Topic 9: Ecosystems and Material Cycles

Question 1

define an individual

Answer 1

single organism

Question 2

define population

Answer 2

all the organisms of one species in a habitat

Question 3

define a community

Answer 3

all the organisms of different species living in a habitat

Question 4

ecosystem

Answer 4

a communit of organisms along with all the abiotic conditions

Question 5

define interdependence

Answer 5

when organisms depend on each other for things like food and shelter in order to survive and reproduce

Question 6

define mutualism

Answer 6

is a relationship between to organisms, from which both organisms benefit

Question 7

what do parasites do

Answer 7

parasite takes what it needs to survive from the host but the host doesn’t benefit

Question 8

name some abiotic factors that affect communities

Answer 8

• temperature
• amount of water
• light intesnity
• levels of pollutants

Question 9

Give an example of how temperature affect communities

Answer 9

• the distribution of bird species in Germany is probably changing because of a rising average temperature. For instance European bebird is a Mediterranean species, but it’s not present in Germany.

Question 10

Describe how the amount of water can affect communities

Answer 10

If the soil becomes waterlogged, or too dry, the population of plants will decrease

Question 11

Describe how light intensity affects communities using an example

Answer 11

As trees grow and provide more shade, grasses may be replaced by fungi, which are better able to cope with the low light intensity

Question 12

Describe using an example, how levels of pollutants affect communities

Answer 12

Lichen are unable to survive if the concentration of self dioxide is too high

Question 13

Describe how the biotic factor competition affects communities

Answer 13

Organisms, compete with other species for the same resources, E.G.red and grace girls live in the same habitat and eat the same food. Competition with the grace girls for these resources. Some areas means there’s not enough food for the red squirrels to the population of red squirrels is decreas.

Question 14

Describe the biotic factor predation affects communities using an example

Answer 14

The number of lions decreases the number of gazelles might increase because fear of them will be eaten by lions

Question 15

Describe the importance of interdependence in a community

Answer 15

Any changes within the population can cause huge knock-on effects on the rest of the community.

Question 16

Describe how to use a quadrat to study the distribution of small organisms

Answer 16

• place a 1 m² quadrant on the ground at a random point within the first sample area. You could do this by dividing the sample area into a grid and using a random random number generator to pick coordinates to place your quadrat at. This will help to make sure the results you get are representative of the whole sample area.
• Count all the organisms you’re interested in within the quadrat
• repeat step, one and two many times
• work out the main number of organisms per quadrat within the first sample area by using the formula

mean = total number of organisms/number of quadrat

• repeat steps 1-4 in the second sample area
• finally compared to me. E.g. you might find the meaning of two daisies per metre squared in one area and 22 daisies permit, squared in the other area.

Question 17

What is a quadrat?

Answer 17

A square frame, enclosing a known area e.g. 1 m²

Question 18

How do you estimate population size of a small area?

Answer 18

• work out the main number of organisms per m2
• multiply the main metre^2by the total area of a habitat

Question 19

Describe how to use belt transact to study distribution along a gradient

Answer 19

• mark out a line in the area you want to study, e.g. from the hedge to the middle of a field
• then collect data along the line using quadrat place next to each other. If your transact is quite long, you could place the quadrat at regular tools, for example, every 2 m instead. Collect data by counting all the organisms of the species interested in, or by estimating percentage cover. This means estimating the percentage area of a quadrat covered by a particular type of organism.
• you could also record other data such as the main heights of the plant counting or the abiotic factors in each quadrat could use a light meter to measure light intensity
• step one and two several times, and then find the main number of organisms or mean percentage cover for each quadrat
• plot graphs to see if the changing abiotic factor is correlated with the change into the distribution of the species, you are studying

Question 20

What is a source of energy for nearly all life on earth?

Answer 20

The Sun

Question 21

What happens to the energy that plants use in the food chain?

Answer 21

Plants, convert a small percentage of light energy that falls onto them into glucose. They use some of the glucose immediately and respiration and store some of the rest as biomass.

Question 22

Explain how energy passes along the food chain

Answer 22

• plants, convert a small percentage of the light energy that falls on them into glucose. The use of the glucose immediately and respiration and some of the rest is stored as bass.
• the rabbits in the trophic level, then eats the plant. It uses some of the energy it gets from the plant, and some of the rest is stored in the body is biomass. Then the fox in the next trophic level, eat the rabbit and get some of the energy stored in the rabbits biomass. This is a simple food chain.

Question 23

Describe and explain what energy is passed along the food chain and what isn’t

Answer 23

• energy is used by organisms that each stage of the food chain stay alive, for example for processes like respiration, which transfers energy for all life, processes, including movement. But a lot of energy is transferred to the surroundings by heat.
• this energy isn’t stored as bias so it isn’t transferred to the organisms in the next trophic level. It’s the food chain
• Energy that does not get stored by mask. Doesn’t all get transferred for the next trophic level either. This is because not all of an organism eaten, e.g. the bones because not all the bits that do not eat can be digested, undigested material is lost from the food chain in faeces

Question 24

What do pyramids of biomass show?

Answer 24

Shows how much the creatures at each level of a few chain Woodway if you put them together

• since biomass is a store of energy, a pyramid of biomass also shows how much energy there is it each stage of the food chain

Question 25

What is the trend shown of a pyramid of biomass?

Answer 25

Each time you go one trophic level, the mass of organisms goes down. This is because most of the biomass/energy is lost and so does not become biomass in the next level up. This gives the pyramidal shape.

Question 26

How to draw a pyramid of biomass

Answer 26

In the exam, they will give you all the information you need
- the first level is always the produce
- the second level is always the primary consumer
- the second level is the secondary consumer and so on
- draw each bar to a sensible scale

Question 27

What do the numbers show in this picture?

Answer 27

The amount of energy transferred to the next level
E.g. the rosebush transfers, 80,000 kJ of energy to the green flies and so on

Question 28

How can you calculate the energy loss between different trophic levels?

Answer 28

Energy loss= energy available at previous level - energy transferred to the next level

e.g. 80,000 take away 10,000 equals 70,000 kJ lost.

Question 29

How can you calculate the efficiency of the energy transfer between level?

Answer 29

Question 30

How do you calculate the biomass loss between trophic levels or the efficiency of biomass transfer?

Answer 30

Use the same formulas as the energy transfers and energy efficiency

Question 31

Define biodiversity

Answer 31

The variety of living organisms in an ecosystem

Question 32

And what situation would human activities have a positive effect on biodiversity?

Answer 32

Carrying out, conservation schemes or rainforest

Question 33

Describe how fertilisers can have a negative effect on biodiversity

Answer 33

Too much fertiliser is applied, and it rains afterwards. Nitrates easily find their way into rivers and lakes.
- This causes eutrophication which is an excess of nutrients in the water, and this can lead to the death of many species presents which reduces the diversity of the habitat

Question 34

Explain how fertilisers can reach into water and eutrophication

Answer 34

1. Fertilisers into the water, adding excess nitrates (more than plants in the water can
2. The excess nitrates cause algae to grow fast and block out the light.
3. Plants can’t photosynthesise due to the lack of light and starts to die and decompose.
4. With more food available, micro organisms that feed decomposing plants, increasing number and use oxygen in the water.
5. Organisms need oxygen for aerobic respiration like fish die.

Question 35

Explain how fish farms can reduce biodiversity

Answer 35

• food is added to the next to feed the fish, which produces huge amounts of waste. Both of food and the waves can leak into the open water, causing eutrophication and the death of wild species.
• Fish farms and open water often act as a breeding ground for large numbers of parasites. These parasites can get out of the farm and infect wild animals, sometimes killing them.
• predators, e.g. sea lions are attracted to the net and can become trapped in them and die
• sometimes fish can escape into the wild, which can cause, cause problems for whilst populations of indigenous species
• sometimes fish are found in large tanks rather than open botnets. These farms are loaned by diversity, because of often only one species is formed, but tanks often catch, free plants, and predators, and any parasites and microorganisms are usually killed.

Question 36

Explain how the introduction of a non-indigenous species can reduce biodiversity

Answer 36

• non-indigenous species is one that doesn’t naturally occur in the area. They can be introduced intentionally (E.G.for food or hunting) or unintentionally (E.E.as a stowaway in international cargo). The introduction of an non-indigenous species may cause problems for indigenous species.
• non-indigenous species, compete with indigenous species or resources like food and shelter. Sometimes they are better at getting these resources and outcompete the indigenous species, which decrease in the number and eventually die out
• for example, signal crayfish were introduced to the UK for food, but they pray on an outcompete, many indigenous, rivers, species reducing biodiversity
• non-indigenous species also bring new diseases to a habitat. These often infects and kill lots of indigenous species, reducing the habitats by diversity.

Question 37

Explain how reforestation can increase biodiversity and deforested areas

Answer 37

• reforestation is when land forest previously stood, is replanted for a new forest
• Forest generally have a high biodiversity because they contain a wide variety of trees and plants, and these provide food and shelter for lots of different animals species. Deforestation reduces the biodiversity by removing the trees (either by chopping them down or burning them). Reforestation helps to restore it.
• reforestation programs need to be carefully planned to maximise positive effects and minimise -ones. For example, planting a forest with a variety of species, will result in a higher diversity than replanting, using only a single type of tree.

Question 38

What are some conservation schemes that can help protect by diversity?

Answer 38

• protecting a species is natural habitat (so the individuals have a place to live)
• protecting species and safe areas outside of their natural habitat (E.animals could be protected in) and introducing captive, breeding programs to increase numbers
• the use of seed banks to store and distribute seeds of rare and endangered plants

Question 39

Describe how maintaining biodiversity has many benefits

Answer 39

• protecting the human food supply- over fishing has greatly reduced fish stocks in the world oceans. Conservation programs can ensure that future future generations will have fish to eat.
• ensuring minimal damage to food chains – if once species becomes extinct, it will affect all the organisms that feed on and are eaten by that species so the whole food chain is affected. This means conserving one species may help others survive.
• providing medicines – of the medicines we used to come from plants. Underscored plants species may contain new medicinal chemicals. If these plants are allowed to become extinct, you.G. through rainforest destruction, we could miss out on volleyball medicines.
• cultural aspects – individual species may be important to nations or areas. Cultural heritage, E.G.the bald eagle is being concerned by the USA, as it is regarded a national symbol.
• eco-Tourism – people are to visit beautiful, spoilt landscapes with a variety of animal and plants species. Eco-tourism (environmentally friendly tourism) help bring money into biodiverse areas where conservation work is taking place
• providing new jobs – things such as eco-tourism, conservation schemes, and reforestation schemes, provide employment opportunities for local people

Question 40

Define food security

Answer 40

Everyone has access to enough food that is safe for them to eat and have the right balance of nutrition

Question 41

What are some biological factors that affect the level of security?

Answer 41

Increasing human population
Increasing consumption of meat and fish, and increasing animal farming
Environmental changes caused by human activity
Sustainsability
New pets and pathogens

Question 42

Explain how increasing consumption of meat and fish and increasing animal farming is a biological factor that affects the level of food security

Answer 42

• as people become wealthier, their diets are likely to change to include a wide variety of foods, including more meat and fish (which are expensive to buy).
• there is less energy and less by us. Every time you move up the stage in a few chain, so forgiven area of land, you can produce a lot more food for humans by growing crops rather than by having grazing animals. Plus, animals and fish being rid to be eaten or often fed crops that would otherwise be eaten by humans, like corn.
• risk of fishing, wild fish, so that there won’t be enough available to catch in the future

Question 43

Explain how environmental changes caused by human activity affect the level of food security

Answer 43

• Burning fossil fuels releases lots of carbon dioxide, which is a greenhouse gas. Greenhouse gases naturally trapped energy in the atmosphere which helps keep the Earth warm but increasing levels of greenhouse gases are causing the global temperature to rise.
• Global warming as a type of climate change, and it causes other forms of climate change like changing rainfall patterns. Climate change may affect the growth of crops, which could reduce yields.
• of the changes caused by humans, such as soil pollution could also reduce your ability to grow crops

Question 44

Explain how sustainability affects the level of food security

Answer 44

• sustainability means the needs of today’s population without affecting the ability of the future generations to meet their needs. We must think about sustainability when addressing food security.
• for example, these are made from crude oil – nonrenewable fossil fuel that will eventually run out. There’s currently an increase in the growth of crops to make by yours.G.bio ethanol which is made by fencing, the sugar in corn and sugarcane. Buy fuels are renewable alternatives to fossil fuels – but they take up lamb that could be used for food crops. We need to balance our need for this to make with the need to gain more food now and in the future.
• also, the high input cost of farming (E.G.the price of fertilisers, fuel and machinery) may make it too expensive for farmers in some areas to continue farming and maintain food production in the future

Question 45

Explain, pests and pathogens affect the level of food security

Answer 45

• (E.g. some insects) and pathogens (e.g. bacteria/fungi) can cause damage to crops and livestock
• when some pathogens emerge, they can have a negative impact on yield. E.G.if a new disease spreads to crop, lots of the population may not be resistant to the disease. This means a large number of the crop plants will be damaged, reducing the yield and the amount that can be sold as food.

Question 46

How are materials recycled through both living and nonliving components of the ecosystems?

Answer 46

• living things are made from elements they take from the environment, e.g. plants taken carbon and oxygen from the air and nitrogen from the soil
• return these elements into 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 chain.

Question 47

Explain the carbon cycle that shows how carbon is recycled

Answer 47

• the carbon cycle is powered by photosynthesis. Green plants use the carbon carbon dioxide to make carbohydrates, fats and proteins.
• eating passes, the carbon compounds in the plant along to animals in the food chain
• based plants and animal respiration, while the organisms are alive, releases carbon dioxide back into the air
• plants and animals, eventually die, and decompose, or killed and turned into these products
• when plants and animals decomposed, broken down by microorganisms, such as bacteria and fungi. These decomposers release carbon dioxide back into the air by respiration, as the breakdown material.
• some useful plant and animal products, e.g. wood, and fossil fuels, are burned by combustion. This also releases carbon dioxide back into the air
• composition 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

Question 48

Describe the water cycle

Answer 48

• Energy from the Sun makes water evaporate from the land Sea, turning it into water vapour. Water also evaporates from the plants – this is known as transpiration.
• the warm water vapour is carried upwards. When it gets higher up, it causes and condensed form cloud
• waterfalls from the clouds as precipitation onto land, where it provides, freshwater for plants and animals
• then drains into the sea, and the whole process starts again

Question 49

What is a method for producing potable water?

