Brainscape's Knowledge GenomeTM

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


See full index

Ocr a biology final exam > Chapter 23- Ecosystems > Flashcards

Chapter 23- Ecosystems Flashcards

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

Define an ecosytem

A

Is made up of all the living organisms that interact with one another in a defined 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
2
Q

Biotic factors that affect an echo stem

A

The living factors. For example, in a forest ecosystem, the presence of shrews and hedgehogs are biotic factors, as is the size of their populations- the competition between these two animal populations for a food source is also a biotic factor

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

Abiotic factors affecting ecosystem

A

The non living factors.

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

Abiotic factors

A 
Light
Temperature 
Water availability
Oxygen availability 
Edaphic soil factors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Biotic factors

A

Food
Space
Breeding partners

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

How to calculate efficiency

A

Biomass transferred/biomass intake x100

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

Trophic levels

A

Produce

Consumers

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

Define biomass

A

Is the mass of living material present in a particular place or in particular organisms

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

How to measure biomass

A

Measure mass of fresh material present
Organisms killed
Then heated to 80 degrees until all water has been evaporated- this point is indicated by two identical mass readings

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

How to calculate net production

A

Gross production- respiratory losses

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

Human activities that can affect biomass

A

Shorten the food changing meaning minimum energy is lost since there are fewer tropic levels present.

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

Role of decomposers

A

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

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

What are decomposers an example of

A

Saprotrophs because they obtain their energy from dead or waste organic material.

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

Nitrogen fixation

A

Bacteria such as rhizobium and azotobacter contain the enzyme nitrogenase, which combines with atmospheric nitrogen with hydrogen to produce ammonia. A form of nitrogen that can be absorbed and used by the plants

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

Where do the nitrogen fixing bacteria live

A

Inside root nodules

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

Mutualistic relationship between plant and bacteria

A

Plant gains amino acids

Bacteria gains carbohydrates

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

Nitrification

A

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

18
Q

Two steps of nitrification

A
  1. Nitrifying bacteria (such as nitrosomonas) oxidise ammonium compounds to NO2-
  2. Nitrobacter oxidise nitrites to NO3- nitrates
19
Q

Denitrification

A

In the absence of oxygen, denitrifying bacteria converts nitrates in the soil back to nitrogen gas. Only happens under anaerobic conditions
NO3- to N2
Bacteria use the nitrates as a source of energy for respiration

20
Q

Ammonifcation

A

Is the name given to the process by which decomposers convert nitrogen containing molecules in dead organisms into ammonium compounding

21
Q

Fluctuations of CO2 levels

A

Photosynthesis only occurs during day

Whereas respiration always occurs therefore atmospheric CO2 leves are higher at night

22
Q

Why have CO2 levels increased significantly

A

Combustion of fossil fuels

Deforestation

23
Q

Define succession

A

One proccess by which ecosystems change over time is called succession

24
Q

Define primary succession

A

Occurs on a area of land that has been newly formed or exposed such as bare rock. There is no soil or organic materials present to begin with

25
Q

Define secondary succession

A

This occurs on areas of land where soil is present, but it contains no plant or animal species

26
Q

Where does primary succession occur

A

Volcanoes erupt
Sand is blown by the wind
Slit and mud are deposited at river estuaries
Glaciers retreat

27
Q

What is each stage in succession known as

A

Seral stage

28
Q

Main seral stages

A
  1. Barren land
  2. Pioneer community
  3. Intermediate community
  4. Climax community
29
Q

Pioneer community

A

The first species to arrive usually carried by the wind from nearly by land masses

30
Q

How are pioneer species adapted

A

Able to produce large amounts of seeds or spires
Seeds that germinate fast
Ability to photosynthesise
Tolerance to extreme environments

31
Q

Explain environment in climax community

A

In a stable state
Will show very little change over time
Often not the most biodiversity often mid succession is most diverse

32
Q

Explain deflected succession

A

Human activities can halt the natural flow of succession and prevent the ecosystem from reaching a climax community. When succession is stopped the final stage is known as phagioclimax

33
Q

Why does deflected succession occur

A

Grazing and trampling of vegetation
Removing existing vegetation
Burning

34
Q

Measuring distribution

A

A line or belt transfer is used
A line transect involves laying a line or surveyors tape along the ground and taking samples at regular intervals.
A belt transfer provides more info- two parallel lines are marked, and samples are taken of the area between specified points
They are both forms of systematic sampling

35
Q

Definition of abundance of organisms

A

Refers to the number of individuals of a species present in an area at any given time

36
Q

Measuring plant abundance

A

Use quadrants

Estimated population= number of individuals in sample / area of sample

37
Q

Measuring animal abundance

A
  1. Capture as many individuals in a given area as possible
  2. Mark or tag each individual
  3. Release the marked animals back into area
  4. Recapture as many individuals as possible
  5. Record the number of marked and unmarked individuals caught
  6. Use Lincoln’s index first sample x second sample / number of recaptured individuals
38
Q

Define a producer

A

Convert light energy to chemical energy

39
Q

Define a consumer

A

Which lives and feeds of other animals

40
Q

Define a trophic level

A

A stage in a food web

41
Q

Difference between conservation and preservation

A

Maintains ecosystems with active management

Whereas preservation leaves the ecosystems I disturbed

Ocr a biology final exam (13 decks)

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