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Ecology - Coggle Diagram
Ecology
Levels of organisation
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- Food chains always begin with a producer. These are photosynthetic organisms (usually a green plant or algae). They make glucose through photosynthesis. Glucose is used to make other biological molecules in the plant which make up the biomass
- Producers are eaten by primary consumers. Energy is transferred through organisms in an ecosystem when one is eaten by another.
- Primary consumers are eaten by secondary consumers. The animals eaten are called prey and the consumers that kill and eat them are predators
- Secondary consumers are eaten by teriary consumers
- Apex predators are at the top of the food chain
Using a 1x1m quadrat to determine how many clover plants in a field per m^2
- Find the area of the field
- Use a random number generator to work out where to place the quadrats
- Count the number of plants in each quadrat
- Repeat until you have a number of samples from the field (around 10%)
- Divide total number of plants by number of quadrats
How the student could use the mean number of clover plants in a quadrat to estimate the total number in the field:
- find the area of the field in m^2
- area of field x mean number of plants per quadrat
Investigating how the distance from the shoreline impacts number of barnacles growing:
- place a transect on the ground moving from shoreline to inland
- place quadrats at regular intervals down the transect
- count the number of barnacles in each quadrat
- repeat
A stable community will show population cycles between the predators and prey:
If the population of the prey increases, the population of predators will also increase. This will result in the number of prey decreasing after some time because more will be consumed by predators. When there isn't enough prey to feed all of the predators, the predator population will decrease, allowing the prey numbers to increase again.
Abiotic factors
An abiotic factor is a non-living factor, and they can affect the community in many ways
- Light intensity: light is required for photosynthesis. The rate of photosynthesis affects the rate at which the plant grows. Plants are also food sources for other animals
- Temperature: temperature affects the rate of photosynthesis (it increases the rate until it reaches a certain point when the enzymes become denatured)
- Moisture levels: both plants and animals need water to survive
- Soil pH and mineral content: Soil pH affects the rate of decay and therefore how fast mineral ions return to the soil. Different species thrive in different nutrient concentration levels
- Wind intensity and direction: wind affects the rate of transpiration in plants (high wind speed = more transpiration = more water loss).
transpiration affects the temperature of the plant and the rate of photosynthesis because it transports water to the leaves
- Carbon dioxide levels: CO2 affects the rate of photosynthesis in plants. It also affects the distribution of organisms as some thrive in high levels of CO2
- Oxygen levels (in aquatic animals): most fish need a high level of oxygen to survive
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Adaptations
Organisms have adaptations that allow them to survive in the conditions they live in. There are 3 types of adaptations
Structural adaptations: shape or colour of an organism, eg:
sharp teeth of a carnivore to tear meat
camouflage such as the brown colour of a lion coat to avoid prey from spotting them
species in cold environments may have a thick layer of fat for insulation
Behavioural adaptations: the way an organism behaves, eg:
individuals may play dead to avoid predators
basking in the sun to absorb heat
courting behaviour to attract a male
penguins huddling for warmth
zebras gathering in herds for protection
Functional adaptations: involved in processes such as reproduction and metabolism, eg:
late implantation of embryos
conservation of water by producing less sweat
producing less urine
Extremophile live in environments that have extreme conditions. These include areas of high temperatures, pressures, or salt concentrations. An example is bacteria that live in deep sea vents where the pressure is very high.
Adaptations for cooler climates: small surface area to volume ratio to reduce heat loss, lots of insulation (blubber, fat, fur coat etc)
Adaptations for dry climates: adaptations of the kidney that allows the organism to retain lots of water by producing very concentrated urine, being active in the morning/evening when it's cooler, resting in shady areas, large surface area to volume ratio to maximise heat loss
Plant adaptations: curled leaves to reduce water loss, extensive root systems to take in as much water as possible, waxy cuticle to stop water evaporating, water storing tissue in stem
Waste management
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High biodiversity means the ecosystem will be stable. Biodiversity means that species are less dependant on eachother for things such as food and shelter
Humans are having a negative impact on biodiversity, however the future of humans depends on maintaining biodiversity, for example for foods and medicines
As the population increases, more resources are being used and more waste is being produced
More land is being used for houses, farming, shops, roads and factories, which are destroying habitats
Pollution kills animals and plants: sewage, fertilisers and toxic chemicals pollute the water
smoke and acidic gases pollute the air
landfill and toxic chemicals can result in pollution of the land
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Communities
An individual is part of a species, but lives in its habitat within a population
Many different populations interact in the same habitat, creating a community. The populations are often dependant on eachother
An ecosystem is the interaction between biotic and abiotic parts of the environment. Organisms are adapted to live in the conditions of their environment
Organisms that need the same resources must compete for it:
Animals may compete for space, food, terretory and mating partners.
Plants may compete for light, space, water and mineral ions
Interdependence: organisms in a community often depend on other organisms for essentials. Examples include food, shelter, seed dispersal and pollination (flowers are pollinated by bees, birds take shelter in trees etc)
Removing or adding a species to the community can affect the populations of others greatly, as it changes the prey or predator numbers
Stable community: where all the biotic and abiotic factors are in balance, so: the population sizes remain roughly constant
Decomposition
Factors that affect the rate of decomposition:
- Temperature: chemical reactions work faster in higher temperatures, but if it gets too hot, the enzymes denature and decomposition stops
- Water: microorganisms grow faster in conditions with water as it is needed in respiration. water makes food easier to digest.
- Oxygen availability: most decomposers respire aerobically
Compost: when biological material decays, it forms compost. It is then used by gardeners and farmers as a natural fertiliser.
Gardeners have to provide optimum conditions for decay: more oxygen available for aerobic respiration to produce heat, and increased temperatures that increase decay rate to produce compost quicker
Methane gas: microorganisms decompose waste anaerobically to produce methane gas, which can be burnt as a fuel
Biogas generators are used to produce methane. They require a constant temperature of around 30 degrees so the microorganisms keep respiring. It cannot be stored as liquid, so must be used immediately
Required practical
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- make a solution of milk and phenolphthalein indicator
- add sodium carbonate, this will cause the solution to become alkaline and appear pink
- place the tube in a waterbath at a specific temperature
- add the lipase enzyme and begin the stopwatch
- time how long it takes for the pink colour to disappear (when the pH has decreased)
- repeat this at different temperatures to see at which temperatuer the pink disappears the fastest (indicating the quickest rate of decomposition)
Global Warming
Low lying areas will be flooded, reducing habitats
Maintaining biodiversity
Positive human interactions with ecosystems: maintaining rainforests to ensure that habitats are not destroyed
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Negative human interactions with ecosystems: production of greenhouse gases leading to global warming
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Protection of rare habitats: to stop the species here from going extinct, if they get damaged, they may be regenerated to encourage populations to live here
Reintroduction of hedgerows and field margains around land where only one type of crop is grown: maintains biodiversity as the hedgerow provides as habitat for lots of organisms and field margins provide areas where wild flowers/grasses can grow
Reduction of deforestation and carbon dioxide production: reduces the rate of global warming, slowing down the rate that habitats are destroyed
Recycling rather than dumping waste in landfill: reduces the amount of land taken up for landfills and slows the rate that we are using natural resources at
The term global warming refers to the fact that the temperature of the world is increasing. This is because we are producing more greenhouse gases (carbon dioxide, methane etc), resulting in more heat being absorbed and reflected back to earth, heating it
Global warming can cause ice caps to melt, reducing habitats and causing sea levels to rise
Temperature and rainfall levels will affect migration and the distribution of different species, and they may no longer be able to survive where they live
Organisms may become extinct as their habitat is lost, reducing biodiversity
