Ecosystems Flashcards
1
Q
What do organisms need to stay alive?
A
Resources
2
Q
What do plants need to stay alive?
A
Light, water, carbon dioxide, oxygen, warmth and mineral ions.
3
Q
What do animals need to stay alive?
A
Oxygen, food, water, shelter
4
Q
What is an ecosystem?
A
An area in which all the living organisms and all the non-living physical factors form a stable relationship that needs no input from outside the area to remain stable./ All the organisms and the environment they live in.
5
Q
What do all the organisms that live and interact in an ecosystem form?
A
A community
6
Q
What is the community in an ecosystem made up of?
A
The community is made up of populations of different species. These species depend in each other for resources, so we say they are interdependent
7
Q
Each population lives in a particular habitat in an ecosystem. What does a habitat include?
A
A habitat includes the other organisms that affect the population and the local environment.
8
Q
What does interdependent mean?
A
When organisms in an area need each other for resources
9
Q
Why are organisms continually interacting with each other and their environments?
A
Because they rely on each other for resources.
10
Q
What is abundance?
A
Abundance is a measure of how common something is in an area, such as its population size.
11
Q
Measuring population size by counting all the organisms in an area is often impossible. How can you estimate the population size?
A
By taking a sample using a quadrats. Quadrats are placed randomly in the area, and the number of individuals in each quadrat is counted.
12
Q
What is the equation to work out population size?
A
Number of organisms in all quadrats ✖️ total size of an area where organisms live ➗ total area of quadrats
13
Q
What is a food web?
A
A food web shows the feeding relationships between the organisms in a community.
14
Q
What can we use a food web for?
A
To predict what will happen if there are any changes in the ecosystem.
15
Q
What is the order of a food web?
A
Producer Primary consumer/ herbivore Secondary consumer/ carnivore/ predator Tertiary consumer/ carnivore/ predator Top predator
16
Q
Each year, over the whole earth, photosynthesis capture 3 X 10 to the power of 20 J of energy transferred by light from the sun. Much of this energy is transferred to substances in new plant biomass (the mass of tissues). Where is the rest transferred to?
A
The rest is transferred to the environment by heating, during processes such as respiration. Other organisms cannot make use of energy transferred to the environment by heating and so these energy transfers are less useful for living things.
17
Q
Describe trophic levels
A
Energy is stored in plant (producer) biomass when it is transferred to a herbivore (primary consumer). The energy stored in the herbivore is then transferred to the carnivore (secondary consumer) that eats it, and so on through the trophic levels (feeding levels) of a food chain. We can this of this as energy flow though the biotic components of an ecosystem. At every trophic level the energy decreases, as some energy is wasted. At every trophic level the consumer needs to eat more to make up for the lost energy.
18
Q
How can you show the energy transfers of an organism?
A
Through a sankey digram
19
Q
What equation do you use to calculate the efficiency of energy transfers?
A
Energy transferred to biomass ➗ total energy supplied to organism
Efficiencies are usually given on a scale from 0-1 with 1 being complete efficiency. These values can be converted to percentages by multiplying by 100.
20
Q
If we measure the biomass of all the organisms at each trophic level in an ecosystem, what can we display it in?
A
A pyramid of biomass. This kind of diagram usually has a pyramid shape because energy is transferred from the food chain to the environment at each trophic level. With less energy available, less biomass can be produced. We can calculate the percentage transfer of biomass between tropic levels in a pyramid of biomass. There is a maximum length of food chain in an ecosystem. The pyramid shape helps to explain why there is a limit. The energy stored in the biomass of the top trophic level is too little to support another level.
21
Q
The distribution of organisms is where they are found in an ecosystem. What can distribution be affected by?
A
Distribution can be affected by physical and chemical factors, such as temperature, rainfall and substances in the soil. These non-living factors are called abiotic factors. The effect of abiotic factors on the distribution of organisms can be measured using a belt transect. If abiotic factors change, then the distribution of organisms may also change.
22
Q
Quadrats are placed along a line in a habitat, and the abundance of organisms is measured as well as the abiotic factors in each quadrat position. What does changes in abundance show?
A
Changes is abundance can show which abiotic factor has the greatest effect on the organisms.
23
Q
Each species of organism has certain adaptations, what does this mean?
A
The organism is suited to particular conditions.
24
Q
What are the consequences of of climate change on organisms?
A
Few organisms can survive drought (lack of water) for long. Most land plants cannot survive if their roots are under for long. If the climate changes resulting in more flooding or more drought, then many species in different communities may die out.
25
How do temperatures affect the distribution of organisms?
All organism have adaptations that make them suited to life at particular temperatures. A long-term rise or fall in temperature in an ecosystem will change the distribution of some organisms and so affect the whole community.
26
Light is essential for plants and algae to grow.
In the oceans, most algae can only get enough light within 30m of the surface. On land, light is limited within forests. In dense forests, few plants can grow on the forest floor.
27
Substances that cause harm in the environment are pollutants and cause pollution. Many human activities release pollutants. What are the effects of this?
These can poison organisms or cause harm to organisms in other ways (such as plastics being eaten by fish and other organisms).
28
Describe the method of the core practical - quadrats and transects.
