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GCSE Biology > Ecosystems > Flashcards

Ecosystems Flashcards

1
Q

What is an ecosystem?

A

A distinct, self-supporting system of organisms which interact with each other and with the physical environment. They can be small or large.

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2
Q

What is the definition of an abiotic factor?

A

A non-biological/ non-living part of an ecosystem.

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3
Q

What is the definition of a biotic factor?

A

A living part of an ecosystem.

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4
Q

What is an example of an abiotic factor?

A

Soil
Water
Air

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5
Q

What is an example of a biotic factor?

A

Plants
Animals

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6
Q

What is the definition of a habitat?

A

Where specific organisms live.

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7
Q

What is the definition of the population in an ecosystem?

A

The number of a particular species in an ecosystem at a given time.

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8
Q

What is the definition of the community in an ecosystem?

A

Populations of different species added together.

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9
Q

What biotic factors may affect an ecosystem?

A
  • Plant material as food
  • Number of potential predators and prey
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10
Q

What abiotic factors may affect an ecosystem?

A
  • Purity of water/soil
  • Weather/light intensity
  • Amount of water - deep/shallow
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11
Q

Why would it be impractical to count every organism in an ecosystem?

A
  • There are too many
  • Some may be re-counted or not counted at all
  • May be difficult to tell apart different individuals.
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12
Q

What are quadrats?

A

Metal frames placed on the ground, so organisms within can be counted.

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13
Q

Why must sampling be random?

A

To avoid bias.

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14
Q

How can sampling be random?

A

Using dice to determine the X, Y coordinates where you place your quadrat.

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15
Q

How do you sample an area?

A

Using quadrats and percentage cover.

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16
Q

How do you determine the total population of a particular species in an area?

A

You sample, and then add up your sampling area to calculate the total.

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17
Q

What is biodiversity?

A

The variety of life on earth and the essential interdependence of all things.

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18
Q

What is a main feature of a highly biodiverse ecosystem, and what is an example of one?

A

A large variety of different species, a coral reef.

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19
Q

What do arrows in food chains show?

A

The flow of energy.

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20
Q

Where does energy in a food chain come from?

A

The producer creates its own food, using energy it gained from the sun.

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21
Q

How does a producer make its own energy?

A

Photosynthesis.

22
Q

What is a trophic level?

A

A level of feeding (trophic means feeding)

23
Q

What is a predator?

A

An animal which eats other animals.

24
Q

What is prey?

A

An animal which gets eaten by other animals.

25
Q

What does a decomposer do, and what is an example of one?

A

Consumes/ breaks down all organisms.
Fungi or bacteria

26
Q

What are the different types of consumers?

A
  • Primary Consumer
  • Secondary Consumer
  • Tertiary Consumer
  • Quaternary Consumer (Apex Predator)
27
Q

What does apex predator mean?

A

An animal that is a predator, but does not have any predators itself. (Top of the food chain)

28
Q

Why are food webs better than food chains? (On paper)

A

Food chains are oversimplified. Food webs show a collection of them, and show more interactions between organisms.

29
Q

Why are feeding relationship diagrams usually pyramid- shaped?

A

Energy is lost at each trophic level.

30
Q

How much energy is lost at each trophic level?

A

Approximately 90%

31
Q

Why do most food chains not have more than 5 trophic levels?

A

Too much energy is lost at each trophic level.

32
Q

Why is there a loss of energy at each trophic level (in animals)?

A
  • Egestion (feces)
  • Excretion (carbon dioxide, sweat, urine)
  • Temperature (respiration)
  • Movement
  • Not all of the organism is eaten ( tail, bones, organs, roots (plants) )
33
Q

What two types of pyramids are there when depicting food chains?

A
  • Pyramids of numbers
  • Pyramids of biomass
34
Q

What is biomass?

A

The dry mass (no water)

35
Q

How can you calculate an organism’s dry mass?

A

Put it in the oven at 101 degrees celcuis, then keep weighing and re-weighing until it no longer loses any mass.

36
Q

How can you calculate a species’ biomass?

A

Mass of living material x number of organisms.

37
Q

What are carbon atoms needed for in living organisms?

A

Making carbohydrates, proteins, lipids and DNA.

38
Q

How do plants and animals obtain their carbon?

A

Plants from carbon dioxide by photosynthesis, animals from plants by feeding.

39
Q

Which processes put carbon dioxide into the atmosphere?

A

Combustion
Respiration

40
Q

Which processes take carbon dioxide from the atmosphere?

A

Photosynthesis
Fossilisation

41
Q

What do nitrifying bacteria do?

A

Change ammonium into nitrites and then into nitrates.

42
Q

What do nitrogen fixing bacteria do in the root nodules?

A

Turn nitrogen gas into ammonium and then plant protein.

43
Q

What do denitrifying bacteria do?

A

Turn nitrates into nitrogen gas.

44
Q

What are nitrogen atoms needed for in living organisms?

A

Making DNA and proteins.

45
Q

How do plants and animals obtain their nitrogen?

A

Plants get it from nitrates in the soil by nitrification (and assimilation) and animals get it from plants by feeding.

46
Q

Which processes put nitrogen into the soil?

A

Lightning on nitrogen gas, nitrification, and nitrogen fixation.

47
Q

Which process takes nitrogen from the soil?

A

Denitrification

48
Q

What types of plants contain nitrogen-fixing bacteria in their root nodules?

A

Legumes

49
Q

How do the bacteria in the root nodules of legumes benefit?

A

They get glucose.

50
Q

How do the legumes with bacteria in their root nodules benefit?

A

They get ammonia, which can be converted into amino acids. (nitrification can occur)

GCSE Biology (14 decks)

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