Topic 9: Ecosystems Flashcards
1
Q
What do organisms need to stay alive?
A
They need resources. Plants need space to get light, water, carbon-dioxide, oxygen, warmth and mineral ions.
Animals need oxygen, food and water. They also need somewhere to shelter from the weather or avoid predation from other animals. This means that organisms are continually interacting with each other and their environments.
2
Q
What is an ecosystem?
A
An area in which all the living organisms and all the non-living physical factors from a stable relationship that needs no input from outside the area to remain stable.
3
Q
What is a community?
A
All the organisms that live and interact in an ecosystem form a community.
4
Q
What is a population?
A
A group of one species living in the same area.
5
Q
What does interdependent mean in terms of species?
A
When species are dependant on each other for resources that are dependant on each other for resources.
6
Q
What is a habitat?
A
Where populations live within an ecosystem. A habitat includes the other organisms that affect the populations and local environment.
7
Q
Define the term abundance:
A
A measure of how common something is an area, such as its population size.
8
Q
What is a quadrat?
A
A square frame of known area, such as 1m sq, that is placed on the ground to get a sample of the organisms living in a small area.
9
Q
Why do we use quadrats?
A
Because it is impossible to measure population size by counting all the organisms in an area. Quadrats give an estimate.
10
Q
How do we use quadrats?
A
They are placed randomly in an area, and the number of individuals in each quadrat is counted.
11
Q
What is the equation to estimate population size?
A
Population size = number of organisms in all quadrats x total size of area where organism live/total area of quadrats
12
Q
What is a food web?
A
This shows the feeding relationships between the organisms in a community.
13
Q
Why do we use food webs?
A
We use them to help predict what will happen if there are changes in the ecosystem.
14
Q
What are the different categories of a food web?
A
Predators/tertiary consumers: Eat secondary consumers and sometimes primary consumers. They eat thing below them in the food chains and are carnivores/omnivores.
Primary consumers: the first trophic level of consumers. Primary consumers are herbivores. Herbivores eat plants but not other animals.
Secondary consumers: carnivores that eat primary consumers/herbivores.
15
Q
What is the difference between abiotic and biotic factors?
A
Abiotic: Non-living conditions that can influence where plants or animals e.g temperature, light intensity.
Biotic: living components (the organisms) in an ecosystem.
16
Q
Where is sunlight energy transferred to and how does this affect abiotic and biotic factors?
A
A lot of the suns energy is transferred to substances in new plant biomass (the mass of tissue). The rest is transferred it the environment by heating, during processes such as respiration.
Other organisms cannot make use of this energy transferred to the environment from the sun by heating so these energy transfers are less useful.
17
Q
Define the term biomass:
A
The total mass in living organisms, usually shown as the mass after drying.
18
Q
What is biodiversity?
A
The variety of species in an area.
19
Q
What is meant by trophic levels?
A
Feeding levels in a food chain, such as, produces, primary consumer, secondary consumer, predator.
20
Q
What happens to the energy when a primary consumer (herbivore) eats a produces and when a secondary consumer eats a primary consumer?
A
The energy stores in the plants biomass is transferred to the herbivore when it eats it. The energy stored in the primary consumer is then transferred to the carnivore/secondary consumer that eats it.
21
Q
During a food web why might not all the energy transferred from e.g the plant to the herbivore be transferred to the carnivore that’s eats the herbivore?
A
- when the herbivore eats the producer some of the energy is transferred from the herbivore to the surroundings by heating during metabolic processes, e.g respiration.
- some energy is stores in the herbivores waste/urine, which is not able to the predator to eat.
- the predator may not be able to eat all of the herbivore e.g eyes (etc)
22
Q
What is a sankey diagram?
A
This shows energy transfers, where the width of each arrow is proportional to the amount of energy is represents.
23
Q
What equation can you use to work out the efficiency of an energy transfer?
A
Energy transferred to biomass/total energy supplied to organism
To get it as a % multiply by 100.
Usually the numbers are between 0-1. 1 being 100% efficient.
24
Q
What is a pyramid of biomass?
A
When all the biomass organisms is measured at each trophic level in an ecosystem, they can be displayed as a pyramid of biomass.
(Diagram showing the amount of biomass at different trophic levels in a food chain)
25
How can we interpret a pyramid of biomass?
The diagram usually has a pyramid shape because energy is transferred from the food chain to the environment at each Tropic level. With less energy available less biomass can be produced.
26
Why is the pyramid of biomass useful?
It helps explain why there is a limit in a food chain. Eventually the energy becomes too little to support animals higher up the food chain.
27
What is meant by the distribution of organisms?
Where organisms are found in an ecosystem.
28
How can the distribution of organisms be affected?
Physical and chemical factors, such as temperature, rainfall and substances in the soil.
29
How can the abiotic factors on the distribution of organisms in an ecosystem be measured?
Using a belt transect. Quadrats are places along a line in an habitat and the abundance of organisms are measured as well as the abiotic factors in each quadrat position. Changes in abundance can show which abiotic factors has the greatest affect on the organism.
30
Define the term adaptation:
The features of something that enable it to do a certain sanction or job.
31
How could droughts or flood cause species to die?
Few organisms can survive a drought for long. Most land plants cannot survive if their roots are under water for too long. Of the climate change results in more flooding or more drought, then many species in different communities may die out.
32
How can temperature affect the distribution of organisms?
All organism adaptations that make them suited to life at particular temperatures. A long-term rise or fall in temperature in an eco-system will change the distribution of some organisms and so affects the whole community.
33
Why do most algae live within 30m of the oceans surface?
They need light to photosynthesise in order to survive. Most algae can get enough light sighing 30m of the surface. However, on land light is limited in forests, which is why that only few plants grow on the forests floor due to the dense trees and forest above it.
34
What are pollutants?
Substances that cause harm in the environment.
35
What is the effect of pollution and what causes pollution?
Human activity causes pollution as they release pollutants. These can poison organisms or chase harm to organisms in other ways (such as plastics being eaten by fish and other organisms)
36
Why is energy lost in a food chain?
- Not all the organism is eaten.
- life processes of the organism that is being eaten requires energy (e.f for respiration). This energy is lost.
- energy used up by organism for processes like temperature regulation.
- the organism will have used energy through movement.
- some energy is lost through the excretion of waste materials.
37
Core practical: Quadrats and Transects
How can you study and measure the affects of abiotic factors(sunlight intensity) on an abundance of plants using a belt transect?
1) peg out a long tale measure (at least 20m) on the ground, starting were there is no shade and ending in heavy shade. This is the transects line.
2) make measurements along regular intervals along transect of how many daisies there are. (your intervals may depend on how long the transect line is and the time you have to record information.)
3) place the top left hand corner of the quadrant at a measurement point on the transect line.
4) measure the abiotic factors at that point and record them.
5) Record the abundance of your selected plants in the quadrat.
6) Repeat steps C-E at each measurement point along transect.
38
What are the dependant and independent variables for the Quadrat and Transect practical?
Independent- amount of sunlight.
| Dependant- how many daisies in each quadrat.
39
What are 2 abiotic factors linked to climate?
- temperature
| - rainfall
40
What does predation mean?
When one animal species kills and eats another animal species.
41
What is meant by completion between organisms?
When organisms need the same resources as each other to survive, they struggle against each other to get those resources. We say that they ‘compete’ for those things.
42
What is the predator-prey cycle?
The regular variation in numbers of predators and numbers of prey within a feeding relationship.
43
What is an indicator species?
Organisms that are sensitive to polluting chemicals e.g lichen. They can indicate how much pollution there is in an area by how many of these organisms can be found.
44
What are lichen?
Lichen grow on trees. Lichens have a mutualistic relationship between a fungus and an alga. They cannot grow well in places with high pollution (e.g near factories or cities) so are only found in places with low pollution.
45
What is another indicator species apart form lichen?
Black spot fungus is pathogen of roses. The fungus cannot grow well of there’s a lot of soulful pollution. So therefore roses growing in cities rarely suffer from the black spot infection.
46
How is water pollution caused?
Fertilisers, sewage, substance released by factories such as mercury or detergents are all sources of water pollution along with many more.
