Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology Module 6 > 6.3.1 Ecosystems > Flashcards

6.3.1 Ecosystems Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

what is ecology

A

the study of relationships between organisms and their environment

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

what is an ecosystem

A

the living organisms that interact with each other in a defines area, and also the physical factors present in that region

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

what is it meant by ecosystems being dynamic

A

they are constantly changing

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

what are the 2 factors that affect an ecosystem

A

biotic and abiotic factors

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

what are biotic factors

A

the living factors of an ecosystem

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

what are abiotic factors

A

the non-living factors of an ecosystem

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

examples of biotic factors

A
  • often refer to interactions between organisms that are living/once lives
  • often involve competition for:
  • food
  • space
  • breeding partners
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

examples of abiotic factors

A
  • LIGHT INTENSITY: plants need this to photosynthesise, greater the availability, generally the greater the success of the species, and can adapt to different light intensities
  • TEMPERATURE: greatly impacts enzyme controlled metabolic reactions, and plants and endothermic animals (those who control their own internal temperature rather than being effected externally) will develop more rapidly in warmer temps. Changes in temp can trigger migration, hibernation, dormancy and flowering.
    WATER AVAILABILITY: lack of water leads to stress, which can lead to death, and in plants specifically, leaves will wilt (water needed to be turgid) and photosynthesis
    OXYGEN AVAILABILITY: in aquatic ecosystems, cold fast-flowing high O2 water is beneficial, and loss of O2 can lead to suffocation. For plants, water logged soil can reduce availability of O2 for plants
    EDAPHIC (SOIL) FACTORS: different soil types have different particle sizes, which can affect organisms being able to survive in them, e.g. clay (fine and easily waterlogged), loam (different sizes, not waterlogged but retains water) and sandy (coarse, doesn’t retain water and easily eroded)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what do all organisms in an ecosystem require, and where does this originate from for almost all ecosystems

A
  • energy to function and survive
  • light energy from the sun converted to chemical energy in plants and photosynthetic organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the difference between food chains and food webs

A

both show the transfer of biomass (mass of living material) and therefore energy through organisms in an ecosystem
- food web is a system of interlinked food chains

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

what is each stage of a food chain called

A

trophic level

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

what is the first trophic level always

A

a producer:
- organism that converts light energy into chemical energy via photosynthesis

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

what are all trophic levels except for the first one

A

consumers:
- organisms that obtain their energy from feeding on other organisms

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

what is the second trophic level always

A

a primary consumer:
- an animal that eats a producer

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

how are other trophic levels labelled

A

secondary, tertiary and quaternary consumer
(organisms that eat primary, secondary… consumers)
- usually no further than this, as there is not sufficient biomass or stored energy to support any further organisms

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

how can u represent food webs as a pyramid of numbers

A

each level shows the number of organisms at that trophic level, with producers at the bottom

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

what is biomass and why do we measure it

A

the mass of living material present in a particular place or in a particular organism

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

how can you measure biomass

A

multiply the biomass present in each organism by the total number of organisms in that trophic level

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

what information does a pyramid of biomass show

A

the biomass present in that moment of time, does not account for seasonal changes

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

what is the easiest way to measure biomass, but why is it not used

A
  • measure the mass of fresh material present
    BUT
  • water content must be discounted
  • makes the technique unreliable, as there are varying amounts of water in different organisms, so would need a very large sample
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

which technique is usually used to calculate biomass, but why is it problematic

A
  • measuring the “dry mass” of organisms
    BUT
  • means organisms have to be killed to be dried (places in oven until all water has been evaporated)
    SO
  • to minimise the destruction of organisms and animals, a small sample is usually only taken
  • but this might not be representative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

what is biomass measured in

A

g m-2 for land
g m-3 for water

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

what happens to biomass through the trophic levels

A

is is nearly always less than the one below

24
Q

why does biomass decrease as you increase the trophic level

A
  • biomass consists of all cells and tissue of organisms present, including the carbon compounds they contain.
  • as carbon is a store of energy, it can be equated to energy content
  • when animals eat, only small proportion of the food they eat is converted into new raw tissue
  • only this part of biomass is available for next level to eat
25
Q

what is the energy available at each trophic level measured in

A

kJ m-2 yr-1 (kilojoules per metre squares per year)

26
Q

why is biomass energy measured as per year

A

to allow for changes in photosynthetic production and consumer feeding patterns throughout the year to be accounted for

27
Q

what is ecological efficiency

A

the efficiency with which biomass or energy is transferred from one trophic level to the next
- can be presented by a pyramid of energy

