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A Level: Biology > Ecosystems > Flashcards

Ecosystems Flashcards

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1
Q

Define ecosystem

A

A physical area that Includes all living organisms and non living components and there interactions with each other

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2
Q

Define population

A

A group of organisms of the same species living in the same area at the same time and can breed together

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3
Q

Define community

A

Populations of different species living together in the same area area and can interact

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4
Q

Define habitat

A

A place where an organism lives

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5
Q

Define niche

A

The role of an organism in its environment includes what it eats, habitat, competition

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6
Q

Define species

A

A group of similar organisms that can interbreed to produce fertile offspring

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7
Q

Define ecology

A

The study of interactions between living organisms and their environment

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8
Q

Define biotic factors

A

Living factors of an ecosystem

Disease, predation, competition

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9
Q

Define abiotic factors

A

Non living factors

Temp, ph, light intensity, wind velocity

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10
Q

What does it mean if an ecosystem is dynamic

A

It means they are constantly changing

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11
Q

What is competition exclusion principle

A

When an organism shares the same niche and they outcompete each other

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12
Q

State and describe three types of ecological interaction that occur between different species in a habitat

Give an example of each

A 
-interspecific competition 
Grey and red squirrels 
- predator-prey interaction 
Lynx and hare 
-mutualism- both partners benefit 
Crocodile and Egyptian plover bird
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13
Q

Describe mutualism

A

Where both partners benefit

Crocodile lies with its mouth open and Egyptian plover flies into the mouth and eats the decaying meat stuck in the teeth

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14
Q

Why is only 2% of the suns energy used by producers

A

90% reflected by leaf

Only some light wavelengths is used by chlorophyll in plants , most is transmitted

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15
Q

3 reasons why energy is lost at each trophics level

A
  • heat during respiration
  • movement contraction
  • faeces/ indigestible material
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16
Q

Define the term producer

A

An organism that converts light energy into chemical energy through photosynthesis

Starts the food chain

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17
Q

Define consumer

A

Organisms that obtain energy by feeding on other organisms

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18
Q

What is a trophic level

A

Each stage of a food chain

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19
Q

Describe a pyramid of numbers

A

Shows the numbers of the different organisms

Producers always at the bottom
Does not account for the size of organism
Caution- parasites have small sizes and large reproductive cycles

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20
Q

What is biomass

A

Dry mass

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21
Q

What are the measurements for biomass

A

gym^-2

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22
Q

What’s a disadvantage of a pyramid of biomass

A

They are difficult to get data for and organisms must be killed to

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23
Q

Explain the process of finding biomass

A

Takes organism from environment and remove the soil

Dry in a oven at 105°c to evaporate water

Weigh until the mass remains the same

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24
Q

What is the most accurate pyramid

A

Pyramid of energy

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25
Q

What is the units used in a pyramid of energy

A

kJm^-2 year^-1

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26
Q

What is the process of finding energy in a pyramid of energy

A

Takes organism from environment and remove soil

Dry in oven at 105° to evaporate water

Weigh until mass remains the same

Burn in O2 and record temp rise of fixed volume of water using a calorimeter

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27
Q

What percentage of the suns energy is used by producers

A

2%

28
Q

Why is the percentage of suns energy so low

A

90% reflected by leaf
Only some light wavelengths used by chlorophyll
Only some is absorbed most is transmitted
I’m

29
Q

What is the job of decomposed and detritivores

A

They break down organic molecules (proteins, carbohydrates) into inorganic molecules (CO2, nitrate and phosphate)

30
Q

Define gross primary production

A

The total solar energy that is converted into organic matter in producers

31
Q

Define net production

A

What’s left of the gross production after respiration has occurred

32
Q

What’s the formula for % efficiency

A

(Energy after transfer / energy before transfer) x 100

33
Q

What is the formula for net production

A

Gross production - respiratory loss

34
Q

How can a plants net production be lowered

How can this be monitored

A
  • eaten by pests- pesticides
  • leaves fall off- shelter from wind
  • not enough water-irrigation
  • not enough light- use artificial light
35
Q

How could photosynthesis be controlled

A

Light wave lengths can be controlled if dark

Temperature controlled by heaters and ventilation

C02 controlled by burning fossil fuels

36
Q

How may productivity of livestock be increased

A
  • prevent predators eating them- keep them fence in
  • killed by disease- give them vaccinations
  • high protein diets
  • restrict movement (avoid energy loss)
37
Q