47
What is eutrophication?
The addition of more nutrients to an ecosystem than it normally has. (E.g nitrates from fertilisers). This causes rapid growth of algae and plants.
48
What affect does eutrophication have on the local environment?
Eutrophication encourages the rapid growth of algae and fungi. The bacteria that feed on the dead plants and algae then reduce the oxygen concentration on the water because they use a lot of it. This kills many aquatic animals like fish that live in the water. The bacteria and then feed of all the dead organisms rub out food and die off and allowing more aquatic organisms to reproduce again. The process keeps repeating.
49
How well are some aquatic species of invertebrates adapted to living in water pollution?
Stone fly nymph Low level of pollution/if any at all
Dragon fly nymph
Fresh water shrimp
Water louse
Blood worm
Sludge worm
(No life) Extreme levels of pollution
50
What is the trend in the complexity of water invertebrates as the water pollution increases?
The more polluted an area the more simplistic(smaller and less complex) the organism is as there are more polluting gases limiting its growth). The less polluted an area is the more complex and organism is and the more complex is system is. This is because they have a lot of oxygen to develop and adapt where as in highly polluted areas they have very little oxygen to grow.
51
How can both water and air pollution be measured?
Using sensors. These give numerical data values at the time of measurement.
Pollution indicator species do not give a numerical value or this level of detail in a measurement, but they are useful as a simple assessment of the long term health of an ecosystem.
52
What is parasitism?
This is a different kind of feeding relationship, in which one organism (a parasite) benefits by feeding on its host organism, causing harm to the host. The parasite lives in or on the host. The host many continue to survive for a long time and continue to provide food for the parasite if the parasite causes limited harm.
53
How are the parasites tape worms adapted to live inside their host?
- hooks and suckers attach to the worms head firmly to the hosts intestine wall.
- segments of its body contain male and female sex organs so fertilisation can occur.
- a flattened body allow absorption of nutrients over whole surface without need for digestive or circulatory systems.
54
How are the parasites head lice adapted to live on their host?
- sharp mouthparts to pierce skin and suck blood.
- sharp claws grip onto hair and skin.
- eggs are glued to hair to stop them falling off so they can reproduce successfully.
55
What is meant by a mutualistic relationship?
A relationship between individuals of different species where both individuals benefit.
56
Give an example of a mutualistic relationship?
Flowers depend on insects for pollination. The flower benefits by being able to produce fertilised egg cells, and the insect benefits by being collecting nectar pollen from the flower, which it uses for food.
57
Define the term indigenous/native species:
Organisms that have always been in a specific area, region of country.
58
What is a non-indigenous organism?
Organisms that have been introduced into the area and where not always found there.
59
What is fish farming?
Growing fish in pens for food.
60
What is meant by overfishing?
Taking more fish from a population than are replaced by the fish reproducing so that the population falls over time.
61
What is the aim of fish farming?
Fish farming aims to produce more fish and so reduces the overfishing of wild fish.
FISH FARMING MAINTAINS BIODIVERSITY AS IT CUASES LESS DAMAGE TO THE FOOD WEB THAN CATCHING WILD FISH.
62
What are the problems of fish farming?
Fish farming causes problems because so many fish are kept in a relatively small space. Uneaten food and faeces from the fish sink to the bottom if the water. This can change conditions, which many harm the wild organisms that live there. Parasites and disease can spread more easily between fish in pens so the fish need to be treated to keep them healthy.
63
Why are some non indigenous species introduces to an area?
In order of affect the ecosystem, such as reduce the numbers of another species that has got out of control. This often happens after humans have changed the ecosystem and affected the food web.
64
What is a problem with introducing a non-indigenous species to an area?
The species may grow out of control because it may not have the limitations it did in its old habitat. E.g it may over populate in its new hotter climate because the cold winters don’t kill some of its population anymore. Or it’s main predator may not be in this new region to kill it so it overpopulated and causes damage to the ecosystem and food web. May eat too much of another species that causes it to become extinct.
65
What is the cycle for eutrophication involving fertiliser?
1) fertiliser is added to a field.
2) heavy rain washes fertiliser off.
3) nitrates and phosphates dissolve in soil water.
4) nitrates and phosphates not taken up by plants are washed into stream or river.
5) high nitrate and phosphate concentrations in the water encourage plants and algae to grow rapidly.
66
What does reforestation mean?
Planting new forest where old forest has been cut down.
67
What are some of the benefits of reforestation?
It increases the range of habitats and increases the number of species living in a certain area.
68
What is a conservation?
When an effort is made to protect a rare or endangered species or habitat by setting up a conservation or reserve where it can live safely in order to help increase its numbers.
69
What is an endangered species?
A species that is at great risk of destruction.
70
How can the conservation of a species be made easier?
If the habitat is also protected. However, the Haitians of many rare species are being damaged or destroyed.
71
Why are some species endangered?
- Its habitat is begun destroyed.
- its food sources are being killed.
- its being hunted for a specific reason (e.g its fur or other body parts).
- to prevent that animal for harming live stock or villages in rural areas.
72
Define the term captivity?
Keeping something in unnatural surroundings, such as animals in a zoo.
73
How are tigers being protected?
Being held captive in zoos to increase their numbers but their habitats need to be rebuilt and protected to so they can reproduce and survive on their own. These habitats also need to be linked to others can roam more widely and find mates. Tigers originally live in dense forest which is being cut down for wood and urbanisation.
74
Why is protecting biodiversity important?
- for conserving individual species or communities.
- areas with greater biodiversity can recover faster from natural disasters such as flooding.
- we use plants and animals as source’s for food, medicine and products.
- as conditions change we may need a new variety of plants and animals to provide what we need. So it is important we try and preserve as many species as we can.
75
What does food security mean?
Having access to enough save and healthy food at all times.
76
How has food security been increased?
Through improving agricultural methods, such as using fertilisers and more productive varieties and breeds.
77
What challenges may food face?
- it is difficult in poor counties or where there is conflict.
- may become more difficult due to the rising population of humans.
78
What is an agriculture inputer?
Something needed for growing food such as farm equipment, fertilisers and pesticides for crops.
79
How does growing food from crops cause problems with agricultural inputs like fertilisers?
Fertilisers increase plant growth and yield of crops. The amount of fertiliser used in the last 50 years has increased significantly. Most this fertiliser is being made using chemicals processes that need energy and release carbon dioxide. This raises concerns about sustainability mad the harm on the environment.
80
What causes climate change?
Increasing carbon emissions from humans activities are leading to climate change.
81
How does climate change effect pests and pathogens?
This can lead to pests and pathogens moving into a new area. E.g midges, which are vectors for for the virus that causes blue tongue disease, are killed by cold temperatures.
82
What is a vector?
Something that transfers things from one place to another.E.g an organism that carries a pathogen from one infected person to another.
83
How doe biofuels work and how do they reduce carbon emissions?
One idea to reduce carbon emissions is to grow plants for biofuels to replace fossils fuels. The carbon released by burning a biofuel is only the amount removed from the air by the crop as it grew.
84
Why must substances such as carbon, nitrogen and water be recycles through organism and the environment?
In order to support life. There are only limited amounts of these substances on Earth so must be recycles as all organism need different substances from the environment to stay alive.
85
What is the water cycle?
A sequence of processes by which water moves through the abiotic and biotic parts of an ecosystem.
86
What are the different stage pens of the water cycle?
1) water evaporates from the oceans/lakes/rivers to form water vapour.
2) as air rises it cools and the water vapour in it condenses to form clouds.
3) as water droplets get too large and heavy they fall as rain or snow depending on how cold it is.
4) they droplets fall into lakes and rivers or the surface run off ends up in rivers.
5) the river then flows to the sea and the prices happens again.
87
What is ground water?
Water that moves through soil and rocks.
88
Why is water a vital part of our body?
Because it Male sup about 60% of our body. Much of the cells cytoplasm in our bodies are water, and reactions of substances often take place there. We are continually losing water to the environment so we need to take in more water to replace it. As a result humans can only sit be a few days without water.
89
What is desalination?
Obtaining fresh water from the sea or salty water. Several methods are used to do this including distillation.
90
What is distillation?
Where water is evaporated, c denied and collected. Used in desalination because when the water evaporates it leaves behind the salt as it has a much higher boiling point than water.
91
Do plants contain nitrogen?
Yes they contain nitrogen compounds in proteins and DNA.
92
Why do plants need nitrogen?
To grow well plants need nitrogen to make more of these nitrogen compounds found in proteins. They cannot use inert nitrogen in the air. Instead they absorb nitrogen compounds such as nitrates that are dissolved in soil water.
93
How is soil fertility maintained?
By decomposers such as bacteria in the soil. These organisms release nitrogen compounds together with carbon compounds when they decompose dead plants, animals and their waste.
Farmers take advantage of this when they add manure to their fields.
94
Why do farmers add fertilisers onto their fields and crops?
They spread artificial fertiliser to also increase soil fertility as they contain nitrogen compounds in fertilisers that are soluble and dissolve in water. This helps plants grow well and increases their yield.
95
What are nitrogen fixing bacteria?
Soil bacteria that can convert nitrogen gas into complex nitrogen compounds in the soil.
96
Where can nitrogen-fixing bacteria be found?
The bacteria are protected/found inside nodules in plant roots. The plant gets nitrogen compounds directly form grr bacteria.
Some plants such as peas work like this so they have a mutualistic relationship with the nitrogen-fixing bacteria.
97
How can farmers take advantage of nitrogen fixing bacteria?
Plants can make use of the mutualistic relationship between the bacteria and some plants to keep their soil fertile, by planting the crop (e.g peas) and then digging in the roots into the soil again after the crop has been harvested. The following year a different crop will benefiting from the additional nitrogen compounds.
98
What is crop rotation and why is it important in the nitrogen cycle?
When a different crop is planted in the same field each year in a 3-4 year cycle. This helps to control the build up of soil pests for each crop.
99
What is the nitrogen cycle?
A sequence of processes by which nitrogen moves from the atmosphere through living and dad organisms, into the soil and back into the atmosphere.
100
What are decomposers and what do they do?
Decomposers are organisms that feed on dead material, causing it to decay. They break down the soft tissues of an organism soon after the organism dies.
101
Define the term decay:
A process in which complex substances in dead plants and animal biomass are broken down by decomposers into simpler substances.
102
What conditions are best for decomposers?
These mircoorganisms grow best in warm and moist conditions, many of them need oxygen.
103
Decay can cause problems, particularly with keeping food fresh. Most methods of preservation rely on:
- reducing temperatures (e.g fridges and freezers).
- reducing water content, e.g by salting and then drying meat to make ham or salami.
- irradiation of packages food to kill decomposers.
- reducing oxygen, e.g storing foods in oil. Food that easily decay (e.g salad leaves) are often packages in inert gas like nitrogen.
104
What is the positive effect/outcome of decomposers on dead plant material?
The effect of decomposers on dead plant material can be useful. Many gardeners collect waste garden material into a heap, and keep it until it is well-decayed, forming compost.
105
What is compost and what does it contain?
The compost contains many of the nutrients that were in the plant tissue. However the decay process leaves them in a form that makes it easier for plants to absorb. Spreading compost on a garden increases fertility.
106
How can the rate of decomposition be measured?
Rate of decomposition = change of quantity (e.g mass)/time
107
What is the positive effect/outcome of decomposers on dead plant material?
The effect of decomposers on dead plant material can be useful. Many gardeners collect waste garden material into a heap, and keep it until it is well-decayed, forming compost.
108
What is compost and what does it contain?
The compost contains many of the nutrients that were in the plant tissue. However the decay process leaves them in a form that makes it easier for plants to absorb. Spreading compost on a garden increases fertility.
109
How can the rate of decomposition be measured?
Rate of decomposition = change of quantity (e.g mass)/time
110
What is the carbon cycle?
A sequence of processes by which carbon moves from the atmosphere, through living and dead organisms, into the atmosphere again.
111
What does carbon get used for in a plant after it photosynthesises?
CO2 molecules in the atmosphere diffuse into plant leaves. Inside a leaf photosynthesis may cause the carbon atom in the molecule to become part of another molecule, glucose.
