Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

biology > Energy And Ecosystems > Flashcards

Energy And Ecosystems Flashcards

1
Q

Define producers

A

Photosynthetic organisms who manufacture organic substances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Define consumers

A

Organisms that gain energy from consuming other organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Define saprobionts

A

Decompose waste and remains of dead organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between food chains and webs

A

Food chains show one organism at each trophic level

Food webs show complex interrelations of many food webs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Pros and cons of food webs

A

Show more realistic consumption as organisms will have more than one food source

Can get very complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define trophic level

A

Stages of food chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do arrows in food chains depict

A

Transfer of energy along chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Define biomass

A

Mass of living material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why is dry material used not fresh

A

Fresh will vary due to water availability

Dry is more accurate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the cons of using dry mass

A

Have to kill organisms so only small sample obtained which is not representative

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the units for biomass

A

Grams per metre squared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe. How to use a calorimeter

A

Weigh the sample and place in cup in chamber

Ignite using ignition wires

Record initial temp

Heat from combustion heats water

Record max temp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What temp is used for calculating dry biomass, why

A

100

Water evaporates and biomass doesn’t burn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When does all the energy in an ecosystem originate and end up

A

From the sun

Ends up are heat energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the major difference between the transfer of energy and nutrients in an ecosystem

A

Nutrients can be recycled

Energy cannot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is only 1% of the sun’s energy transferred by plants

A

Rays reflected back into space via clouds and dust

Not all wavelengths used in Photosynthesis

Other factors are limiting (co2)

Light may not land on a chlorophyll

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How and why can net primary production be used to compare ecosystems

A

Allow comparison between efficiency of energy storage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define net primary production

A

The rate at which plants store energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Define the gross primary production

A

The energy converted into biomass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is there a low percentage of energy between trophic levels

A

Not all of organism is consumed
Some parts can’t be consumed
Energy lost via excretion and movement
Heat energy lost via Respiration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Why is there a higher percentage energy transfer between 2 and 3 trophic levels

A

Carnivores use more of there food than herbivores

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In what instances is energy transfer lower

A

Older animals
Mammals (heat lost to maintain temp)
Primary consumers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the results of inefficient energy transfer

A

Food chains have few trophic levels

Total biomass at higher trophic levels is less

Less energy available for higher trophic levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why do organisms require nitrogen

A

Amino acid, protein and nucleic acid synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What form of nitrogen do plants absorb
Nitrate ions
26
How are nitrates absorbed by plants
Active transport
27
Why do nitrates need regular replenishment
They are leached (because soluble) and used up
28
What are the processes in the nitrogen cycle
Nitrogen fixing Ammonification Nitrification Denitrification
29
Describe nitrogen fixing
Nitrogen gas from atmosphere converted into ammonia
30
In what ways can nitrogen be fixed
Atmospheric (lightning) Industrially Biologically
31
What types of nitrogen fixing bacteria are there
Free living and mutualistic
32
Describe how mutualistic nitrogen fixing bacteria interact with plants
Assimilate ammonia into Amino acids and exchanged for carbohydrates
33
Describe how nitrogen fixing bacteria work
Reduce nitrogen to ammonia Aerobic Respiration
34
Describe the process of Ammonification
Saprobionts convert ammonia to ammonium ions
35
From what does Ammonification take place
Waste and dead material Urea Protein Nucleic acids Vitamins
36
Describe Nitrification
Conversion of ammonium ions to nitrite ions then nitrate ions by aerobic bacteria
37
Describe nitrifying bacteria
Chemotrophs= use chemical to produce food not light Aerobic
38
Describe Denitrification
Conversion of nitrate ions into nitrogen gas by anaerobic denitrifying batería
39
Describe denitrifying bacteria
Anaerobic Use nitrate ions instead of oxygen.
40
Describe denitrifying bacteria
Anaerobic Use nitrate ions instead of oxygen.
41
How can to productivity of soils be improved other than fertilisers
Aerate soils= more oxygen= more nitrification= more nitrate ions More DOM= more Ammonification
42
What forms of nitrogen can plants use
Ammonia | Nitrate ions
43
Describe how saprobionts work
Secrete enzymes for extracellular digestion Macro molecules hydrolysed to micromolecules which diffuse into bacteria Aerobic Respiration
44
In what form is phosphorus found in the phosphorus cycle
Phosphate ions
45
What are the differences between the phosphorus and nitrogen cycle
Phosphorus is never gaseous Nitrogen is fast Phosphorus can be found in skeletons and shells Phosphorus is released from rocks via Weathering
46
What is phosphorus used for
DNA Phospholipids ATP
47
Describe the phosphorus cycle
Phosphates in rock are released due to Weathering and erosion Phosphate ions are in the sea and rivers Absorbed by plants and move along food chain Waste and dead material contain phosphates which are broken down by saprobionts Phosphates released into rivers where they sediment to form rocks
48
Describe the nitrogen cycle
Nitrogen gas is converted into ammonia by nitrogen fixing bacteria Ammonia is absorbed by plants and passed along food chain Waste and dead matter contain ammonia compounds which are converted into ammonium ions via saprobionts Ammonium ions converted into nitrite and then nitrate ions by nitrifying bacteria Nitrates absorbed by plants Denitrifying bacteria convert nitrates into nitrogen gas
49
What microbe is involved in the phosphorus cycle
Mycorrhizae fungi
50
Describe the interaction between the micorrhzae and plants
Fungi grows in and around plant tissue Highly specific to species Coevolution Increase surface area for absorption of water and mineral ions Act like sponge so plant is drought resistant Exchange mineral ions for carbohydrates
51
What type of organism are micorrhzae
Saprobionts
52
Why do we need fertilisers
Intense farming disrupts nutrient cycles depleting soils of nutrients Biomass removed so no decomposition Increases productivity
53
What needs to be ensured for fertilisers to have maximum effect
Applied at right time and right amount
54
What types of fertilizers are there
Natural and artificial
55
What are artificial fertilizers made of
NPK mined from rock deposits
56
What are the benefits of artificial fertilizers
Immediate source of mineral ions Guaranteed composition More concentrated= less needed= cheaper (transport and supply) and less damage done by machines Clean and convenient
57
What are the cons of artificial fertilizers
Leaching and eutrophication Mining causes damage
58
What are natural fertilisers made of
Dead matter and waste Bone meal Urea Manure Compost
59
What are the pros of using natural fertilisers
Lasts longer Longer release May contain important trace elements Improve soil structure (reduced erosion and better at holding water)
60
How do fertilizers increase crop yield
Provide vital mineral ions Converted into Amino acids, lipids and DNA Larger biomass= Larger leaves Large SA for Photosynthesis= more carbohydrates = taller
61
What are the environmental effects of fertilisers
Reduced species diversity Leaching Eutrophication
62
How do fertilizers lead to reduced species diversity
High N conc favours grasses and nettles which outcompete other species
63
Describe leaching
Rainwater dissolves nitrate ions Carries them far down into soil Roots are unable to reach ions Found in rivers and lakes and drinking water
64
Why is leaching bad
Nitrates end up in drinking water Can cause stomach cancer Prevent efficient oxygen transport in babies Eutrophication
65
Describe how eutrophication occurs an dits effects
Nitrates are usually limiting factor in lakes N conc increases, no longer limiting so algal bloom Light doesn't reach lake floor Photosynthesising plants lower down die Less oxygen produced Decomposition increases so more saprobionts Oxygen is limiting for aerobic organisms Aerobic organisms die so less competition between aerobic and anaerobic organisms More decomposition so more nitrates and toxic substances (hydrogen sulphide) = putrid water

biology (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions