topic 9 - ecosystems and material cycles

Question 1

What is an individual

Answer 1

A single organism

Question 2

What is a population

Answer 2

All the organisms of one species in a habitat

Question 3

What is a community

Answer 3

All the organisms of different species living in a habitat

Question 4

What is a ecosystem

Answer 4

A community of organisms along with all the non-living conditions

Question 5

What are abiotic factors affecting communities

Answer 5

Temperature
Light
Water
Pollutants

Question 6

What are biotic factors

Answer 6

Competition
Predation

Question 7

Importance of interdependence in a community

Answer 7

A change in the population of one species can have huge knock on effects for other species in the same community

Question 8

How does mutualism help organisms survive

Answer 8

• it’s a relationship between two organisms, form which both organisms benefit

Question 9

How does parasitism help organisms survive

Answer 9

• parasites lives very closely with a host species
• the parasite takes what it needs to survive, but the host doesn’t benefit

Question 10

CORE PRACTICALS

Answer 10

Mark out a line in the area you want to study
Then collected data along the line using quadrat place next to each other. If your transit is quite long, you could place the quadrats at regular intervals instead. Collect data by counting all the organisms of the species you’re interested in, or by estimating percentage cover. This means estimating the percentage area of a quadrat covered by particular type of organism.
You could also record other data, such as main height of the plant you’re counting all the abiotic factors in each quadrat
Repeat steps one and two several times then find the main number of organisms or main percentage cover
Plot graphs to see if the changing abiotic factor is correlated with the changing distribution of the species you’re studying

Question 11

A 1200 m² field was randomly sampled for Buttercup using a quadrat with an area of 0.25 m². A mean of 0.75 buttercup were found per quadrat. estimate the total population of Buttercup.

Answer 11

0.5 X4 = three buttercup per metre squared
3X 1200 = 3600 Buttercup in total

Question 12

How can fish farming reduce biodiversity

Answer 12

• food is added to the next to feed the fish, which produce huge amounts of waste. Both the food and the waste can leak into open water, causing eutrophication and the death of wild species.
• fish comes in open water often acts a breeding ground for large numbers of parasites. These parasites can get out of the farm and infect wild animals, sometimes killing them.
• Predators are attracted to the nets and come become trapped in them and die
• sometimes farmed fish can escape into the wild, which can cause problem for wild populations of indigenous species

Question 13

How can non-indigenous species reduce biodiversity

Answer 13

• A non-indigenous species is one that doesn’t naturally occur in an area. They can be introduced intentionally or unintentionally. The introduction of a non-indigenous species mate cause problems for indigenous species.
• non-indigenous species compete with indigenous species for resources like food and shelter. Sometimes, they are better at getting these resources and out compete the indigenous species which decrease in number and eventually die out.
• non-indigenous species sometimes also bring new diseases to a habitat. These often infect and kill lots of indigenous species reducing the habitats biodiversity .

Question 14

How can eutrophication reduce biodiversity

Answer 14

Eutrophication is an excess of nutrients and water which can lead to death of many species present in the water

Question 15

How can we increase biodiversity in reforestation?

Answer 15

Refer station is when a land where a forest previously stood is replanted to form a new forest
Forest generally have a high biodiversity because they contain a wide variety of treason plants and these provide freedom water for lots of different animal species. Deforestation reduces the biodiversity by removing the trees.
Reforestation programs need to be carefully planned to maximise positive effects and minimise -ones

Question 16

How does conservation schemes protect biodiversity?

Answer 16

Protecting a species natural habitat
Protect protecting species in safe areas outside of their natural habitat and introducing captive breeding programs to increase numbers
the use of seed banks to store and distribute the seeds of rare and endangered plants

Question 17

What benefits of maintaining biodiversity on a local and global scale?

Answer 17

Protect protecting the human food supply
Ensuring minimal damage to food chains
Providing future medicines
Culture aspects
Ecotourism
Providing new jobs

Question 18

How do different material cycle through the abiotic and biotic components of a ecosystem?

Answer 18

Living things are made of elements they take from the environment
They turned his element into the complex compounds that make up living organisms. Elements are passed along food chains when animals eat the plants and each other.
The elements are recycled – waste products and dead organisms are broken down by decomposers 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

Question 19

How does the carbon cycle work?

