by deep underwater currents.
CO2 can remain in these slow-moving currents for hundreds of years before returning to the surface and being released back into the atmosphere.

38
Q

whats the nitrogen cycle

A

the conversion of nitrogen into a usable form and its movement through living organisms and the non-living environment.

39
Q

whats nitrogen fixation

A

the process which nitrogen gas in the atmosphere is turned into ammonia by bacteria such as Rhizobium and Azotobacter

40
Q

whats ammonification

A

the process in which nitrogen compounds from dead organisms or waste material are turned into ammonia by decomposers. This ammonia then goes on to form ammonium ions.

41
Q

whats nitrification

A

the process in which ammonium ions in the soil are changed into nitrogen compounds by nitrifying bacteria called Nitrosomonas and Nitrobacter.

42
Q

whats denitrification

A

the process in which nitrates in the soil are converted into nitrogen gas by denitrifying bacteria

43
Q

what are the 4 processes in the nitrogen cycle in order

A

1) nitrogen fixation
2) ammonification (by decomposers)
3) nitrification
4) denitrification

44
Q

Where is Rhizobium found

A

inside root nodules of leguminous plants (beans, peas, clovers)

45
Q

What does Rhizobium do

A

forms mutualistic relationship with plants, provide plant with nitrogen compounds and plant provides them with carbohydrates.

46
Q

where is Azotobacter found

A

in living soil. Don’t form mutualistic relationships with plants.

47
Q

name 2 other ways for nitrogen to enter an ecosystem other than the nitrogen cycle

A
  • lighting (also fixes atmospheric nitrogen)

- artificial fertilisers (produced from atmospheric nitrogen in haber process)

48
Q

whats sucession

A

the process by which an ecosystem changes over time

49
Q

whats primary succession

A

succession which happens on newly formed or exposed land with no soil.

50
Q

whats secondary succession

A

succession which happens on land cleared of all plants but where the soil remains, e.g. after a forest fire

51
Q

what’s considered the the dominant species in an ecosystem

A

the species that causes the most change to the abiotic environment

52
Q

what climax community

A

the largest and most complex community of plants and animals an ecosystem can support

53
Q

whats abundance when investigating ecosystems

A

number of individuals of one species in a particular area

54
Q

name the 2 ways of meauring abundance of motile organisms and plants

A
  • simply by counting the number of individuals in a sample taken
  • percentage cover can also be used for plants
55
Q

whats distribution when investigating ecosystems

A

where a particular species is within an area being investigated

56
Q

name 2 methods of sampling that could be used for non-motile or slow organisms

A

quadrats

transects

57
Q

name 2 types of quadrat

A

frame

point

58
Q

name 3 types of transect

A

line transect
belt transect
interrupted transects

Biology (10 decks)

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