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GCSE Biology > SB9 > Flashcards

SB9 Flashcards

Ecosystems and material cycles

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1
Q

Define ecosystem

A

The living + non-living parts of a specific area

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2
Q

Define habitat

A

The non-living part of an ecosystem

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3
Q

Define community

A

All population of all organisms in an ecosystem

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4
Q

Define population

A

all members of one species in an ecosystem

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5
Q

Define niche

A

The role of one species within an ecosystem

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6
Q

Define interdependent

A

Species that rely on others in a community for resources

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7
Q

Define biomass

A

The total tissue mass that makes up an organism

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8
Q

Define the purpose of a food web

A
  • Shows feeding relationships between organisms in a community
  • Used to predict what will happen if change occur
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9
Q

Define abiotic factors + give examples

A
  • Physical and chemical non-living factors that may have an effect on an ecosystem
  • Light, temp, space, soil pH, wind, oxygen/carbon dioxide concentration
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10
Q

Define biotic factors + give examples

A
  • Living components in an ecosystem that affect other living organisms
  • Predators, Competition
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11
Q

Define indicator species

A

Organisms whose presence signifies the presence/absence of pollution

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12
Q

Define eutrophication

A

When a water body becomes overly enriched with nutrients, leading to the plentiful growth of simple plant life

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13
Q

Define parasitism

A

Relationship where one organism benefits by feeding off of a host - causes harm to the host

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14
Q

Define mutualism

A

Relationship where organisms live together and mutually benefit from it

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15
Q

Define biodiversity

A

Variety of plant and animal life in a habitat

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16
Q

Define reforestation

A

Planting a new forest where an old one has been cut down

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17
Q

Define the purpose of conservation programs

A

Made to protect rare/endangered species

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18
Q

Define captivity

A

Where endangered animals are bred in protected environments to increase their numbers

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19
Q

Define food security

A

Having sufficient access to safe and healthy food at all time

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20
Q

Define potable

A

Safe to drink

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21
Q

Define the role of nitrifying bacteria

A

Turns ammonia in decaying matter into nitrates and nitrites

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22
Q

Define the role of nitrogen-fixing bacteria

A

Turns nitrogen gas in the environment into ammonia in order to create ammonium ions

23
Q

Define the role of denitrifying bacteria

A

Turns nitrites and nitrates back into nitrogen gas

24
Q

Define the purpose food preservation + give examples

A
  • Slow down the rate of growth of decomposers to keep food fresher for longer
  • Adding salt/sugar, modified atmosphere packaging, canning, pickling, sealing, chilling, freezing
25
Q

Define compost

A

Waste garden material that is well decayed

26
Q

How do you measure population

A
  • Take samples using quadrats that are placed randomly (using an RNG) in an area split into squares
  • Number of individuals in each quadrat is counted
27
Q

What is the calculation for population size

A

number of organisms in all quadrats * (total area/ combined area of all quadrats)

28
Q

What are food chains also known as

A

Trophic levels

29
Q

Place these in order and describe their trophic level:
Carnivore
Autotroph
Herbivore

A

Autotroph - producer
Herbivore - primary consumer
Carnivore - secondary

30
Q

How to measure the effect of abiotic factors

A
  • Use a belt transect
  • Peg out a long tape measure (>20m) starting in an area with none - heavy shade
  • Make measurements at regular intervals
  • Place top left hand corner of quadrat at measurement point and measure + record the abiotic factors at that area
  • Record abundance of selected plant
  • Repeat at each measurement point
31
Q

Why do we not randomly place quadrats when measuring the effect of abiotic factors

A

So we can observe a gradual change in effect

32
Q

What is water pollution caused by

A

Poisonous substances released by factories e.g mercury, fertilisers, sewage

33
Q

Advantages of indicator species

A

+ Easy to locate in appropriate places
+ Don’t require a lot of equipment to collect them
+ Abundance gives idea of long-term health of area

34
Q

Disadvantages of indicator species

A
  • Doesn’t give accurate information about level of pollution
  • Doesn’t give idea of rapid changes in pollution levels
35
Q

How does malaria work

A
  • Mosquito sucks blood of previously infected person
  • Mosquito bites another person inputting protists into their bloodstream
  • Protists travel from blood - liver - liver cells
  • Protists multiply in the liver and eventually burst out and into blood cells
  • Protists multiply in blood and burst in a cycle
  • Destruction of red blood cells = fatigue, fever, anamemia
36
Q

Advantages of fish farming

A

+ Better fed fish
+ Produces more fish

37
Q

Disadvantages of fish farming

A
  • Kept in small spaces
  • Parasites spread easier
38
Q

How does eutrophication work

A
  • Fertilisers are added to field, heavy rain washes fertilisers off
  • Nitrates and phosphates dissolve in soil water and those not taken up are washed into a stream
  • Increase nitrate and phosphate concentration in water leads to rapid surface algae growth
  • Blocks sunlight from passing and reaching underwater plants so they die and less oxygen is produced
  • Decompsers increase oxygen usage
  • Fish die due to lack of oxygen to respire
39
Q

What is food security reduced by

A
  • Increased population
  • Climate change
  • New pests and pathogens
  • Armed conflict
40
Q

Describe the water cycle

A
  • Evaporation = water in bodies of water turn to gas
  • Condensation = water vapour cools and turns in clouds
  • Transport = clouds pushed far away by strong winds
  • Precipitation = rain/snow/sleet falls from the sky
  • Surface runoff = excess water runs along the surface of wet ground
  • Infiltration = water that has fallen and is absorbed into the ground and stored by aquifiers
  • Transpiration = water is constantly pulled up to the leaves of plants and is once again evaporated
41
Q

How is water made potable

A
  • Filtration = remove debris
  • Chlorination = to kill any pathogens
42
Q

How is seawater made into freshwater

A
  • Desalination (boiling/reverse osmosis)
  • Distillation
43
Q

What is decay caused by

A

Decomposers (microorganisms)

44
Q

Why is nitrogen necessary

A

It is needed to create nitrogen containing compounds such as DNA and proteins

45
Q

How to increase nitrogen concentration

A
  • Artificial/natural fertilisers
  • Crop rotation
46
Q

Advantages and disadvantages of artificial fertilisers

A

+ Easy to use
+ No risk of pathogens
- Expensive
- Few types of nutrients

47
Q

Advantages and disadvantages of natural fertilisers

A

+ Cheaper
+ Allows animal waste to be removed
- Less concentrated nutrients as they have complex chains of nitrogen
- High risk of pathogens

48
Q

How does crop rotation help soil

A
  • Increase fertility by adding nitrates from crop containing nitrogen-fixing bacteria
49
Q

What types of crop contain nitrogen-fixing bacteria

A
  • Legumes
  • Fallow
  • Green manure
50
Q

Why is compost good for soil

A
  • ## Increases soil fertility by increasing the number of nutrients
51
Q

What is rate of decomposition affected by

A
  • Number of organisms
  • Oxygen level
  • Water
  • Soil pH
  • Temperature
52
Q

How do you calculate rate of decomposition

A

Mass lost/number of days

53
Q

Why is interdependence important

A

It allows organisms to depend on each other to prevent damages to the ecosystem

GCSE Biology (6 decks)

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