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Biology Year 2 > Chapter 13 - Energy And Ecosystems > Flashcards

Chapter 13 - Energy And Ecosystems Flashcards

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1
Q

What are ecosystems

A

The abundance and distribution of organisms which are controlled by biotic and abiotic factors
They are dynamic

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2
Q

What is meant by population

A

All of the organisms of a single species in a habitat

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3
Q

What is a community

A

All of the organisms of all species in a habitat

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4
Q

What is a habitat

A

The place where an organisms lives

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5
Q

What is a niche

A

The role of a species in an ecosystem

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6
Q

What is a trophic level

A

A stage of the food chain

Eg producer, primary consumer, secondary consumer

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7
Q

What is meant by biotic and abiotic factors

A

Living and non living

Eg competition and temperature

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8
Q

What is meant by gross primary production (GPP)

A

The total amount of energy made by producers, per unit area per unit time

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9
Q

What is meant by respiratory loss (R)

A

The energy used by organisms for respiration

Eg active transport, movement (muscle contraction), heat

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10
Q

What is meant by net primary productivity NPP

A

The amount of chemical energy a producer stores as energy per unit area per unit time
This is therefore the total amount of energy available to the next trophic level

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11
Q

What is the formula to work out net primary productivity

A

GPP - R

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12
Q

How do you calculate energy transfer efficiency

A

Net production/total energy ingested x 100

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13
Q

How do you work out net production

A

Total energy ingested - (respiratory loss + Excretion)

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14
Q

What percentage of energy is passed from sunlight to producer, producer to primary consumer and primary consumer to secondary consumer

A

Roughly 2%, 10%, 10-15%

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15
Q

Why is little energy passed from sunlight to producer

A
  • Light can be reflected off leaf
  • Can be reflected off a non-photosynthetic region eg bark
  • Lost as heat energy
  • Could be wrong wavelength
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16
Q

Why is little energy passed from producer to primary consumer

A
  • Respiratory loss as plant uses energy for metabolic processes eg active transport
  • Lost as heat energy
  • Not all of the plant is eaten
  • Some that is eaten is not digested
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17
Q

Why is little energy passed from primary consumer to secondary consumer

A
  • Respiratory loss as primary consumer uses energy for metabolism eg muscle contraction
  • Lost as heat
  • Not all of primary consumer is eaten
  • Not all of primary consumer eaten is digested
18
Q

How can energy transfer efficiency be increased in plants/crops

A
  • Use of fertilisers you prevent growth being limited by lack of nutrients
  • Artificially select organisms with a high yield of what you want
  • Reduce competition so that the plant has more energy to create biomass (eg herbicides to kill weeds)
19
Q

How can energy transfer efficiency be increased in animals/livestock

A
  • Reduce respiratory loss by restricting movement and keeping warm in winter
  • Slaughter animals whilst still growing
  • Keep predators away
  • Controlled diet so that higher percentage of food is digested
20
Q

What are the 2 ways that biomass can be measured

A

Dry biomass

Mass of carbon

21
Q

How can dry biomass be measured

A
  • A sample of biomass is warmed until it’s mass remains constant (all water evaporated)
  • Temperature must not be too high to avoid burning
  • Units = Kg m^2
22
Q

How can mass of carbon be measured

A
  • Organisms are made from organic compounds (which contain carbon)
  • So mass of carbon is a good indicator for biomass
  • Carbon is usually about 50% of dry biomass
  • Units Kg m^2 per year
    Per year because some organisms, eg deciduous trees change biomass when leaves drop
23
Q

How can the energy stored in biomass be calculated

A

Calorimetry

24
Q

What is the process of calorimetry

A
  • Burn a sample of biomass completely
  • Heat a known volume of water
  • Measure the temperature change of water
  • Calculate energy released
25
Q

Draw and describe the nitrogen cycle

A

In folder

26
Q

Draw and explain the phosphorus cycle

A

In folder

27
Q

How do microorganisms play a vital role in recycling nutrients such as nitrogen and phosphorus

A

They break down large organic compounds into small inorganic and soluble compounds that can be absorbed by producers

28
Q

What are saprobiants

A

A type of decomposed that digest their food by saprobiontic nutrition

29
Q

What is meant by saprobiontic nutrition

A

Digestion of dead organic matter by extracellular enzymes, products can then be absorbed

30
Q

What are mycorrhizae

A

Fungi that grow in mutualistic relationship with plant roots

31
Q

What are the benefits to a plant of mycorrhizae

A
  • Increase SA of roots so increase absorption of water and minerals
32
Q

What is the benefit to fungi of being Mycorrhizae

A

Exchange of organic compounds eg sucrose from plants

33
Q

Why do fertilisers have to be used for crops

A
  • Crops are harvested so nitrogen and phosphorus are removed from their cycles
  • Soil becomes depleted of these
  • Have to add fertiliser to replace these
34
Q

How can too much fertiliser be harmful

A

Change in water potential to more negative so harder for plants to absorb water

35
Q

What is meant by a natural fertiliser

A

Something the contains nitrogen and phosphorus in organic compounds

36
Q

What are the benefits of using natural fertilisers

A
  • Aerate soil
  • Contain a wider range of elements eg magnesium
  • Consumes less energy
37
Q

What are drawbacks of using natural fertilisers

A
  • Need to be broken down by saprobiants

- Therefore slower release of nitrogen and phosphate ions

38
Q

What are artificial fertilisers

A

Inorganic chemical compounds that counts nitrogen and phosphorus ions

39
Q

What is meant by leaching

A

When soluble compounds are washed off land by rain

This is more common in artificial fertilisers as they are water soluble

40
Q

Describe the process of eutrophication

A
  • Nitrates/phosphate ions leach into fresh water
  • Algal bloom
  • Blocks out light
  • Plants can’t photosynthesise
  • Saprobiants break down dead matter
  • Respire aerobically so use oxygen
  • Fish and other organisms die

Biology Year 2 (10 decks)

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