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GCSE- Biology > Topic 9- Ecosystems > Flashcards

Topic 9- Ecosystems Flashcards

1
Q

What is an organism?

A

-A singular
-living thing

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2
Q

What is a population?

A

-The number of the
-same species
-in an area

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3
Q

What is a community?

A

-Different populations living
-in an area

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4
Q

What is an ecosystem?

A
  • Abiotic and biotic factors
  • interacting
  • together in an area
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5
Q

Biotic vs Abiotic

A

-Biotic is living
-Abiotic is not living e.g rocks/ light

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6
Q

What is the importance of interdependence?

A
  • If one population increase/ decrease too heavily it can impact other species
  • grass -> Rabbit -> Fox ->
    • With less foxes, rabbits increase
    • Grass decreases and rabbits die
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7
Q

Parisitism?

A
  • An organism lives on or inside another
  • The parasite benefits and the host is harmed
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8
Q

Mutualism?

A
  • 2 species live together
  • Both benefit
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9
Q

Parasite example?

A

Tape worm
- Hooks attach to small intestine
- Large SA to absorb nutrients
- Release eggs in feaces

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10
Q

Mutualism example?

A

Bees and flowers
-Bees receive nectar
-Pollen is spread for reproduction

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11
Q

Core Practical: Investigate the relationship between organisms
and their environment using field-work techniques, including
quadrats and belt transects

A

-Place quadrate at the same intervals
- Count number of species in the quadrate
- Use the light meter to find the light intensity
- Also test for other abiotic factors e.g pH or temperature

-Belt transects, form a graph/ coordinates
- Roll a dice to find random coordinates
- Record light + number of species

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12
Q

How to estimate number of species in a total area using data from quadrats and belt transects?

A

Avg number of species x total area

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13
Q

How does the energy transferred up the food chain change?

A
  • Only 10% of energy is passed when consumed
  • Rest of energy is lost to surroundings e.g heat/ KE/ faeces
  • Or used to grow, reproduce
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14
Q

What is the food chain system broken down?

A

Primary producer ->
Primary consumer ->
secondary consumer ->
tertiary consumer ->
quaternary consumer ->
(Decomposers eat everything)

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15
Q

What does the arrow in the food chain follow?

A

Movement of energy

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16
Q

What is biomass in reference to the food chain?

A

Mass of all species on a specific trophic level

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17
Q

Why are there normal only 4-5 trophic levels?

A

There isn’t enough biomass/ energy (biomass is converted into energy) for more trophic levels

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18
Q

How do the trophic levels increase?

A

-Tropic level 1 is the primary producer
- Tropic level 2 is the primary consumer
-3 is the secondary consumer

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19
Q

Dangers of fish farming? X6

A

EUTROPHICATION- Fish excretion (faeces and gills) contains ammonia -> Toxic
- Densely populated, easy spread of disease and parasites
- Escaped fish can compete with native species for resources
- Escaped fish can spread disease and parasites.
- Consumers could eat antibiotics (in fish) and get immunity
- Carnivores fish (salmon) need to eat lots of fish (damage population)

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20
Q

Why is introduction of non-indigenous species dangerous?

A
  • Compete for resources (food, shelter)
  • Can bring disease
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21
Q

How did the grey squirrel hurt the red squirrel population?

A

-Grey squirrels are more aggressive
- Grey squirrels are larger
- Grey squirrels have a more versatile diet
- Left red squirrels stress, unable to reproduce
- Grey squirrels have 2-7 litter vs Red 3-4 litter
- Grey squirrels carry disease ( squirrel box)

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22
Q

What is eutrophication?

A
  • Nutrients in water causes microorganisms/ algae to grow,
  • Deplete oxygen and sunlight levels
  • causes plants and animals to die
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23
Q

How is eutrophication caused by humans?

A
  • Sewage (ammonia/ nitrogen)
  • Fertilisers (nitrogen)
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24
Q

Why is it beneficial to maintain biodivesity?

