6.5 Ecosystems Flashcards
(76 cards)
1
Q
Ecosystem
A
a community of animals, plants and bacteria interrelated with the physical and chemical environment/ group of living and non living things and their interrelationships
2
Q
Components of ecosystem
A
Habitat, population, community, niche
3
Q
Habitat
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Where an organism lives
4
Q
Population
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all of the organisms of one species who live in the same place at the same time and can breed together
5
Q
Community
A
all the population of different species who live in the same place at the same time and can interact with each other
6
Q
Niche
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role of a specie/organism in an ecosystem = so specific that more than 2 species niche can’t overlap = one would outcompete the other if they came close to occupying the same niche
7
Q
2 important factors in an ecosystem
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Abiotic and biotic
8
Q
Biotic is the…
A
Living factors
9
Q
Biotic factors
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- Competition
- Diseases
- Predation
- Consumers
- Decomposers
10
Q
Abiotic is the…
A
Non living factors
11
Q
Abiotic factors
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- pH
- Temperature
- Humidity
- Weather
12
Q
What should biotic and abiotic factors be like
A
Survival happens when there’s a good mixture of biotic and abiotic factors
13
Q
What word would you use to describe ecosystems and why
A
Dynamic = constantly changing
14
Q
2 main types of changes in ecosystems
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Cyclic changes and unpredictable changes
15
Q
Cyclic changes
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change that repeats itself e.g. seasons and predator prey relationship = organisms can adapt to these changes e.g. hibernating in winter
16
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Unpredictable changes
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E.g. natural disasters
17
Q
Biomass
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Talking about energy
18
Q
What is biomass transferred between
A
Trophic levels (energy levels)
19
Q
Energy transfer diagram
A
20
Q
Trophic levels
A
Producer
Primary consumer
Secondary consumer
Tertiary consumer
21
Q
Producer
A
organism that can photosynthesise and produce organic molecules from water, co2, sunlight
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Q
Primary consumer
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Consumes producer
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Q
Secondary consumer
A
Consumes primary consumer
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Tertiary consumer
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Usually ends w this because there’s no energy to transfer beyond this
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What happens to heat energy through the ecosystem
released (lost as you go through energy levels through processes like respiration
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Energy lost through the ecosystem through:
- heat energy
- Dead organisms and waste materials = further decomposed by bacteria and fungi which also release heat
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Pyramid of numbers
The higher you go up the pyramid, the lower the number of organisms due to the energy loss
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Why do we not rlly use pyramid of numbers
isn’t true reflection of the biomass, so pyramid of biomass is created (each bar is proportionate to the dry mass of the organism at each trophic level)
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Which is better to look at: dry mass or wet mass and why
Dry mass is better than wet mass because it’s a true reflection of the organisms biomass as the wet mass can vary and be a reflection of water intake rather than biomass
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Ecological efficiency equation
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How to increase efficiency
By manipulating the transfer of biomass because productivity = rate of production of new biomass by producers
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Two types of productivity
Gross primary productivity, net primary productivity
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Gross primary productivity
rate at which plants convert light energy to chemical energy - rate of photosynthesis
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Net primary productivity
how much of the chemical energy is transferred in the biomass - proportion of energy from the sun that has entered the food chain
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How do you increase primary productivity
By manipulating the system to increase transfer
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Ways to manipulate the system to increase transfer
- adjust the limiting factors from a reaction:
- Light levels (if limiting rate of photosynthesis - plant the crops early to allow a longer growing season or use light banks where the light are turned on 24/7)
- Water levels (have drought resistant strains)
- Temperature (grow the plants in greenhouses or plant crops early to allow a longer growing season = can miss winter/certain weather periods)
- Nutrients (crop rotation = soil would keep on being fertile)
- Pests (use pesticides or pest resistant breeds)
- Fungal diseases (use fungicides)
- Competition from weeds for light and nutrients (use herbicides)
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Hiw to increase secondary productivity
for primary consumers to consume as much of the plants as possible
Manipulate system to increase transfer
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Why is transfer not good in the first place
- Some plants die
- Some parts of the plants can’t be digested so Egestion through their faeces occurs
- Even when food is consumed, lots is respired and only a little amount is left for the transfer
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How to manipulate the system to increase transfer (increase secondary productivity)
- harvest the animal before adulthood because lots of energy is used to grow into adults, so harvest right before that to reduce energy loss
- Use selective breeding to produce improved growth rate e.g. egg production and growth production
- Antibiotics to animals to avoid loss of energy to pathogens
- Use zero grazing policy = put animals in containers = more energy allocated to growth and muscle rather than finding food
- Transfer energy from producers to consumers is inefficient, therefore grains can be used to feed humans directly and there’s locations in the world where grains can’t be grown, but animals can survive
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Issue w some factors used to increase transfer
Some of these factors aren’t ethical, so there must be a balance between the welfare of the animals and efficient food production.