Define decomposition

A

The chemical process where larger organic molecules are broken down into smaller inorganic molecules

38
Q

What are decomposers

And what do they do

A

Organisms that feed on and break down plant or animal matter

They turn organic molecules into inorganic molecules

39
Q

What are saprotrophs

What do they do

A

Obtain energy from dead or waste organic material

Extracellular digestion which means enzymes are secreted outside the cells

40
Q

What are detritivores

A

Organisms that feed on dead and decaying material

They break it down into smaller pieces of organic material

These increase surface area for decompsoers

Speed up the rate of decomposition

Perform internal digestion

41
Q

Describe the carbon cycle

A

Carbon compounds in producers➡️carbon in primary consumers➡️ carbon in secondary consumers➡️decomposers

Burn fossil fuels

Decomposers and fossil fuels both release CO2 into air and oceans

42
Q

What’s the formula for photosynthesis

A

Carbon dioxide n water= oxygen n glucose

43
Q

Describe carbon levels during the day and night

A

During day- less CO2 lots of photosynthesis

Night- more CO2 no photosynthesis

44
Q

Which biological molecules contain nitrogen

A

Amino acids

Proteins

DNA

RNA

ATP

45
Q

What makes nitrogen difficult to break

A

It is a triple bond

46
Q

What percentage of nitrogen is in the air

A

78%

47
Q

Describe Azobacter

A

Free living nitrogen fixing bacteria living in the soil

Convert nitrogen in the air into ammonium ions using nitrogen add enzyme in the bacteria

48
Q

Describe Rhizobium

A

Nitrogen fixing bacteria that live in root modules of leguminous plants like peas and clover

It’s a mutualistic symbiotic relationship, plants gain amino acids and rhizobium gain glucose from plants from respiration

49
Q

What does symbiotic mean

A

Live close to each other

50
Q

Describe nitrification

A

An oxidation reaction

Nitrosomonas bacteria oxidise ammonium compounds into nitrites

Nitro after oxidise nitrites into nitrates

Nitrates are highly soluble and are the form in which more nitrogen enters a plant

51
Q

Describe non living nitrogen fixation

A

Lightning- electrical energy in lightning combines nitrogen and oxygen in the air to produce nitrites and nitrates

52
Q

What do denitrifying bacteria do

A

Convert nitrates back into nitrogen gas

Happens in anaerobic conditions in waterlogged soils

53
Q

What process do decomposers do

A

Ammonification

54
Q

What does succession occur as a result as

A

Changes in the abiotic factors of an environment

Caused by decomposition of current species making environment suitable for new species

Other species inter specifically outcompete earlier species and the process repeats until a climax community is formed

55
Q

What is primary succession

A

Starts with the bare rock or sand
There is no soil or organic material present to begin with

This could occur after a volcanic eruption when all soil and dead matter has been destroyed

56
Q

Explain secondary succession

A

Starts with a thin layer of soil such as in a forest clearing after a fire or flood

57
Q

What’s is the technical term for the states of succession

A

Seral stages

58
Q

Name two examples of pioneer species

Name two properties

A

Lichens and mosses

Can photosynthesis to produce their own food

Can cope with extreme abiotic conditions

59
Q

How do pioneer species arrive

A

As spores or seeds carried by winds from nearby land masses or from droppings of birds

60
Q

What is humus

A

Dark organic material that forms in the soil when plant and animal matter decays

Contains many useful elements for healthy soil

61
Q

How do secondary colonisers arrive

Give an example

A

As spores and seeds

Mosses

62
Q

Give an example of a tertiary coloniser

A

Ferns or grasses

63
Q

What is scrubland

A

Small trees and shrubs with many deep roots now take over

This changes in abiotic factors and they out compete the earlier species

64
Q

What does a climax community consist of

A

Consist of animals and plants that have displaced earlier species

Succession is now stopped, there are a few dominant species

65
Q

What is animal succession

A

As the plant species change more habitats and food for consumers are created

66
Q

What is deflected succession

A

Where succession is halted

67
Q

Describe an example of deflected succession

A

Grouse- we burn the heather to prevent it reaching climax community, grouse shooters lay for heather to be burnt so they can shoot the grouse that depend on the heather

If we didn’t do this, pine and birch would outcompete heather and the grouse would be displaced

A Level: Biology (18 decks)

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