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Biology > Ecology and the Environment > Flashcards

Ecology and the Environment Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

population

A

all individuals of one species at one place at one time. E.g. all magpies in my garden at one time

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2
Q

community

A

all populations at one place at one time. E.g. every living organism (animals, plants) in my garden at one time

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3
Q

habitat

A

the places where a specific organism lives (whales - the ocean)

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4
Q

ecosystem

A

as all the biotic factors and all the abiotic factors that interact within an area at one time (eg a garden pond)

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5
Q

species

A

one type of creature (eg hoeosapions)

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6
Q

4.2 - practical investigate the population size of an organism in 2 different areas using quadrats

A
  1. use 2 tape measures to lay out a survey area (eg 10m x 10m)
  2. use a random number generator to create a set of coordinates to place the quadrat
  3. count the number of chosen species within the quadrat
  4. repeat steps 2-3 10x
  5. estimate the number of species in entire area with the formula:
    find mean species per quadrat x total area of survey area

repeat entire process in a different area

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7
Q

whats a quadrat

A

Quadrats are square frames made of wood or wire
They can be a variety of sizes eg. 0.25m2 or 1m2
They are placed on the ground and the organisms within them are recorded

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8
Q

what can quadrats measure

A

The number of an individual species: the total number of individuals of a single species (eg. buttercups) is recorded

Species richness: the total number of different species (but not the number of individuals of each species) is recorded

Percentage cover: the approximate percentage of the quadrat area in which an individual species is found is recorded (this method is used when it is difficult to count individuals of the plant species being recorded eg. grass or moss

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9
Q

biotic factors

A

living

Competition
Predator-prey relationships
Interactions with other organisms within the food chain or food web

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10
Q

abiotic factors

A

non-living

Light intensity
Mineral availability
Water availability
pH
Temperature

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11
Q

what does biodiversity mean

A

the range and variety of different species of organisms on Earth, or within an ecosystem

It considers not only the species richness but the variation within each species, its distribution and population size

E.g. a high biodiversity would be found in an environment with lots of different species which show a lot of variation and are living in, all evenly distributed across the study area

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12
Q

4.4B practical - investigate the distribution of organisms in their habitats and measure biodiversity using quadrats

A
  1. Use 2 tape measures to lay out your first survey area (e.g. 10m X 10m)
  2. Use a random number generator to create a set of coordinates to place your first quadrat
  3. Count the number of different species and the number of each species found within that quadrat
  4. Repeat this process until you have collected the data for 10 quadrats
  5. Repeat these steps for the second survey area

the area with the greatest number of different species and the number of each species

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13
Q

species evenness

A

total number of organisms of each species in a place

for example if there was 2 oak trees, 2 spruce trees and 2 birch trees in one place and
4 oak trees, 1 spruce tree and 1 birch tree in another place

the first place would have the good evenness

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14
Q

species richness

A

the number of different species present in a place

eg. oak, spruce, birch, jungle = 4

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15
Q

how does light intensity affect communities

A

abiotic

light is needed to photosynthesis. more light leads to an increase in photosynthesis rate and an increase in plant growth

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16
Q

how does temperature affect communities

A

abiotic

affects photosynthesis rate in plants and therefore growth in plants

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17
Q

how does moisture levels affect communities

A

abiotic

plants and animals require water to survive

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18
Q

how does soil pH and mineral content affect communities

A

abiotic

less mineral ions will negatively affect plants as they won’t be able to osmosis as well

changing pH affects plants as they are adapted for certain conditions

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19
Q

how does CO2 levels affect communities

A

abiotic

CO2 is required for photosynthesis so CO2 conc affects photosynthesis rate

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20
Q

how does O2 levels affect aquatic animals

A

abiotic

affects aquatic animals as they can only survive in water with high O2 conc

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21
Q

availability of food

A

biotic

more food means organisms have a higher chance of survival and reproducing. this means the population will increase

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22
Q

new predators

A

biotic

in balanced ecosystems predators catch enough prey to survive but not enough to wipe out the population. if a new predator is introduced then it could unbalance the ecosystem

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23
Q

new pathogens

A

biotic

if a new pathogen enters an ecosystem the populations living their will no longer have immunity which will put the populations in decline

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24
Q

competition

A

biotic

if 2 species compete for the same resources and one is better equipped to to take advantage of the food, the better equipped one will get the resources meaning the other species will decline

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25
Q

producer

A

they produce their own energy

eg plants photosynthesing

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26
Q

primary consumer

A

the organisms which eat the producer

eg sheep who eat the grass

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27
Q

tertiary consumer

A

feed on the secondary consumer

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28
Q

secondary consumer

A

feed on the primary consumer

29
Q

what is a trophic level

A

a different stage of a food chain

eg one trophic level might be the primary consumers

30
Q

decomposer

A

organisms (bacteria and fungi) which secrete digestive enzymes to decay dead organic matter to obtain their food, these help recycle nutrients

31
Q

what does a food chain show

A

a simple way to show the feeding interactions between organisms in a community

the arrows show the direction that the energy is travelling in

32
Q

what does a food web show

A

shows a more complex version and accurate version of the feeding interactions between the organisms in a community
can also show interdependence (how the change in one population can affect others)

33
Q

what does a pyramid of number show

A

A pyramid of numbers shows how many organisms at each level of a food chain.

You cannot change the trophic level of the organisms - they must stay in the same order as in the food chain with producers on the bottom, followed by primary consumers, then secondary consumers, then tertiary consumers
this is why the pyramid of number is slightly flawed

the pyramids always has the first thing on the food chain at the bottom and then the second and etc

34
Q

what does a pyramid of biomass show

A

shows 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

these are always more like a normal pyramid
This is because the mass of organisms has to decrease as you go up a food chain – if we take our first food chain as an example, it’s impossible to have 10kg of grass-feeding 50kg of voles feeding 100kg of barn owls

35
Q

what does a pyramid of energy transfer show

A

Pyramids of energy illustrate the amount of energy contained within the biomass of individuals within different trophic levels

The area of each box represents the quantity of energy present

These pyramids always have a wide base (due to the large amount of energy contained within the biomass of producers)

As you move up the pyramid to higher trophic levels the quantity of energy decreases as not all energy is transferred to the biomass of the next trophic level (roughly only 10 % of the energy is passed on)

36
Q

how does the transfer of energy and substances work in a food chain

A

Energy flows from the sun to the first trophic level (producers) in the form of light
Producers convert light energy into chemical energy
This occurs during photosynthesis, when producers convert carbon dioxide and water into glucose and oxygen
Producers use this glucose (during respiration) to produce their own biomass
When primary consumers consume (eat) producers, they break down the biomass of the producer (digestion) and use the chemical energy to increase or sustain their own biomass
When secondary consumers consume (eat) primary consumers, they break down the biomass of the primary consumer (digestion) and use the chemical energy to increase or sustain their own biomass, and so on
In this way, as chemical energy is transferred from one trophic level to the next, biomass is also transferred

37
Q

what is biomass

A

Biomass is a store of chemical energy

38
Q

how much energy is lost between each trophic level

A

ruffly 90% is lost between each trophic level

39
Q

why do food chains rarely contain more than 6 trophic levels

A

the total amount of energy available eventually becomes too small to support another trophic level as 90% is lost between each level

40
Q

how is energy lost at each trophic level

A

Organisms rarely eat every part of the organism they are consuming – some of the biological material of plants and animals may be inedible

Not all the ingested material is digested and absorbed, some is egested as faeces

Energy is used for movement

Energy is used to generate heat

Energy is used for metabolic processes

Some absorbed material is lost as waste:
Carbon dioxide and water are waste products of respiration
Water and urea are the waste products in the urine, which is produced when proteins are broken down

41
Q

what is the role of the nitrogen fixing bacteria

A

takes N2 gas and change it into nitrates in the soil

42
Q

what is the role of decomposers

A

When the animals and plants die, they decay and all the proteins inside them are broken down into ammonium compounds and put back into the soil

43
Q

what is the role of nitrifying bacteria

A

convert the ammonium compounds (from the decomposers) to nitrites and then to nitrates

44
Q

what is the role of denitrifying bacteria

A

take the nitrates out of the soil and convert them back into N2 gas

45
Q

why can’t animals and plants absorb nitrogen out of the air

A

N2 gas is very stable and the bonds holding the nitrogen atoms together would need massive amounts of energy to break (the two nitrogen atoms in a nitrogen molecule are held together by a triple covalent bond)

46
Q

why do we need nitrogen

A

Nitrogen as an element is required to make proteins

47
Q

what is nitrogen fixing

A

nitrogen taken out of the air and converted into something easier to absorb such as nitrates

48
Q

what nitrogen fixes

A

lightning

nitrogen fixing bacteria

49
Q

how does lighting nitrogen fix

A

splitting the bond between the two atoms and turning them into nitrous oxides like N2O and NO2 that dissolve in rainwater and ‘leach’ into the soil

50
Q

how does the fixed nitrogen get removed from the soil

A

denitrification (bad denitrifying bacteria)

plants actively transport N ions into their roots

51
Q

how does nitrogen get put into the soil

A

nitrogen fixing (lighting or nitrogen fixing bacteria)

nitrification (nitrifying bacteria)

52
Q

how do animals get nitrogen

A

eat the plants (or other animals) which contain amino acids and proteins

53
Q

how do plants get nitrogen

A

plants actively transport N ions into their roots

54
Q

how do animals get rid of the nitrogen

A

waste (urine and faeces) which puts the nitrogen back into the soil as ammonium compounds

