B4 Flashcards

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1
Q

What is an ecosystem?

A

All the living organisms and physical conditions in an area

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2
Q

What is a community?

A

The organisms within the ecosystem

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3
Q

What is a habitat?

A

Where the community of an ecosystem live

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4
Q

What is the population?

A

The total number of organisms of each species

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5
Q

What are the 3 groups of organisms in a community?

A

Producers
Consumers
Decomposers

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6
Q

What are producers?

A

Organisms that make their own food by photosynthesis- all plants and algae

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7
Q

What are consumers?

A

Organisms that cannot make their own food - they have to eat other organisms for energy - all animals

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8
Q

What are decomposers?

A

A speak o group of consumers that get energy by feeding on dead or decaying material

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9
Q

What is the biomass?

A

The mass of living material present

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10
Q

What is a trophic level?

A

Each step in the food chain

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11
Q

What is a food web?

A

Multiple food chains linked together

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12
Q

What 2 factors affect an ecosystem?

A

Biotic factors
Abiotic factors

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13
Q

What is a biotic factor?

A

Living factors such as trees, squirrel and hedgehogs - the number of these organisms also counts

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14
Q

What is an abiotic factor?

A

Non-living factors such as rainfall and temperature and oxygen availability

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15
Q

In terms of factors, what is competition?

A

The most common biotic factor

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16
Q

How does light intensity affect communities?

A

Light needed for photosynthesis so lower light intensity causes leaves to be larger

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17
Q

How does temperature affect communities?

A

It affect the enzymes that control metabolic reactions - plants and cold-blooded animals develop more rapidly in warmer temperatures as their metabolism will be better (warm blooded animals are not affected as much)

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18
Q

How does moisture level affect communities?

A

Lack of water usually means death for most organisms as water is a main component of blood plasma - lack of water causes plants to wilt.

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19
Q

How does lack of water affect plants?

A

They wilt because water is needed for to keep their cells turgid, which keeps plants upright - also needed for photosynthesis

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20
Q

How does soil pH affect communities?

A

Some plants grow better in acidic soil (ferns and rhododendrons)
Some plants grow better in alkaline soil (cucumbers and cauliflower)

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21
Q

What is competition?

A

Plants and animals need a number of different materials from their surroundings - they have to compete for these resources

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22
Q

What do plants need to survive?

A

Light
Water
Breeding partners
Space (territory)
Shelter

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23
Q

What do animals need to survive?

A

Food
Water
Breeding partners
Space (territory)
Shelter

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24
Q

What is interdependence?

A

How different organisms depend on each other within a community

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25
Q

What are ecological relationships?

A

The interactions between organisms

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26
Q

What are the 3 types of ecological relationships?

A

Predation
Mutualism
Parasitism

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27
Q

What is predation?

A

The name of the relationship between predator and prey - the size of the both populations directly affect each other

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28
Q

What is mutualism?

A

A mutualistic relationship between two organisms when both of the get benefits from the relationship

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29
Q

What is an example mutualism?

A

Oxpeckers that live on buffaloes - eat ticks and fleas on the buffalo’s skin - they get food while the buffalo gets free of irritation and potential disease

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30
Q

What is parasitism?

A

When only one organism in the relationship gains but the host suffers.

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31
Q

What is a parasite?

A

The organisms that get the benefits of a parasitic relationship

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32
Q

What is the host?

A

The organism that suffers in a parasitic relationship

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33
Q

What are examples of parasitism?

A

Mosquitoes and humans
Tapeworms in an animal’s digestive system

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34
Q

What is a pyramid of biomass?

A

The flow of biomass in a community

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35
Q

What are the disadvantages of the pyramid of numbers ?

A

They don’t show the number of organisms involved or the size of the biomass transferred

36
Q

How are pyramids of biomass organised?

A

The produce of the food chain at the bottom with the next trophic levels placed above

37
Q

What are the usual trends (not all) in pyramids of numbers ?

A

Number of organisms decrease as you up the trophic levels
Size of organisms increases as you go up the trophic levels

38
Q

What is good about pyramids of biomass?

A

They plot the amount of biomass at each level - takes into account the number of organisms and the size of the organisms

39
Q

How do scientists plot pyramids of biomass?

A

Measure the average mass of the organisms and multiply it by the number of organisms

40
Q

What is special about pyramids of biomass?

A

They are scale diagrams so the width of the bar represent the biomass of organisms at each trophic level

41
Q

Why isn’t all the energy form the sun transferred to chemical energy in the plant?

A

Most of the light is reflected from the leaf
Remaining energy that is transferred is limited by factors such as temperature or water availability

42
Q

What are ways in which biomass can be lost between trophic levels?

A

Not all of an organism is eaten/consumed
Some of the biomass is used for respiration - produces ATP which can be used for movement, respirations causes thermal energy to be transferred to the environment
Some parts of an organism cannot be digested and are removed in faesces
Waste products are lost such as urine and faeces

43
Q

What is egestion?

A

When parts of an organism cannot be digested and are so removed via the faeces (hair and teeth)

44
Q

What is excretion?

A

Waste products produced by the body are lost through excretion (urea lost in urine)

45
Q

How do calculate the efficiency of biomass transfer?

A

Biomass after transfer (weight gain) - g or Kg
—————————————————————— x 100
Biomass before transfer (amount consumed) - g or Kg

46
Q

What is nutrient cycling?