28
Q

how much energy do producers convert that they receive

A
  • only convert 1-3% of sunlight that they receive into chemical energy and biomass
29
Q

why do producers convert such little energy into biomass

A
  • not all of solar energy is used for photosynthesis (about 90% is reflected, some transmitted through and some is an unusable wavelength)
  • other factors might limit rate of photosynthesis, like water availability
  • proportion of the energy is lost, as it is used for photosynthetic reactions
30
Q

what is gross production

A

the total solar energy that plants convert to organic matter

  • even this is reduced, as 20-50% is used for respiration
  • remaining energy is converted to biomass, called net production which is available for the next trophic level
31
Q

which formula is used for calculating the net production of biomass

A

net production = gross production - respiratory losses

  • what is available to next trophic level
32
Q

how much energy do consumers convert into biomass

A

at most 10% goes to their own organic tissue

33
Q

why do consumers convert such little biomass

A
  • not all of the biomass of the organisms is eaten, e.g. roots and bones
  • some energy is transferred to the environment as metabolic heat ( due to movement and respiration)
  • some parts are eaten but indigestible, and so are egested as faeces
  • some energy is lost in excretory materials such as urine
34
Q

how much energy does a tertiary consumer have compared to sunlight first present

A

about 0.001%

35
Q

what is the equation for calculating ecological efficiency between each trophic level

A

energy/biomass after transfer DIVIDED BY energy/biomass before transfer x 100

36
Q

how do humans use agriculture to manipulate the environment

A
  • plants we want are provided with abiotic conditions needed to thrive, e.g. water, warmth)
  • competition is removed and so is predators
37
Q

how does agriculture create efficient biomass transfer

A
  • for animals, only 3 trophic levels, of animal feed, livestock and humans
  • for plants, only 2 trophic levels, of crops and humans
  • fewer trophic levels that present naturally means minimum energy is lost, so as much biomass can be eaten by humans
38
Q

what is decomposition

A

a chemical process in which a compound is broken down into smaller molecules, or its constituent elements

39
Q

what is a decomposer

A

an organisms that feeds on and breaks down dead plant or animal matter, thus turning organic compounds into inorganic ones available to photosynthetic producers in the ecosystem

40
Q

give examples of common decomposers

A

microscopic fungi and bacteria, but also larger bacteria such as toadstools and bracket fungi

41
Q

why can decomposers be called saprotrophs

A

they obtain their energy from dead or waste organic material, called saprotrophic nutrition

42
Q

how do decomposers digest their food

A
  • digest their food externally
  • secrete enzymes onto dead organisms or organic waste matter
  • enzymes break down complex organic molecules into simpler soluble molecules
  • decomposers can absorb these molecules
  • through this process, they can also released stored inorganic compounds and elements back into the environment
43
Q

what are detritivores

A
  • another class of organisms involved in decomposition
44
Q

how do detritivores help with decomposition

A
  • speed up decay by feeding on on detritus (dead and decaying material)
  • they break it down into smaller pieces of organic material
  • this increases the surface area for decomposers to work on
  • e.g. woodlice breaking down wood and earthworms breaking down dead leaves
45
Q

what type of digestion do detritivores perform

A

internal digestion

46
Q

what is nitrogen needed for and how is it obtained

A

essential element in amino acids, proteins, and nucleic acids

  • animals can obtain for food, but plants need it from their environment
47
Q

how is nitrogen most abundant, and why is this a problem

A
  • 78% of the air is nitrogen gas
  • this form however CANNOT be taken up by plants
  • must be combined with other elements like O and H
  • bacteria plays a very big role in converting nitrogen into usable sources for plants
48
Q

what are the bacteria involved in nitrogen fixation

A

Azotobacter and Rhizobium

  • both contain enzyme nitrogenase
49
Q

where does azotobacter and

A
50
Q

explain process of nitrogen fixation

A

nitrogenase combines with atmospheric N2 and H2 to produce ammonia NH3
- this is a form of nitrogen that can be absorbed and used by plants

51
Q

what is azotobacter

A

free-living bacterium

52
Q

where do most of the nitrogen-fixing bacteria live, and give an example

A
  • inside root nodules
  • these are growths on the roots of leguminous plants (peas, beans and clover)
53
Q

explain the symbiotic relationship between bacteria and nitrogen fixation

A
  • plant gains amino acids from the Rhizobium, which are produced by fixing nitrogen in the air into ammonium in the bacteria
  • bacteria gains carbohydrates produced by the plant during photosynthesis, which is used as an energy source
54
Q

what is nitrification

A

the process by which ammonium compounds in the soil are converted into nitrogen-containing molecules that can be used by plants

55
Q

what type of bacteria takes part in nitrification

A

free-living bacteria in the soil called nitrifying bacteria

56
Q

what type of reaction is nitrification, and what does this mean

A
  • oxidation reaction
  • needs to take place in well-aerated soil
57
Q

what are the 2 steps of nitrification

A

1) nitrifying bacteria (such as Nitrosomonas) oxidise ammonium compounds into nitrites NO2-

2) other nitrifying bacteria (Nitrobacter) oxidise nitrites into nitrates NO3-

  • NO3- ions are highly soluble, so this is the form that most nitrogen enters a plant

Biology Module 6 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions