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Biology > 8 - Ecology and the Environment > Flashcards

8 - Ecology and the Environment Flashcards

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1
Q

What is a habitat?

A

The place where an organism lives

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2
Q

What is a population?

A

All the organisms of one species in a habitat

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3
Q

What is a community?

A

All of the different species in a habitat

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4
Q

What is an ecosystem?

A

All the organisms living in one particular area and all the non-living (abiotic) conditions

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5
Q

Describe how to estimate the population size using a quadrat

A
  • Place a 1m2 quadrat on the ground at a random point within the area you’re investigating
  • Count all the organisms in the quadrat
  • Multiply by the total area of the habitat
  • Repeat on another area to compare the population sizes
  • The sample may not be a representation of the population
  • The sample size affects the accuracy of the estimate (the bigger the sample the more accurate)
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6
Q

Describe how investigate the distribution of organisms using a quadrat

A
  • Mark out a ling in the area you want to study

- Collect data along all points of the line using quadrats placed next to each other

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7
Q

What do food chains show?

A

-What has been eaten by what in the food chain

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8
Q

What is a producer?

A

The first organism in the food chain who makes their own food using energy from the sun

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9
Q

What are consumers?

A 
Organisms that eat other organisms
1 - primary
2 - secondary
3 - tertiary
Each stage is called a trophic level
The arrow always points to what is eating it
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10
Q

Pyramids of numbers

A
  • Each bar represents the number of organisms at that stage in the food chain
  • Does not have to be a pyramid shape
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11
Q

Pyramids of biomass

A
  • Each bar represents the mass of living material at that stage of the food chain (how much they weigh if all put together)
  • Almost always a pyramid shape
  • e.g. one fox weighs more than 100 flees
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12
Q

Pyramids of energy transfers

A
  • Show the amount of energy transferred at each trophic level
  • Always the right shape
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13
Q

How is energy transferred?

A

Along a food chain
- Energy from the sun is the source of energy for nearly all life on Earth
-

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14
Q

How is energy transferred?

A

Along a food chain

  • Energy from the sun is the source of energy for nearly all life on Earth
  • Plants get energy from the sun from photosynthesis
  • If a rabbit eats the plant not all of the energy will be transferred as it will be lost as heat
  • The amount of original energy from the sun is transferred less and less as you travel up the trophic levels
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15
Q

What do food webs show?

A

How food chains are linked

The arrows point to the what eats the organism

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16
Q

Describe the water cycle

A
  • Heat from the sun makes water evaporate from the land and sea turning it into water vapour (also evaporates from plants through transpiration)
  • Warm water vapour is carried upwards and as it rises it cools and condenses to form clouds
  • Water falls from the clouds as precipitation and is returned to the land and sea
  • It is an endless cycle
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17
Q

Describe the carbon cycle

A
  • The whole cycle is powered by photosynthesis
  • Green pants use the carbon from CO2 to make carbohydrates, fats and proteins
  • Eating passes the carbon compounds in the plant along to animals in a food chain or web
  • Both plant and animal respiration releases CO2 back into the environment
  • Dead plants and animals decompose
18
Q

Describe the carbon cycle

A
  • The whole cycle is powered by photosynthesis
  • Green pants use the carbon from CO2 to make carbohydrates, fats and proteins
  • Eating passes the carbon compounds in the plant along to animals in a food chain or web
  • Both plant and animal respiration releases CO2 back into the environment
  • Dead plants and animals are decomposed by bacteria and fungi which releases CO2 back into the environment by respiration
  • Some useful plant and animal products (e.g. wood and fossil fuels) are burned (combustion) which releases CO2 back into the environment
  • There is a fixed amount of carbon in the world meaning it is all recycled
19
Q

How much nitrogen is in the atmosphere?

A

78% nitrogen gas which is very unreactive so cannot be used directly by plants and animals

20
Q

Why is nitrogen needed?

A

For making proteins for growth

21
Q

How to plants get nitrogen?

A

From the soil

22
Q

What is nitrogen fixation?

A

Nitrogen fixation is the process of turning N2 from the air into nitrogen compounds in the soil which plants can use

23
Q

Describe the process of nitrogen fixation

A

Lightning - the energy from the lightning bolt makes nitrogen react with oxygen in the air to give nitrates
Nitrogen-fixing bacteria - in roots (nodules )and soil

24
Q

What bacteria is involved in nitrogen fixation?

