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Biology 2 > B7 Ecology > Flashcards

B7 Ecology Flashcards

1
Q

Explain how abiotic and biotic factors can cause an uneven dispersal of plants

A

Abiotic: lack of light in certain areas like due to a tree means less photosynthesis so less glucose and less proteins meaning less growth. Trees may absorb more nutrients and water so less growth there for other plants
Biotic: More insects in certain areas meaning more plants are eaten there so less plants

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2
Q

How should the student decide where to place the quadrat and why?

A

Use a random number generator to generate random coordinates to achieve randomness

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3
Q

Describe how carbon is cycled through living organisms

A
  • Green plants absorb CO2 through the stomata for photosynthesis to make glucose for growth and storage as starch
  • Animals eat the green plants and so take in the CO2 to use the carbon compound to make other carbon compounds
  • CO2 is released during respiration in animals (but also plants)
  • When animals die they release CO2 as they are decayed by microorganisms thet respire and release CO2 into the atmosphere
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4
Q

Give 5 abiotic factors

A
  • light intensity
  • temperature
  • oxygen levels
  • carbon dioxide levels
  • mineral ion levels
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5
Q

What three factors do plants compete for?

A
  • light
  • water
  • space
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6
Q

How can you use a quadrat to make valid conclusions?

A

Repeat at different random locations

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7
Q

Why has deforestation increased? (2)

A
  • provide land for cattle for agriculture
  • grow crops for biofuels to provide fuel
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8
Q

Why does total biomass decrease along the food chain? (3)

A
  • lost in faeces - egested so not all absorbed
  • excreted in urine
  • used in respiration which releases CO2
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9
Q

Plan an investigation to estimate population size of a plant species

A
  • use of quadrat of area eg 1m×1m
  • quadrats are placed randomly using a random number generator to find random coordinates
  • count number of plants (in each quadrat)
  • repeat, using a large number of quadrats
  • calculate mean per quadrat
  • calculate area of field area of field (length × width)
  • population = total area/area sampled x species counted
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10
Q

Explain the advantage of making crops resistant to herbicides

A

Only weeds are killed but crops are not killed. This means there is less competition, like for light and water, so crops have a higher yield as can photosynthesise more.

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11
Q

What are 3 features organisms have to aid their survival?

A
  • structural
  • functional
  • behavioural
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12
Q

What are functional adaptations of animals in hot deserts?

A

Stay in cooler conditions/ sweat less so lose less water because little water is available in deserts, energy stores last longer

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13
Q

What is the purpose of a fat store?

A

Insulation
Energy store that can be metabolised

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14
Q

What is the purpose of a hard mouth?

A

Avoids damage when eating hard foods

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15
Q

Why is rate of decomposition slower in waterlogged compost heaps

A

Waterlogged means less oxygen for decomposers so less aerobic respiration meaning less energy so decomposers work less efficiently. This also means temperature may not be as warm so enzymes not working at optimal conditions.

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16
Q

Describe a peat bog

A

Acidic, waterlogged with low levels of oxygen that act as ‘carbon sinks’ (store carbon)

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17
Q

What is peat used for?

A
  • agriculture for cheap compost/fertilisers
  • burned for fuel
18
Q

Explain how draining peat bogs contributes to global warming

A

The draining of water allows air (and oxygen) to return to the soil
This allows microorganism to carry out aerobic respiration and decay the organic matter
This releases CO2 which is a greenhouse gas (especially because peat bogs are known as ‘carbon sinks’ that store carbon) and so contributes to global warming

19
Q

Give 4 ways humans have adapted to increase production of food

A
  • cleared land for agriculture - farming
  • using fertilisers
  • pesticides and herbicides
  • genetic modification
20
Q

A large amount of untreated sewage entered the river. Many fish died. Untreated sewage contains organic matter and bacteria.
Explain why many fish died

A
  • bacteria decay organic matter by digestion and bacteria respire aerobically
  • bacteria use up oxygen so lowers oxygen concentration, meaning fish have less oxygen
  • reduced energy supply causes death of fish
21
Q

Give two reasons why species counted with quadrat are not valid

A
  • quadrat too small/sample size too small - use more quadrats
  • not representative
22
Q

‘Light intensity affects the number of dandelion plants that grow in an area.’ Plan an investigation to test this hypothesis.

A
  • transect along an ecological gradient with different light intensities
  • use a large number of quadrats along transect at regular intervals, using continuous sampling
  • for each quadrat count number of dandelions and record
  • for each quadrat measure light intensity (with a light probe)
  • compare data from different light intensity
23
Q

How do microorganisms help cycle materials and how this benefits plants.

A
  • Break down large molecules to small molecules by secreting enzymes and respiration which releases carbon dioxide and energy for other processes such as active transport
  • Release mineral ions eg nitrate and magnesium ions
  • Plants take in carbon dioxide through diffusion by stomata for photosynthesis producing glucose required for growth which helps make amino acids
  • Plants take in ions through roots by active transport for amino acid and protein production and chlorophyll synthesis
24
Q

Why do micro-organisms decay faster in higher temperatures?

A

More energy so enzyme activity is higher, faster reactions

25
Q

How does more oxygen increase rate of decay?

A

More oxygen so more aerobic respiration of decomposers such as bacteria, releasing more energy so faster reactions

26
Q

Suggest how to sterilise equipment in a lab

A

Heating to over 100 degrees

27
Q

Explain what effect the changing concentration of carbon dioxide in the atmosphere could have on living organisms.

A
  • higher CO2 concentration can increase global warming
  • plants photosynthesise faster as more CO2
  • climate change results in polar ice caps melting leading to flooding resulting in loss of habitat so animals may become extinct, reducing biodiversity
28
Q

Describe how fishing quotas can help to return fish stocks to a sustainable level

A

Fewer fish caught/ less young fish caught so more fish survive and can reproduce

29
Q

Describe:
* why more land is being used for farming
* how increased farming has decreased biodiversity.

A
  • more land used: increased population increases demand for food so more crops and livestock for food, crops also for biofuels
  • reduces biodiversity as deforestation results in loss of habitats and losing hedgerows due to larger lands needed
  • more methane from cattle contributes to more global warming so polar ice caps melt leading to flooding and loss of habitat, further reducing biodiversity
30
Q

Give two possible effects of a rise in the Earth’s temperature.

A
  • climate change resulting in polar ice caps melting
  • flooding and sea levels rising result in loss of habitats, reducing biodiversity
31
Q

How does changes to farming for other animals food can improve human food security

A
  • less land could be needed
  • more food and space for humans to grow crops
  • less methane from animals so less global warming
  • less harmful effects of global warming on human food production, such as flooding farm land
32
Q

Evaluate use of fishing quotas and changing net sizes on fish survival

A
  • less younger fish caught so survive and can reproduce, increasing biomass
  • other factors could impact fish survival
  • quotas lead to dead fish being thrown in the sea
33
Q

Why are fermentors sterilised?

A

To kill existing microorganisms that could kill fungus/fusarium

34
Q

How does intensive farming improve farming efficiency? (2)

A
  • warmer indoors so less energy wasted in keeping warm
  • less movement indoors as in an enclosed environment so less energy wasted for movement
35
Q

Give 3 reasons why humans may oppose the use of intensive farming

A
  • diseases can rapidly spread
  • antibiotics may be overused - antibiotic meat
  • ethical issues, seen as cruel and harmful to animals which can stress animals, reducing productivity
36
Q

Explain how the intensive farming of pigs increases the efficiency of food production

A
  • kept inside in a temperature controlled environment so less heat energy is lost in controlling body temperature
  • kept enclosed or in a restricted environment so less energy required for movement
  • less energy / heat is transferred to the environment
  • so more energy is available for growth
37
Q

Explain how mycoprotein formed

A
  • fungus/fusarium
  • in fermentor with glucose and in presence of oxygen (aerobic conditions)
  • aerobically respires, releasing energy and waste goes out
  • mycoprotein harvested and purified
38
Q

Give 3 examples of water pollutants

A
  • herbicides and fungicides
  • organic matter
  • fertiliser
39
Q

Explain the effects of air pollution and water pollution

A
  • global warming -> climate change means ice caps melt and flooding so may lead to loss of habitat and so migration of species eg diseases
  • soot means less light as its blocked so less photosynthesis so less glucose for growth
  • soot also causes respiratory problems in humans (to do with breathing)
  • sewage means bacteria multiply, use more oxygen for respiration so aquatic animals have less oxygen so can’t respire and die
40
Q

What are 3 uses of water?

A
  • photosynthesis
  • transport/transpiration stream
  • support

Biology 2 (3 decks)

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