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Edexcel Biology B A-level > Ecosystems 10 > Flashcards

Ecosystems 10 Flashcards

1
Q

What is an ecosystem?

A

An environment that includes all of the organisms living in a particular area

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2
Q

What is a community?

A

All the populations of all the different species of organisms living in a habitat at any one time

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3
Q

What are the four sizes of ecosystems?

A

-Biosphere
-Biome
-Habitat
-Microhabitat

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4
Q

What is meant by an animals trophic level?

A

An animals feeding relationship with other organisms or its position in a food chain

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5
Q

What are the five trophic levels?

A

-Producers
-Primary consumers
-Secondary consumers
-Teritary consumers
-Decomposers

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6
Q

What is a pyramid of numbers?

A

Shows the number of organisms at each trophic level

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7
Q

What is one advantage of using pyramid of numbers?

A

Easiest to measure

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8
Q

What is one disadvantage of using pyramids of numbers?

A

Can be distorted by large organisms

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9
Q

What does a pyramid of biomass show?

A

The combined mass of all the organisms in a particular habitat

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10
Q

What is an advantage of using a pyramid of biomass?

A

More accurate and realistic model of trophic levels

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11
Q

What is a disadvantage of using pyramid of biomass?

A

Dry mass has to be used and this involves destroying the material

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12
Q

Why can’t we use wet mass to measure biomass?

A

Wet mass is inaccurate as it is affected by water uptake, drinking and defaecating

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13
Q

What does a pyramid of energy show?

A

Represents the total energy store of the organisms at each level

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14
Q

What is an advantage of using pyramids of energy?

A

It is the most accurate way to represent a food chain

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15
Q

What is a disadvantage of using pyramids of energy?

A

It is extremely difficult to measure and uses an outdated model of energy

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16
Q

How can we quantify how productive an ecosystem is?

A

By using Net primary productivity and Gross primary productivity

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17
Q

What does productivity of an ecosystem depend on?

A

How favourable abiotic and biotic factors are

18
Q

What is Gross primary productivity (GPP)?

A

Total energy resulting from photosynthesis or rate at which light from the sun catalyses production of new plant material

19
Q

What is the formula for Net primary productivity (NPP)?

A

GPP - R (respiration)

20
Q

What does NPP take into account?

A

The energy lost during respiration

21
Q

What is one limitation of efficiency calculations?

A

You have to measure: number of abundant species, amount of organisms and body mass
Making it difficult to measure

22
Q

What is the definition of succession?

A

The change in an ecological community over time

23
Q

What is a plagioclimax community?

A

A final community due to human intervention

24
Q

What is a climatic climax community?

A

The only climax community possible in a given climax

25
Q

When does secondary succession occur?

A

After succession has been disrupted eg, a fire or flood

26
Q

What does succession result in?

A

-Increased species richness
-Increased biodiversity
-Food webs becoming more complex

27
Q

What is a climax community?

A

The most productive, stable community of organisms the environment can support

28
Q

What is the first species in primary succession?

A

Pioneer species

29
Q

How is soil formed in primary succession?

A

-Pioneer species penetrates bare rock
-Humus is created
-Leading to the formation of soil

30
Q

When is a quadrat used?

A

When measuring abundance of non-motile organisms

31
Q

What are individual counts?

A

Measure of the number of organisms in the area being sampled

32
Q

What is one limitation of using quadrants?

A

Limitations to how much area you can sample

33
Q

What is the ACFOR scale used for?

A

To measure abundance by describing abundance by 5 key terms

34
Q

What is one limitation of the ACFOR scale?

A

It is subjective and everyones definitions of the terms may be different

35
Q

What is a permanent quadrat?

A

A quadrat left there all the time to collect data over a long time

36
Q

What is a point quadrat?

A

Species that touch a pin put into the group are recorded to record percentage cover

37
Q

How are transects better than quadrats?

A

They are not random so data is systematic

38
Q

What is a line transect?

A

A tape is placed on the group and every organism that touches the line is recorded to measure abundance

39
Q

What is a belt transect?

A

Two tapes are lined opposite and the organisms on the ground between the lines are recorded

40
Q

When are transects used?

A

-Investigate link between distribution and abiotic factors
-Find correlations between abundance and abiotic factors

Edexcel Biology B A-level (13 decks)

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