Biology Y13 > Module 6.3.1 - Ecosystems > Flashcards

Module 6.3.1 - Ecosystems Flashcards

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1
Q

What is an ecosystem?

A

All living organisms that interact with one another in defined area and also the physical factors present in that region, abiotic and biotic factors of an area

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2
Q

What are example abiotic factors?

A
  • temperature
  • light
  • pH
    water and humidity
  • oxygen availability
  • soil factors
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3
Q

How does light affect an ecosystem?

A

Greater light intensity = greater rate of photosynthesis, more seeds, increase population, more animals can be supported

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3
Q

How does temperature affect an ecosystem?

A
  • each species has own optimum temp
  • further away from optimum, fewer can survive
  • ectothermic animals can grow faster
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3
Q

How does pH affect an ecosystem?

A
  • high pH will denature enzymes so substrate cant bind
  • species have own optimum pH to survive
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4
Q

How does water and humidity affect an ecosystem?

A
  • only species adapted to dry conditions will increase population
  • increase humidity affect transpiration rates
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5
Q

How does oxygen availability affect an ecosystem?

A
  • aquatic ecosystems benefit from fast flowing, cold water as has more concentration of oxygen
  • waterlogged soil = less oxygen
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6
Q

How does edaphic(soil) factors affect an ecosystem?

A
  • soil provides minerals needed for growth, water for photosynthesis and anchorage for roots
  • different types of soil retain different things
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7
Q

What are the 3 types of soil and what are their properties?

A

Sandy soil: 0-10% clay, 0-10% silt, 80-1005 sand, more air spaces, doesnt retain water as much
Clay soil: 50-100% clay, 0-45% silt, 0-45% sand, fewer air spaces, retains water
Loam soil: 10-30% clay, 30-50% silt, 25-50% sand, ideal amount for farming

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8
Q

What are examples of biotic factors?

A
  • territory
  • food
  • competition
  • breeding partners
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9
Q

What is a producer?

A
  • makes biomass
  • start of food chain
  • autotrophic
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10
Q

What is a carnivore?

A

eats other organisms/meat

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11
Q

What is a herbivore?

A

eats plants

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12
Q

What is an omnivore?

A

eat all kinds of biomass

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13
Q

What is a primary consumer?

A
  • eats producers
  • typically herbivores
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14
Q

What is a secondary consumer?

A
  • consume primary consumers
  • typically omnivores and carnivores
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15
Q

What is a trophic level?

A

Where an organism is within the food chain

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16
Q

What does a pyramid of numbers and pyramid of biomass do?

A

Pyramid of numbers - how many organisms support each other
Pyramids of biomass - amount of energy/biomass organisms have

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17
Q

What is biomass?

A

Mass of living material present in particular place or in particular organisms

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18
Q

How do you measure biomass?

A

Biomass in each organism x number of organisms in trophic level

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19
Q

What are the 2 ways to measure biomass?

A

Mass of fresh material present - easiest, unreliable as mass of water varies greatly

Dry mass - more accurate, organisms are killed and put in an oven at 80 degrees, evaporates water

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20
Q

What are the units for areas of land and water?

A

Land - g/m^2
Water - g/m^3

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21
Q

What is ecological efficiency?

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A

Efficiency with which biomass or energy transferred from 1 trophic level to the next

22
Q

What is the efficiency of producers?

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A
  • can only convert 1-3% of sunlight into chemical energy
  • energy is lost in photosynthetic reactions
23
Why is the nitrogen cycle necessary?
- energy from the sun is limitless - energy from sun is the source for nearly all ecosystems - is finite so must be recycled
23
What are the 6 main parts of the nitrogen cycle?
- decomposition - nitrogen fixation - ammonification - nitrification 1 - nitrification 2 - denitrification
23
How can you calculate net production?
Net production = gross production - respiratory losses
24
What is decomposition?
A chemical process of compounds being broken down into constituent molecules
25
What do decomposers and detritivores do?
Decomposers - feed on/break down dead matter, convert organic compounds into inorganic compounds, saprophytic Detritivores -speed up decaying process, feed on dead material, break down dead matter onto small pieces which increases SA for decomposers
26
What is nitrogen fixation?
Nitrogen gas -> nitrogen containing compounds
27
what is Azotobacter and mutualistic bacteria?
Azotobacter/Rhizobium - free living, make amino acids, release them when they die, contain nitrogenase enzyme to convert nitrogen and hydrogen into ammonia Mutualistic bacteria - live in root nodules in peas and beans, obtain carbohydrates from plants and it gets amino acids from bacteria
28
What is ammonification?
The production of ammonia from organic compounds (e.g. urea, proteins, nucleic acids) - saprophytic microorganisms release ammonia into soil
29
What happens during nitrogen 1?
- nitrifying bacteria oxidise ammonium compounds - ammonium ions > nitrite ions (NO2-) - oxidation reaction, aerated soil required
30
What happens during nitrogen 2?
- nitrite ions > nitrate ions (NO3-) - requires oxygen - nitrobacteria do this
31
What is denitrification?
Occurs when soil becomes waterlogged - O2 shortage - anaerobic bacteria carry out denitrification as don't need O2 - reduced nitrogen compounds available to plants
32
What percentage of the earth's atmosphere is CO2?
0.04%
33
What process removes CO2 from the atmosphere?
photosynthesis
33
What process puts CO2 back into the atmosphere?
- respiration - combustion - decomposition
33
Why are CO2 levels higher at night?
Plants dont photosynthesise at night as stomata are closed so more CO2 is in the atmosphere
34
Why have CO2 levels increased over the past hundreds?
- deforestation - increased fossil fuel burning
35
What do the seas do for CO2?
The seas are carbon sinks as carbon dissolves in the sea, but less is dissolved at high temps - example of positive feedback
36
36
What is the greenhouse effect?
- heat from sun is reflected from earth's surface - when it reaches atmosphere, some rays pass through - other rays are trapped in by greenhouse gases
37
How is methane produced?
- when decomposers break down dead remains and microbes in primary consumers digest food thats been eaten - cattle - more decaying waste
38
What are the consequences of global warming?
- sea levels rising from melting of the ice caps, causes flooding - changes in temperature and precipitation - failed crops - increased extreme weather - natural plant distribution - loss of species
39
What is succession?
Process of ecosystems changing over time
39
What is a community?
All populations of different species living and interacting together in particular area
40
What are features of a Pioneer species?
- produce large quantities of easily dispersible seeds/spores - ability to fix nitrogen - withstand extreme conditions - ability to photosynthesis - rapid germination - e.g. algae, marram grass, lichen
41
What are Pioneer features of marram grass?0
- deep roots - tolerates salty environments - highly adapted to be pioneer species
42
What is primary succession?
Starts out from bare rock that in inhabitable and over hundreds of years, evolves into a climax community,
43
What is secondary succession?
A disturbance to the ecosystem occurs and the environment has to rebuild itself but only over a few years
44
What is each stage called in primary and secondary succession?
A seral stage
45
What is animal succession?
- takes linger as have to migrate compared to plants which get blown - more complex
46
What is deflected succession?
- community remains stable because of human activity - prevents further succession running its course - happens from grazing or mowing grass - many places need to be actively managed to battle succession
47
What is plagioclimax community?
When a community is artificially managed
Biology Y13
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