A
  • Maintains balance food chain
  • Mangroves protect coastlines
  • Vegetation prevents floods/landfalls
  • Herbal/ wild medicine (sloths fungus cures cancer)
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25
What is food security?
The amount of food needed to support an area
26
How is food security affected?
- Rise in population, more to feed - Pathogens and pests attack crops - Farming animals means less vegetable consumption - Climate change causing extreme weather - Increased cost of farming
27
What is the carbon cycle breakdown?
- Carbon in atmosphere - Plants and algae absorb carbon for photosynthesis (made into protein, fats and carbohydrates) - Animals eat plants with carbon in/ aerobic respire -> Carbon back to atmosphere - Decomposers respire (eat carbon filled animals and plants)
28
What happens to carbon if there is a lack of oxygen in the soil?
- Decomposing microorganisms can't function effectively - Carbon turns into fossil fuels
29
How do decomposers benefit the soil?
Release mineral ions to the soil
30
What is the natural water cycle?
- Ocean evaporates - Form clouds - Precipitation (potable water) - Consumption (Plants, animals) - Streams ( Through-flow) back to ocean
31
What is desalination?
- Evaporating sea water and collecting the condensed fresh water.
32
What are the negatives of desalination?
- Uses lots of energy - Lots of waste salt returned to ocean - Only richer countries can produce
33
What are the positives of desalination?
- 97% of water is saline, less water insecurity - Poor countries can purchase water
34
What is reverse osmosis?
- Use energy to push salt water at high pressure through a - Polymer membrane - With small holes extract the clean water
35
What are the negatives of reverse osmosis?
- High waste salt quantity back in sea - Membranes easily clogged
36
What are the positives of reverse osmosis?
- 97% of water is saline, less water insecurity - Uses less energy than desalination
37
What is the nitrogen cycle breakdown?
- Nitrogen too unreactive in atmosphere - Lightning/ nitrogen-fixing bacteria convert nitrogen into nitrates - Nitrates absorbed by plants for growth (proteins/ amino acids) - Plants eaten by animals ( proteins/ amino acids) --------- Decomposing bacteria convert nitrates from dead plants and animals into ammonia - Nitrifying bacteria converts ammonia into nitrates - Denitrifying bacteria converts nitrates back into nitrogen
38
What does denitrifying bacteria do?
- Converts nitrates into nitrogen - Returns nitrogen back into atmosphere - Remove nitrogen from the cycle
39
What does nitrogen fixing bacteria do?
-Turns unreactive nitrogen into nitrates
40
What does nitrifying bacteria do?
-Converts ammonia back into nitrates
41
What does decomposing bacteria do?
- Converts nitrogen from dead organisms into ammonia
42
Where is nitrogen-fixing bacteria found?
- Root nodules Legumes: - Onions - Clover - Beans
43
Why do farmers plant legumes in between crop cycles?
- Legumes have root nodules - Nitrogen-fixing bacteria replenish nitrates in soil
44
Why do farmers want high nitrate levels in the soil?
- Crops grow faster
45
How can farmers make soil more nitrate rich?
- Chemical fertilisers (ammonium nitrate) - Animal manure
46
Why is little oxygen in soil bad for farmers?
- As denitrifying bacteria is anaerobic, nitrates in the soil will be converted back into nitrogen - Nitrogen-fixing bacteria is aerobic, nitrogen won't be converted into nitrates
47
What animals show that water is highly polluted?
- Sludge worms - Rat-tailed maggot - Blood worm - Adapted aspects to survive on low oxygen e.g through skin, tail extends to air.
48
What animals show water is fresh?
- Freshwater shrimp - Stonefly - Need oxygen rich/clean water
49
What are the positives of using indicator species for monitoring pollution?
- Gives a general idea of polluted vs cleaner areas - Natural monitor, cheap
50
What lichen can survive in polluted air?
- Crusty lichen
51
What lichen can survive in slightly polluted air?
- Leafy lichen
52
What lichen can only survive in clean air?
- Bushy lichen
53
What are these lichens sensitive about in the air?
Sulphur dioxide and other pollutants
54
What are the negatives of using indicator species for monitoring pollution?
- Can't determine the actual chemical levels of pollution
55
How does temperature affect the rate of decomposition?
- Warmer, more enzyme activity - Too hot, denature enzymes - Too cold, microorganism do not reproduce
56
How can we test how temperature affects decomposition and what are the problems?
- Wait for milk to curdle in two temperatures (outside the fridge) -------> Not a distinct temperature, as room temp changes --------> Takes ages - Place lipase in milk to break down the lipids into fatty acids (IN A WATER BATH) - fatty acids make it acidic - - Use cresol red (indicator) purple in alkali, yellow in acid - Add alkali (sodium carbonate) to milk to begin it off as alkaline.
57
How can we improve the second/ lab method of testing temperature on the rate of decomposition?
- Use an electric water bath
58
What and why does lack of oxygen do to the rate of decomposition?
- Slows decomposition - Microorganisms need oxygen to respire aerobically.
59
What and why does lack of water do to the rate of decomposition?
- Lowers decomposition - Needed for transport - Needed for microorganisms to digest
60
How to calculate rate changes in the decay of biological material?
- Change in pH/ Time (hours)

GCSE- Biology (9 decks)

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