A

Decomposers - break down proteins (in dead animals and plants) and urea (in animal waste) and turn them into ammonia
Nitrifying bacteria - turn ammonia in decaying matter into nitrates
Nitrogen-fixing bacteria - turn atmospheric N2 into nitrogen compounds that plants can use
Denitrifying bacteria - turn nitrates back into N2 gas. This is not beneficial to living organisms

25
Q

How is carbon monoxide poisonous?

A
  • When fossil fuels are burnt without enough air supply they produce carbon monoxide gas
  • If CO combines with red blood cells it prevents them from carrying oxygen
  • CO is mostly released in car emissions
  • Most modern cars have a catalytic converter that turn CO into CO2 which is less dangerous
26
Q

How is acid rain produced?

A
  • By sulphur dioxide
  • Burning fossil fuels released CO2 and SO2
  • Sulfur dioxide
27
Q

How is acid rain produced?

A
  • By sulphur dioxide
  • Burning fossil fuels released CO2 and SO2
  • Sulphur dioxide comes from sulphur impurities in the fossil fuels
  • When this gas mixes with rain clouds it forms dilute sulphuric acid
  • This falls as acid rain
  • Internal combustion engines in cars and power stations are the main causes of acid rain
28
Q

How does acid rain kill fish and trees?

A
  • Acid rain causes a lake to become more acidic which kills sensitive organisms and destroys ecosystems
  • Acid rain can kill trains as it damages leaves and releases toxic substances from the soil making it hard for the trees to take up nutrients
29
Q

What are greenhouse gases?

A

Gases that trap in heat energy from the sun and increase the overall temperature of Earth
These gases include water vapour, carbon dioxide and methane

30
Q

What are greenhouse gases?

A

Gases that trap in heat energy from the sun and increase the overall temperature of Earth
These gases include water vapour, carbon dioxide and methane

31
Q

What is adding to the greenhouse effect?

A
  • Carbon dioxide
  • Methane
  • Nitrous oxide
  • CFCs
32
Q

How does carbon dioxide add to the greenhouse effect?

A
  • Humans release CO2 in the atmosphere in car exhausts, industrial processes and burning fossil fuels
  • Cutting down forests increases the amount of CO2 as there are less trees using it in photosynthesis
33
Q

How does methane add to the greenhouse effect?

A
  • Methane gas is produced naturally from rotting plants in marshland
  • Manmade sources of methane include rice growing and cattle rearing
34
Q

How does nitrous oxide add to the greenhouse effect?

A
  • Nitrous oxide is released naturally by bacteria in soils and the ocean
  • A lot more is released from soils after fertiliser is used
  • Also released from vehicle engines and industry
35
Q

How do CFCs add to the greenhouse effect?

A
  • Manmade chemicals that were once used in aerosol sprays and fridges
  • Not produced as much anymore as they damage the ozone layer
  • Leaks from old fridges release CFCs
36
Q

How do CFCs add to the greenhouse effect?

A
  • Manmade chemicals that were once used in aerosol sprays and fridges
  • Not produced as much anymore as they damage the ozone layer
  • Leaks from old fridges release CFCs
37
Q

Describe eutrophication

A
  • Fertilisers enter the water after raining, adding extra nutrients (e.g. nitrates and phosphates)
  • The extra nutrients cause algae to grow fast and block out light
  • Plants can’t photosynthesise due to lack of light and start to die
  • With more food available microorganisms that feed on dead plants increase in number and deplete (use up) all the oxygen in the water
  • Organisms (e.g. fish) die
38
Q

How can eutrophication be caused?

A
  • Using too much fertiliser that enters lakes through rain
  • Pollution by sewage as it contains lots of phosphates from detergents (e.g. washing powder) and also contains nitrates from urine and faeces
39
Q

How does deforestation affect leaching?

A
  • Trees take up nutrients from the soil before they can be washed away
  • No trees mean nutrients get washed away and not replaced leaving infertile soil
40
Q

How does deforestation affect soil erosion?

A
  • Tree roots hold soil together

- When trees are removed soil can be washed away by the rain leaving infertile ground

41
Q

How does deforestation affect the water cycle?

A
  • Trees stop rainwater reaching rivers too quickly
  • When they’re cut down rainwater can run straight into rivers which leads to flooding
  • Transpiration from trees releases some of the rainwater back into the atmosphere
  • When they’re cut down the overall climate can become drier
42
Q

How does deforestation affect the levels of oxygen and carbon dioxide?

A
  • Forests take up CO2 by photosynthesis and release it slowly when they decompose
  • When trees are cut down and burnt the stored carbon is released
  • Fewer trees means less photosynthesis which releases less oxygen and causes levels to drop

Biology (9 decks)

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