Ecosystems And Material Cycles Flashcards
Interdependence definition
Organisms depend on each other for things like food and shelter in order to survive and reproduce £ means that a change in the population of one species can have a huge knock on effect for other species in the same community
What is mutualism
A relationship between 2 organisms from which both organisms benefit e.g. bees and flowering plants
What is parasitism
parasitism, relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism.
What does abiotic mean
Non living
What does biotic mean
Living
What are 4 abiotic factors that affect communities
Temperature, amount of water, light intensity, levels of pollutants
What are 2 biotic factors that affect community
Competition, predation
What is a quadrat
A square frame enclosing a known area
Steps on how to use a quadrat to study the distribution of small organisms
1) place a 1m(2) quadrat on the ground at a random point within the first sample area - could use a random number generator to make up coordinates of where to place the quadrat
2) count all the organisms you’re interested in within the quadrat
3) repeat steps 1-2 lots of times
4) work out the mean number of organisms per quadrat within the first sample area
5) repeat steps 1-4 in the 2nd sample area
6) compare the 2 means
What is a gradient
When abiotic factors change across a habitat
What is a belt transect
Quadrat laid out along a line
What are the steps to using a belt transect to study distribution along a gradient
1) mark out a line in the area u want to study
2) collect data along the line using quadrats placed next to each other - collect data by counting all the organisms of the species or by estimating percentage cover - estimating the percentage area of a quadrat covered by a particular type of organism
3) u could also record other abiotic factors in each quadrat
4) repeat steps 1 and 2 several times then find the mean number of organisms or mean percentage cover for each quadrat
5) plot graphs to see if the changing abiotic factor is correlated with a change in the distribution of the species you’re studying
What are 3 negative human interactions with ecosystems
Eutrophication, fish farming, introduction of non indigenous spices
Why is eutrophication a negative human interaction with ecosystems
When nitrates are put onto fields as fertilisers, if too much fertiliser is applied and it rains after, the nitrates find their way into lakes and rivers - eutrophication which can lead to the death of many species in the water reducing biodiversity of the habitat
Steps of how fish farming is a negative human interaction with ecosystems
1) food is added to the nets to feed fish - producing huge amounts of waste and the waste can leak into the open water causing eutrophication and the death of wild species
2) fish farms in open water often act as a breeding ground for large numbers of parasites - which can get out and infect wild animals and kill them
3) predators (e.g. sea lions) are attracted to the nets and can become trapped in them and die
4) sometimes farmed fish can escape into the wild which can cause problems for wild populations of indigenous species
Why does the introduction of non indigenous species negatively impact biodiversity
Some non indigenous species compete with indigenous species for resources like food and shelter sometimes they are better at getting these things and out-compete the indigenous species which increase in number and eventually die out
Some non indigenous species also bring new diseases to a habitat infecting and killing lots of indigenous species - reducing biodiversity in that habitat
What are 2 ways human interaction can help conserve and maintain biodiversity
Reforestation, conservation schemes
How does reforestation help
Deforestation reduces biodiversity as many species use trees to provide food and shelter and planting new trees help give species new places to live
What are the conservation methods
Protecting a species’ natural habitat - so that they have a place to live, protecting species in safe areas outside of their natural habitat - animals protected in zoos and introducing captive breeding programmes to increase numbers, use of seed banks to store and distribute the seeds of rare and endangered plants
What are the 6 benefits of maintaining diversity
Protecting the human food supply, ensuring minimal damage to food chains, providing future medicines, cultural aspects, ecotourism, providing new jobs
How are materials recycled through biotic and abiotic components of ecosystems
1) living things are made of elements they take from the environment e.g. plants take in carbon and oxygen from the air and nitrogen from soil
2) they turn these elements into the complex compounds (carbs, proteins, fats) that make up living organisms. Elements are passed along food chains when animals eat the plants and each other
3) the elements are recycled - waste products and dead organisms are broken down by decomposers (usually microorganisms) and the elements in them are returned to the soil or air, ready to be taken in by new plants and put back into the food chain
Important points about the carbon cycle
1) only one arrow going down from co2 in the air. The whole thing is powered by photosynthesis. Green plants use the carbon from co2 to make carbs, fats, proteins
2) eating passes the carbon compounds in the plant onto animals in a food chain.
3) both plant and animal respiration while the organisms are alive releases co2 back into air
4) plants and animals eventually die and decompose or are killed and turned into useful products
5) when plants and animals decompose they’re broken down by microorganisms such as bacteria and fungi. These decomposers released co2 back into air by respiration as they break down the material
6) some useful plant and animal products e.g. wood and fossil fuels, are burned (combustion). This also released co2 back into air
7) decomposition of materials means that habitats can be maintained for the organisms that live there e.g. nutrients are returned to the soil and waste material such as dead leaves don’t just pile up
4 steps of water cycle
1) energy from sun makes water evaporate from land and sea turning it into water vapour, water also evaporates from plants-transpiration
2) the warm water vapour is carried upwards when it gets higher, it cool and condenses to form clouds
3) water falls from the clouds as precipitation onto land, where it provides fresh water for animals and plants
4) it then drains into the sea and the whole process restarts
Why is the water cycle important
If it wasn’t for the water cycle recycling water, we’d quickly run out of the stuff and no plants would be able to survive
What is desalination
Removes salts from salt water to produce potable water
What is thermal desalination (distillation)
Where salt water is boiled in a large enclosed vessel so that the water evaporates, the steam rises to the top of the vessel but the salts stay at the bottom, the steam then travels down a pipe from the top of the vessel and condenses back into pure water
Steps to reverse osmosis as a method of desalination
1) salt water is first treated to remove solids, before being fed at a very high pressure into a vessel containing a partially permeable membrane
2) the pressure causes the water molecules to move in the opposite direction to osmosis - from higher salt concentration to lower
3) as the water is forced thru the membrane, the salts are left behind, removing them from the water
How are nitrates made available for plant uptake
Nitrogen in the air has to be turned into mineral ions such as nitrates before plants can use it, plants absorb these mineral ions from the soil and use the nitrogen in them to make proteins, nitrogen is then passed along food chains in the form of proteins, as animals eat plants
What do decomposers do
Break down proteins in rotting plants and animals and urea in animal waste, this returns nitrogen to the soil - so the nitrogen in these organisms is recycled
How is nitrogen turned into nitrogen contains ions for plants
1) Lightning - there’s so much energy in a bolt of lightning that it’s enough to make nitrogen react with o2 in the air to give nitrates
2) nitrogen-fixing bacteria in roots and soil - turn atmospheric N2 into ammonia, which forms ammonium ions
What does nitrifying bacteria do
Turns ammonia in decaying matter into nitrites and then into nitrates
What does nitrogen-fixing bacteria do
nitrogen-fixing bacteria in roots and soil - turn atmospheric N2 into ammonia, which forms ammonium ions
What does denitrifying bacteria do
Turns nitrates back into nitrogen gas, often found in waterlogged soils.
Where do nitrogen fixing bacteria live
In the soil, in nodules on the roots of legume plants (peas and beans)
What two ways can farmers increase the amount of nitrates in the soil to help their crops grow better and how
1) crop rotation- instead of growing the same crop in a field year after year, different crops are grown each year in a cycle. The cycle usually includes a nitrogen-fixing crop (peas/beans) which helps put nitrates back into soil for other crops following years
2) fertilisers- spreading animal manure or compost on fields recycles the nutrients left in plant and animal waste and returns them to the soil through decomposition, artificial fertilisers containing nitrates can also be used but can be expensive
