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biology year 2 > 5B - energy transfer and nutrient cycles > Flashcards

5B - energy transfer and nutrient cycles Flashcards

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1
Q

What is an ecosystem

A

This is all the organisms living in a particular area and all the abiotic conditions

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2
Q

What is a producer

A

An organism that makes its own food

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3
Q

What do plants use and create in photosynthesis

A

Use energy and co2 to make glucose and other sugars

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4
Q

What is biomass and what is it made up of?

A
  • The mass of living material/Chemical energy stored in the plant
  • Biological molecules made from glucose eg cellulose
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5
Q

What can biomass be measured in terms of :

A
  • The mass of carbon that an organism contains
  • The dry mass of its tissue per unit area
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6
Q

How do you measure dry mass

A
  1. Sample of organism is dried
  2. Weighed at regular intervals
  3. Once mass becomes constant all water has been removed
  4. Scale up result to give biomass of the total pop
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7
Q

How you you estimate the amount of chemical energy stored in biomass

A
  • CALORIMETRY
    1. Burn dry biomass
    2. Energy released is used to heat a known volume of water
    3. Change in temp of water is used to calculate the chemical energy of dry biomass
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8
Q

What is energy measured in

A

Joules
KiloJoules

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9
Q

What is GPP

A

Gross primary production is the total amount of chemical energy converted from light energy by plants in a given area

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10
Q

What is R?

A

This is respiratory loss and is the amount of of GPP lost to the environment as heat when plants respire

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11
Q

What is NPP

A

Net primary production is the remaining chemical energy for growth and reproduction

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12
Q

How do you work out primary production

A

NPP = GPP - R

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13
Q

What are the units for primary production?

A

It is expressed as a rate (total amount of chemical energy in a given area in a given time)
- Kjha^-1yr^-1
- kjm^2yr^-1

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14
Q

How is chemical energy lost

A
  • Not all food is eaten to energy not taken in
  • Some are indigestible so lost as faeces
  • Respiration
  • Urine
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15
Q

What is the Net production?

A

The energy that is left after all this is stored in the consumers biomass

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16
Q

How do you calculate net production

A

N = I - (F+R)
N = net production
I = chemical energy in ingested food
F = Chemical energy lost in faeces and urine
R = Energy lost through respiration

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17
Q

How do you calculate efficiency of energy transfer

A

% efficiency of energy transfer = net production of trophic level / net production of previous trophic level x 100

18
Q

When does energy transfer become more efficient

A

When you move up the food chain as producers contain more indigestible matter than consumers

19
Q

What is a trophic level?

A

The stages in a food chain

20
Q

What are the two ways to increase efficiency?

A

Simplifying food webs
Reducing respiratory losses

21
Q

How does simplifying food webs increase efficiency

A

Using pests to reduce the amount of energy available for crops so less for humans
This gets rid of food chains that dont involve humans so energy losses reduced and NPP of crop increases

22
Q

How does reducing respiratory loss increase efficiency

A
  • Restrict movement of animals movement can increase rate of respiration
    -Keep animals warm so less energy lost by generating body heat
23
Q

What are the 2 things that saprobionts do ?

A
  • Feed on the remains of dead plants and animals and their waste products breaking them down so chemical elements can be recycled
  • Secrete enzymes and digest food externally - EXTRACELLULAR DIGESTION so organic molecules are broken into inorganic ions
24
Q

What is saprobiotic nutrition

A

Obtaining nutrients from dead organic matter and animal waste using extracellular digestion

24
Q

What is a symbiotic relationship

A

Two species live closely together and one or both species depend on each other for survival

25
Q

What is a Mycorrhizae

A

A type of fungi that forms a symbiotic relationship with the roots of a plants
- fungi made up of long thin strands known as Hyphae which connect to the plants roots increasing the SA so they can absorb ions
- Hyphae also increase water uptake in turn the fungi obtain organic compounds such as glucose

26
Q

What contains nitrogen

A

Proteins, Nucleic Acids, Dna, RNA

27
Q

What are the basic stages of the nitrogen cycle

A
  1. Nitrogen Fixation
  2. Ammonification
  3. Nitrification
  4. Denitrification
28
Q

What is the first stage of the nitrogen cycle in detail?

A

Nitrogen fixation
1. Bacteria ( Rhizobium) turn nitrogen into ammonia which goes to form ammonium ions in solution that can be used by plants
2. The Rhizobium are found inside root nodules of leguminous plants forming a mutualistic relationship

29
Q

How does the bacteria form a mutualistic relationship

A

The bacteria provide the plant with nitrogen compounds and the plant provides them with carbohydrates

30
Q

What is the second stage of the nitrogen cycle in detail

A

Ammonification
1. nitrogen compounds from dead organisms are turned into ammonia by saprobionts forming ammonium ions
2. Animal waste such as urine and faeces also contain nitrogen compounds which are turned into ammonium ions

31
Q

What is the 3rd stage of the nitrogen cycle in detail

A

Nitrification
1. Ammonium ions in the soil are changed into nitrogen compounds that can be used by plants –> NITRATES
2. It is first changed into NITRITES and other nitrifying bacteria turn it into NITRATES

32
Q

What is the 4th stage of the nitrogen cycle in detail

A

Denitrification

  1. Nitrates in soil are converted into nitrogen gas by denitrifying bacteria
  2. Happens under anaerobic conditions by using nitrates in soil to carry out resp
33
Q

What compounds contain phosphorus

A

Phospholipids
Dna
Atp

34
Q

Where is phosphorus found

A

Rocks
Dissolved in oceans in the form of phosphate ions

35
Q

What is the stages of the phosphorus cycle

A
  1. Phosphate ions released into soil by weathering
  2. Phosphate ions taken into plants through roots and mycorihizzae increase rate
  3. Ions transferred through food chain
  4. Saprobionts break down the organic compounds when plants and animals die releasing phosphate ions into the soil
  5. Phosphate ions released from urine and faeces
  6. Weathering of rocks are releases phosphate ions into seas, lakes and rivers which is taken up by aquatic producers such as algae
  7. Waste produced by sea birds is known as Guano and contains phosphate ions therefore used as a natural fertiliser
36
Q

How are nutrients lost

A

Harvesting of crops
Animals removed from land

37
Q

What are the different types of fertilisers

A

Artificial - inorganic and contain pure chemicals as powder or pellets
Natural - organic and include manure, composted veg, crop residue

38
Q

What is the environmental issue with Fertilisers

A

Leaching - water soluble compounds in the soil are washed away into ponds and rivers leading to eutrophication

39
Q

What is Eutrophication

A
  1. Mineral ions leached from fertilised fields stimulate rapid growth of algae
  2. The algae block lights reaching surface below
  3. The plants die as unable to photosynthesise
  4. Bacteria feed on dead matter reducing o2 conc by carrying out aerobic resp
  5. Aquatic organisms die as not enough dissolved oxygen

biology year 2 (11 decks)

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