A

Plants obtain nutrients needed from soil
Passed onto animals when plant is eaten
When plants lose leaves and organisms die, decomposers release the trapped nutrients
Many nutrients released back into soil or atmosphere
Repeat

47
Q

What materials are cycled?

A

Carbon
Water
Nitrogen

48
Q

Where can carbon be trapped sometimes?

A

In the oceans and rocks

49
Q

What are the attributes of nitrogen?

A

Makes up nearly 80% of the atmosphere
Organisms use it to make DNA and proteins
Most organisms only use nitrogen when it is part of a compound - such as nitrate

50
Q

What is nitrifying bacteria?

A

Bacteria that convert ammonia into nitrates in the soil to be absorbed by plants

51
Q

What is denitrifying bacteria?

A

Bacteria that remove nitrogen from the cycle by breaking down nitrates in the soil back to nitrogen gas which gets released back into the atmosphere

52
Q

What do decomposing bacteria do?

A

Convert dead matter into ammonia - break down organic matter containing nitrogen into nitrogen accessible in soil

53
Q

What do nitrogen-fixing bacteria do?

A

Converts atmospheric nitrogen into nitrates by nitrogen fixation

54
Q

What is nitrogen fixation?

A

Chemical process in which atmospheric nitrogen is converted into nitrates in the soil

55
Q

What is a more uncommon way of nitrogen fixation?

A

When lightning strikes the ground, it converts nitrogen gas into nitrates

56
Q

How do animals faeces relate to the nitrogen cycle?

A

It contains ammonia which can be converted back into nitrates

57
Q

What type of plants contain nitrogen-fixing bacteria?

A

Peas, beans clover (legumes)

58
Q

How does carbon cycle across the environment?

A

It cycles between the atmosphere, living organisms and fossil fuels

59
Q

Why is water important?

A

It is an essential component of any ecosystem because all living organisms need to drink or absorb water to suevive

60
Q

What is the main way in which carbon is removed from the atmosphere?

A

Plants, algae and phytoplankton convert carbon into the simple form of glucose

61
Q

How does carbon get transferred from plants?

A

When plants get eaten, they transfer their carbon in the form of glucose

62
Q

What are ways in which carbon in the atmosphere increases?

A

Plant respiration
Animal respiration
Fossil fuel combustion
Decomposition of animals + waste products
(Look up carbon cycle picture if confused)

63
Q

Why is the water cycle important?

A

When water moves, it a,so transports nutrients - helps replenish the nutrients that have already been used in an environment

64
Q

What two things cause water vapour in the atmosphere?

A

Transpiration
Evaporation

65
Q

What is transpiration?

A

Loss of water vapour from plants directly to the atmosphere

66
Q

What is percolation?

A

Water trickles though gaps in soils and rocks

67
Q

What is evaporation?

A

The sun beats the earth’s surface (ocean) and water is turned from a liquid into water vapour - moist air

68
Q

What is condensation?

A

As moist air rises, it cools - water vapour condenses back into liquid water droplets forming clouds

69
Q

What is precipitation?

A

As water droplets get heavier, they fall as rain, snow or hail

70
Q

What is the water cycle?

A

Any order…
Precipitation
Percolation goes to plants and ocean
Transpiration and evaporation causes water vapour
Condensation of water vapour
Those clouds cool into rain clouds
Precipitation

71
Q

Why does the level of atmospheric carbon dioxide vary?

A

Photosynthesis only occurs in the light
Respiration is carried out throughout the day and night - releasing CO2 at a (somewhat) consistent rate.

72
Q

Why has the average atmospheric carbon dioxide levels increased over the past 200 years?

A

Human activities - combustion of fossil fuels and deforestation

73
Q

What are decomposers?

A

Microorganisms that break down or decay organic material at an organic level

74
Q

What are saprophytes?

A

Organisms that feed on dead material

75
Q

What are detritivores?

A

Small animals that speed up decomposition by shredding organic material into small pieces - creates a larger surface area for decomposers to work on

76
Q

What happens while decomposers are breaking down dead organic material?

A

Through decomposition, nutrients are released which can be recycled

77
Q

How do decomposers break down organic matter?

A

The bacteria and fungi release bacteria which break down sugarcanes in the organic matter

78
Q

How do decomposers release nutrients?

A

They absorb the soluble nutrients into their bodies when breaking down organic matter

79
Q

How do decomposers use the nutrients that they absorb?

A

Growth and repair

80
Q

How do decomposers pass on nutrients?

A

They will be eaten, resulting in nutrients being passed on - some nutrients are released directly into the soil/environment

81
Q

What factors affect the rate of decomposition?

A

Warm temperatures
Moist environments
Aerobic conditions

82
Q

How does a high temperature affect the rate of decomposition?

A

Enzymes used by the microorganisms denature and prevents decomposition (often kills the microorganism)

83
Q

How do low temperatures affect the rate of decomposition?

A

Slows it down as the rates of enzyme-controlled reactions are reduced - rate of microorganism replication is also slow

84
Q

How do moist environments affect the rate of decomposition?

A

If not enough water is available - reaction within the microorganism stop or slow down - reduces or stops the process of decomposition

85
Q

How do aerobic conditions affect the rate of decomposition?

A

Oxygen is needed for microorganisms to respire - anaerobic conditions stop most forms of decomposition as the microorganisms will die

86
Q

What is the formula for rate of decay?

A

Change in mass (g)
—————————
Time (day)

87
Q

What are the units for “rate of decay”?

A

Grams per day