55
Q

how does denitrifying bacteria work

A

they are found in poorly aerated soil which mean they respire anaerobically which puts the nitrogen straight out of the soil and into the air again

56
Q

how to prevent denitrifying bacteria

A

by ploughing and turning over soil (aerating)

57
Q

how is carbon put into the soil

A

decaying waste
fossilisation of dead plants and animals occurs in specific conditions

58
Q

how is carbon taken out of the soil

A

carbon in dead and decaying matter is broken down by decomposers
carbon stored in fossil fuels is extracted

59
Q

how is carbon put into the atmosphere

A

carbon is released when fossil fuels are burned in factories or cars or planes (combustion)
carbon is released during respiration of plants, animals and decomposers
plants are eaten by animals which then respire as well

60
Q

how is carbon taken out of the atmosphere

A

photosynthesis from plants

61
Q

biological consequences of pollution of air by sulfer dioxide

A

acid rain can damage plants and animals and also make rivers + lakes acidic damaging aquatic organisms.
can also cause leaching of toxic minerals into lakes

62
Q

what are the greenhouse gases

A

Water vapour
Carbon dioxide
Methane
Nitrous oxides
CFCs - Chlorofluorocarbons

63
Q

biological consequences of pollution of air by carbon monoxide

A

CO binds irreversibly to hemoglobin in red blood cells forming (carboxyhaemoglobin), preventing them from carrying oxygen to vital organs like the heart and brain

63
Q

how does an increase in greenhouse gases result in an enhanced greenhouse effect

A

The Sun emits rays that enter the Earth’s atmosphere
The heat bounces back from the Earth’s surface
Some heat is reflected back out into space
Some heat is absorbed by greenhouse gases and is trapped within the Earth’s atmosphere – this is normal
However, as the levels of greenhouse gases in the atmosphere rise due to human activities the atmosphere gets thicker and traps more heat causing the earth to heat up more than usual making it the enhanced greenhouse effect

63
Q

how have human activities contributed to greenhouse gases

A

Carbon dioxide is produced during the combustion of fossil fuel
Methane is produced by cattle as they digest grass and released by rice paddy fields
Deforestation: Clearing forests reduces the Earth’s capacity to absorb CO₂ through photosynthesis

64
Q

consequences of global warming

A

Ocean temperatures increasing, causing melting of polar ice caps / rising sea levels / flooding / coral bleaching
Increasing temperatures causing extreme weather like super storms, flooding, droughts
Changes in or loss of habitats due to these extreme weather events
Decreases in biodiversity as food chains are disrupted and extinction rates increase
Increases in migration of species to new places, including increased spread of pests and disease

65
Q

what are the biological consequences of pollution of water by sewage

A

toxic chemicals can’t be broken down and so build up and bioaccumulation and may even build up to toxic levels (biomagnifacation)

untreated sewage - sewage provides a good source of food for decomposers which therefore breed and with more they use up oxygen in the water when respiring aerobically. This lack of oxygen in the water causes death of other aquatic organisms as they don’t have enough oxygen. The death of these organisms causes more food for decomposers and the process repeats. (eutrphacation)

66
Q

what are the biological consequences of eutrophication caused by leached minerals from fertiliser

A

fertilisers - cause increase in growth in aquatic plants meaning less light reaches the bottom of the water so plants die when provides more food for the decomposers which therefore breed and with more they use up oxygen in the water when respiring aerobically. This lack of oxygen in the water causes death of other aquatic organisms as they don’t have enough oxygen. The death of these organisms causes more food for decomposers and the process repeats. (eutrphacation)

67
Q

effects of deforestation

A

leaching - if there is deforestation then there are less trees to uptake water so the water runs off into lakes and rivers. This means the mineral ions are removed from the soil and some of these nutrients (especially nitrates), can lead to further problems such as eutrophication

soil erosion - The water running off from deforested areas may carry away some of the topsoil, causing erosion. Because of deforestation there are no plants present in the soil and therefore there are no roots holding the soil in place. The topsoil contains the most fertile, mineral ion rich materials: when it is lost due to erosion the minerals are also lost, making the land very difficult to use for crop growth and reducing the chance of plants re-growing.

evapotranspiration - water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants. Transpiration is the evaporation and diffusion of water through the stomata of leaves. This evaporated water moves into the atmosphere and eventually (through the water cycle) makes rain in rain clouds. These rain clouds when then rain onto the plants, and the cycle will continue. When deforestation occurs, this cycle is broken.

carbon cycle - trees photosynthesis and so when you cut them down they can’t meaning that less carbon dioxide gets converted back into oxygen breaking the cycle. The cut down trees are usually burnt aswell which adds more carbon back into the atmosphere

imbalance of atmospheric gases - more CO2 in atmosphere and less O2 as trees don’t photosynthesis as they are cut down

Biology (7 decks)

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