Biotic factors
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- Food availability: more food means more organisms can breed successfully and the population can increase in numbers
- New predators: can cause a decline in the number of prey and take the community out of balance
- New pathogens: when a new pathogen arises, the population has no resistance so they can be wiped out easily
- Competition: if one species is better adapted to the environment than another, then it will outcompete it until the number of lesser adapted species are insufficient to breed
How materials are cycled
The Carbon cycle
- CO2 is removed from the atmosphere by green plants and algae photosynthesising
- The carbon gets moved up the food chain when plants are eaten by animals, who produce CO2 during respiration
- When the plants and animals die, decomposers and detritivores break down the dead organisms. As they do this, they respire which also adds CO2 to the atmosphere
- If the conditions are not right for decay, dead plants and animals can fossilise into fossil fuels (coal, gas, natural oil)
- These fossil fueles are burnt in the process of combustion, which adds CO2 into the atmosphere
The Water cycle
- The suns energy causes water from the surfcae of the earth to evaporate, forming water vapour
The Decay cycle
- When plants and animals die, they get decomposed by decomposers (bacteria, detritivores, fungi)
- The decomposers respire, which puts CO2 back into the atmosphere. They also cycle mineral ions back into plants
- These plants get eaten by animals
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- The animals faeces and urine get decomposed by decomposers and the cycle begins again
Trophic levels
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Tropic level 1: primary producers such as green plants or algae. They make their own food by photosynthesis
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Tropic level 4: tertiary consumers (apex predators). They are carnivores that eat other carnivores but they have no predators
Decomposers break down dead plant and animal matter. They do this by secreting enzymes. The matter is broken down into small soluble food molecules and moved into microorganisms by diffusion
Transfer of biomass
Pyramids of biomass show the relative biomass at each trophic level. It shows the relative weights of material at each level. There is less biomass as you move up the trophic levels
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Only about 10% of biomass is transferred from each trophic level to the next. The remaining 90% is used by the trophic level to complete life processes
Not all biomass can be eaten: carnivores cannot generally eat bones, teeth, hooves, claws etc
Not all biomass eaten is converted into biomass of the animal eating it: some biomass consumed can be lost as faeces, lots of glucose is used in respiration which produces carbon dioxide, in movement, urea is a waste substance which is released in urine
Efficiency of biomass transfer = (biomass in HIGHER trophic level / biomass in LOWER trophic level) x 100
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Sustainable fisheries
The number of fish in the oceans is declining because humans are fishing at a faster rate than populations can regenerate
To avoid species disappearing in certain areas, the population needs to stay above a certain level so breeding can continue
There are limits of net sizes that fishermen can use (making them bigger) so smaller fish are not caught and can reach breeding age to reproduce
Fishing quotas means that only a certain number of a species of fish can be caught in a certain area over a period of time to prevent overfishing
Role of biotechnology
Biotechnology can be used to help feed the population and provide treatment for a number of diseases
Mycoprotein can be made from the bacterium Fusarium. It is grown inside a large fermenter, maintained at optimum conditions
Mycoprotein is a protein-rich food that is suitable for vegetarians (such as quorn). It is grown on glucose syrup in aerobic conditions. The fungus is harvested and purified so it can be consumed.
Proteins without animals reduces land use, as a lot of land is required to rear animals and grow crops to feed them. It also reduces our methane contribution because cows produce methane
Genetically modified bacteria can be used to produce insulin. The insulin is taken and purified and used to treat people with diabetes
Genetically modifying crops to have certain properties can have many advantages: modifying them to be resistant to pests or extreme weather conditions can increase yields. Modifiying them to increase their nutritional value is beneficial in places that are lacking (eg Vitamin A in golden rice)
- As the water vapour rises, it cools and condenses to form clouds
- From the clouds forms precipitation, which returns water to the land by rain, snow, hail etc
- This water can trickle through gaps in the rocks/soil and return to the river/sea (percolation)
Farming techniques
Farmers can aim to increase the amount of energy from fodo that is converted into biomass in livestock because this is more efficient
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Keeping animals in areas with high temperatures so they expend less energy on controlling their body temperature
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This type of farming has many ethical objections because lots of animals are kept in a small place, causing distress. It also increases the risk of a spread of infection. It is used because it increases profit and efficiency, however the standard of living for the animals is very low