Answer 49

Desalination

Question 50

Describe how desalination can be used to produce potable water from saltwater

Answer 50

• it removes salts from salt water
• thermal desalination is where saltwater is boiled in a large enclosed vessel, so that the water of evaporate. The steam rises up to the top of the vessel, but the salt stay at the bottom. The steam then travels down a pipe from the top of the vessel and condenses back into pure water.

Question 51

Describe how versus osmosis is a method of desalination

Answer 51

• saltwater is treated to remove solids, 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 high salt concentration to a lower salt concentration
• as the water is forced through the membrane, the salts are left behind, removing them from the water

Question 52

Explain the nitrogen cycle

Answer 52

• 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 and each other.
• decomposers like bacteria and fungi in the soil, breakdown, proteins in rotten plants, and animals, and in animal waste.

This returns to nitrogen to 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 use
- there are two main ways that this happens by lightning – there’s so much energy in a bottle of lightning that it’s enough to make nitrogen react with oxygen in the air nitrate. By nitrogen fixing bacteria in roots and soil.
- there are four different types of bacteria involved in the nitrogen cycle
a) decomposers – decomposed proteins in your ear and turn them into ammonia, ammonia forms, ammonium ions in solution that plants can use
b) nitrifying, bacteria – ammonia, indicating matter into nitrites, and then in nitrates
c) nitrogen, fixing bacteria – turn atmospheric nitrogen into Omonia, which forms ammonium ions
d) denitrifying bacteria – turn nitrates back into nitrogen gas. This is of no benefits of living organisms. Do notify bacteria are often found in waterlogged soils.
- some nitrogen fixing bacteria, live in the soil. Other live in nodules of the roots of lagoon plants. When these plants decompose, the nitrogen stored in them, and their nodules is returned to the soil. Nitrogen irons can also leak out of the nodules during plant growth. The plants have a mutualistic relationship with the bacteria – the bacteria get food from the plants, and the plants take gets nitrogen ions from the bacteria to make them into proteins.

Question 53

Describe ways in which farmers can increase the amount of nitrates in the soil

Answer 53

• crop rotation: this is where, instead of growing the same crop in a field year, after year, different crops are grown each year in a cycle. Cycle usually includes a nitrogen, fixing crops, EGP or beans, which helps put nitrates back into the soil for another property to use in the following year.
• fertilisers: spreading animal, manure or compost fields, recycles and nutrients, left in plants and animal waste and returns into the soil 3-D decomposition. Artificial fertilisers containing nitrates can also be used, but these can be expensive.

Question 55

How are indicator species used to show the level of water pollution?

Answer 55

• if your fertilisers containing nitrates are released into the river, then microorganisms in the water, increasing number and use up the oxygen
• some vertebrate animals, like Stonefall, lava and freshwater shrimps are good indicators for water pollution because they are very sensitive to the concentration of dissolved oxygen in the water. If you find stone fly lava in the river, it indicates that the water is clean.
• other vertebrate species have adapted to live in polluted conditions – so if if you see a lot of of them, you know there’s a problem, e.g. blood worms and sludge worms, indicates a very very high level of water pollution

Question 56

Explain how indicated species are used to show the level of air pollution

Answer 56

• pollution can be monitored by looking up particular types of lichen the are very sensitive to the concentration of sulphur dioxide in the atmosphere. The number and type of lichen at a particular location will indicate how clean the air is e.g. the air is clean if there are lots of lichen, especially bushy lichen , which need clean air and crusty lichen
• blackspot fungus is found on Rosie. It is also sensitive to level of sulphur dioxide in the air, so it’s presents will indicate clean air.

You might get data showing there are more lichen further away from the city centre. This is probably because outside the city centre, there is less pollution in the air contains less for dioxide and other pollutants.

Question 57

How can you use, indicate to species to mess with pollution?

Answer 57

• you could do a simple survey to see if a species is present or absent from an area. This is a quick way of telling whether an area is included or not, but is no good for telling how polluted an area is
• counting number of times and indicated species occurs in an area will give you a numerical value, allowing you to see roughly how polluted one area is in comparison with another

Question 58

What nonliving indicators can be used to measure pollution

Answer 58

• dissolves, oxygen, metres and chemical test are used to accurately measure the concentration of dissolved oxygen in water, to show how the level of water pollution is changing
• electronic meters, and various laboratory tests are also used to accurately measure the concentration of sulphur dioxide in air, to show how air pollution is changing.