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Steps of the nitrogen cycle
Nitrification
Ammonification
Denitrification
Nitrogen fixation
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Nitrification
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Ammonification
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Denitrification
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Nitrogen fixation
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Nitrogen cycle diagram
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Saprotrophs
decomposing bacteria and fungi
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What do the bacteria produce
enzymes which digest molecules into smaller molecules which are then reabsorbed by the organism and can be stored and respired.
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How else can nitrogen fixation occur
by the haber process or lightning = only accounts for 10% of all nitrogen fixation
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What’s nitrogen needed for
Protein synthesis
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Azobacter
Free living in the soil
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Rhizobium
lives in root nodules of legumes plants e.g. peas, beans
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What’s rhizobium’s relationship w plants like
mutualistic relationship with the plant so the bacteria provides the plant with nitrogen and receives carbon in return
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How has rhizobium developed this relationship w plants
- adapted this function because it contains a protein called leghaemoglobin = absorbs oxygen and keeps the conditions anaerobic = when the conditions are anaerobic, bacteria uses the enzyme nitrogen reductase to convert nitrogen into ammonium ions
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Ammonification done by nitrosomonas bacteria
Chemoautotrophic
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Nitrobacter
goes from nitrites to nitrates = nitrification = done through oxidation = needs to have aerobic conditions
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Decomposers
feed on dead organic matters and turn them into inorganic matter. Saprophytic (feed on dead organic matter). Secrete enzymes out of their body to digest food = external digestion. Absorb digested food into their body by diffusion
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Detritivores
feed on dead organic matters and turn them into inorganic matter. Internal digestion. Eat food and increase surface area of food they’re digesting to speed up the process of decomposition
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Carbon cycle diagram
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Succession
progressive change in a community overtime
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What do you need for succession to begin
need pioneer species to reach the land
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Examples of pioneer species
Algae and lichens
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Why can pioneer species survive in these conditions
adapted to work in poor conditions and tolerate extreme conditions e.g. salty water, lack of fresh water
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What do pioneer species do
start producing dead organic materials + other processes occur e.g. erosion of rocks, end up producing soil which allows larger plants e.g. mosses to grow = replace the pioneer species
Larger plants are replaced by smaller plants
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What does succession end in
A climax community
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Overview of succession
1. Pioneer species colonise area
2. Natural events e.g. rock erosion or wind blowing which creates more fertile soil + accumulation of nutrients = replaces pioneer species with new sets of species = add nutrients + those species are replaced as the nutrient levels build up
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Primary succession
initial progressive change that occurs in a community of organisms overtime = directional, gradual change
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Pioneer community
species that initially come in and colonise the area = adapted to live in harsher conditions
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Climax community
final, stable community that exists after succession has finished
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Deflected succession
succession is stopped/interfered w due to human interventions = results in a sub-climax community
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Deflected succession is caused by:
- cutting grass
- Cutting down trees
- Building dams
- Burning land
- Use of fertilisers and herbicides
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Distribution
Presence or absence
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Abundance
Number of each specie
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Quadrats
same as module 4 = systematic or random sampling can be used = to know how many samples to take, make a cumulative frequency table, look at species distribution and take a sample = measure how many new species are being found through every quadrat. Eventually you’ll find that you aren’t finding new species when you lay the quadrat down, so you stop taking samples.
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Transects
good to look for gradients = line (just tape) and belt (use tape w quadrat) transects
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Best way to check for distribution across a distance
Kite diagram