Answer 19

Green plants use the carbon from carbon dioxide to make carbohydrates, fats and proteins.
Eating passes the carbon compounds in the plant along two animals in a food chain.
Both plant and animal respiration while the organisms are alive releases carbon dioxide back into the air.
Plant animals eventually die in decompose, or are killed and turned into useful products.
When planting animals decompose their broken down by microorganisms, such as bacteria and fungi. These decomposers release carbon dioxide back into the air by respiration, as they break down the material.
Some useful planting animal products, are burnt. This also releases carbon dioxide back into the air.
Decomposition of materials means that the habitats can be maintained for the organisms that live there, such as dead leaves, doesn’t just pile up

Question 20

Describe the role of microorganisms in the carbon cycle

Answer 20

Microorganisms in the carbon cycle are decomposers. They breakdown dead organisms and waste products and release carbon dioxide through respiration as they do so.

Question 21

What is the water cycle?

Answer 21

Energy from the Sun makes water evaporate from the land and sea, turning it into water vapour. Water also evaporates from plants – this is known as transpiration.
The warm water vapour is carried upwards. When it gets higher up, it causes and condenses to form clouds.
water falls from the clouds as precipitation on land, we provide provides freshwater for plants and animals.
it then drains into the sea and the whole process starts again.

Question 22

How can desalination be used to produce potable water from saltwater?

Answer 22

It remove salts from salt water. There are a few different methods of desalination. One really simple method is thermal desalination. This is where water is boiled in a large enclosed vessel so that the water evaporates. The steam rises to the top of the vessel, but the salt stay at the bottom. The sea then travels down the pipe from the top of the vessel and condensed back into pure water.

Question 23

Reversed osmosis is a modern method of what?

Answer 23

Desalination

Question 24

How come we use reverse osmosis as a modern method of desalination?

Answer 24

Salt water is first treated to remove solid, before being fed at a very high-pressure into a vessel containing a partially permeable membrane
The pressure causes the water molecules to move in the opposite direction to osmosis – from a higher salt concentration to a low salt concentration. As the water is forced through the membrane, the salts are left behind removing them from the water.

Question 25

Explain how water from the sea can eventually fall as rain

Answer 25

Energy from the Sun makes water from the sea evaporate, turning into water vapour. The water vapour is carried upwards, as warm air rises. When it gets higher up, it causes and condenses to form clouds. Water falls from the clouds as precipitation, usually as rain.

Question 26

Describe how the nitrogen compounds in dead leaves are turned into nitrates in the soil

Answer 26

Decomposes breakdown dead leaves and release ammonia. The nitrifying the bacteria turn the ammonia into nitrates and then into nitrates

Question 27

How does the nitrogen cycle work?

Answer 27

The atmosphere contains 78% nitrogen gas. This is very unreactive and so it can’t be used directly by plant or animals. Nitrogen is needed for making proteins for growth, so living organisms have to get it somehow.
Nitrogen in the air has to be turned into mineral iron such as nitrates before plants can use it. Plants absorb these mineral irons 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. Decomposers break down the proteins and rotting plants and animals, and urea in animal waste. This returns nitrogen for the soil – so the nitrogen in these organisms is recycled.
Nitrogen fixation is the process of turning nitrogen from the air into nitrogen containing ions in the soil which plants can use. There are too many ways that this happens:
- Lightning – there’s so much energy in a bolt of lightning that is enough to make nitrogen react with oxygen in the air to give nitrates
- Nitrogen fixing bacteria in roots and soil

Question 28

What are the four different type types of bacteria involved in the nitrogen cycle?

Answer 28

Decomposers – decompose proteins and urea and turn them into ammonia. Ammonia forms ammonium irons in solution that plants can use.
Nitrifying bacteria - turn ammonia into decaying matter into nitrates than into nitrates
Nitrogen fixing bacteria – turn atmospheric nitrogen into ammonia, which forms ammonium irons
Denitrifying bacteria – turns nitrates back into nitrogen gas. This is of no benefits of living organisms. Denitrifying bacteria are often found in waterlogged soils.

Question 29

How can crop rotation increase the amount of nitrates in the soil?

Answer 29

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, which helps to put nitrates back into the soil for another crop to use the following year.

Question 30

How do fertilisers increase the amount of nitrates in the soil?

Answer 30

Spreading animal manure or compost on fields recycle the nutrients left and plant and animal waste and returns them to the soil through decomposition. Artificial fertilisers containing nitrates can also be used, but these can be expensive.