Peg out a long tape measure (at least 20m) on the ground, starting where there is no shade and ending in heavy shade. This is the transect line.
You will need to make measurements at regular intervals along the transect line. Decide on you measure meant intervals, which may depend on how long the line is and how much time you have to record information.
Measure the abiotic factors at each point and record them.
Record the abundance of your selected plants in the quadrat.
Repeat till you get to the end of you transect line.
29
What are biotic factors?
Living organisms in an ecosystem, they affect other living organisms
30
How do biotic factors affect each other?
Organisms have to compete with each other for food.
Some organisms eat each other.
There is lots of competition in the ecosystems.
31
Go to page 184
And read it
32
In large communities, many biotic factors may affect predator and prey numbers. However in small communities, the number of a predator and its prey may be closely related in its what?
Predator-prey cycle
33
What is a predator-prey cycle?
The regular variation in numbers of predator and prey within a feeding relationship
34
What is biodiversity?
The variety of species in an area.
35
What is lecanora conizaeoides?
It is a specie of lichen that grows on trees and buildings. Like all lichens, it is a mutualistic relationship between a fungus and an alga. Until about the last 20 years, it was the only lichen found in city centres and industrial areas. This is because it is the only lichen that can tolerate air polluted with sulfur-containing gases from burning fossil fuels. So this lichen can be used as an indicator specie for sulfur dioxide pollution in the air.
36
Over the past 50 years, there has been a large fall in sulfur dioxide pollution in the air, and this has affected where the lichen lecanora conizaeoides is found. Why has the distribution of other lichen species also changed?
Because the levels of other pollutants have changed.
37
What is blackspot fungus and what does it indicate?
Blackspot fungus is a pathogen of roses and it indicates air pollution. The fungus cannot grow well where there is a lot of sulfur pollution. So, roses growing in cities rarely suffered from blackspot infection.
38
What can water pollution be caused by!
Poisonous substances released by factories such as mixers or detergents. Also fertilisers and sewage.
39
How are some aquatic species of invertebrates useful pollution indicators?
Substances in the pollution cause eutrophication, which encourages the rapid growth of algae and plants. The bacteria that feed on the dead plants and algae then reduce the oxygen concentration in the water, which kills many animals. Different aquatic invertebrates are adapted to different concentrations of oxygen.
40
How can water and air pollution be measured?
Using sensors. These give numerical data at the time of the measurement. Pollution indicator species do not give this level of detail in measurement, but they are useful as a simple assessment of the long-term health of an ecosystem.
41
What is parasitism?
It is a kind of feeding relationship where a parasite benefits by feeding off a host organism, causing harm to the host. The parasite lives in or on the host. The host may survive for a king time and continue to provide food for the parasite if the parasite causes limited harm.
42
Some parasites, such as lice, live in the outside of their hosts. Others such as tapeworms, live inside. What do all parasites have to help them survive in or on their host.
Adaptations
43
What are the adaptations do tapeworms have to live inside their host?
Hooks and suckers attach the worms head firmly to the hosts intestine wall.
Segments contain male and female sex organs so fertilisation can occur.
A flattened body allows absorption of nutrients over a whole surface without need for digestive or circulatory systems.
44
What adaptations do headline have to live on their host?
Sharp mouthparts can pierce skin and suck blood.
Sharp claws grip on to hair and skin.
Eggs are glued to hairs to prevent them falling off.
45
What is a mutualistic relationship?
A relationship where organisms live together to benefit each other. Eg many flowers depend on insects for pollination. The flower benefits by being ab,e to produce fertilised egg cells, and the insect benefits by collecting nectar or pollen from the flower which it needs for food.
46
How do sea anemone's and clownfish have a mutualistic relationship?
A sea anemone's stinging tentacles protect clownfish from predators. Clownfish chase off the predators of the anemone and provide nutrients in their faeces, which help the anemone to grow.
47
How do coral polyps and single-celled algae have a mutualistic relationship?
The algae can live in the water surrounding the corals, but are better protected inside a polyp. The algae photosynthesise and share the food they make with the coral animal.
48
What does eutrophication mean?
The addition of more nutrients to an ecosystem than it normally has.
49
How much of the protein eaten by people globally comes from fish?
17%
50
What has over fishing wild fish stocks done?
It has damaged some aquatic ecosystems.
51
What does fish farming aim to do?
Fish farming aims to produce more fish and so reduce overfishing of wild fish.
52
What are the problems of fish farming?
The problem is so many fish are kept in a relatively small space. Uneaten food, and faeces from the fish, sinks to the bottom of the water. This can change conditions, which may harm the wild organisms that live there. Parasites and disease spread more easily between fish in pens, so the fish need to be treated to keep them healthy.
53
What can introducing new species to ecosystems do?
It can affect the indigenous, or native, species (organism that have always been there).
54
What does indigenous mean?
Organisms that have always been in an area. Another word for native.
55
What does non-indigenous mean?
Organisms that have been introduce to an area where they haven't been before.
56
Why are some species introduce into an ecosystem?
In order to effect the ecosystem, such as to reduce the numbers of another specie that has got out of control. This often happens after humans have changed ecosystems and affected the food web.
57
What is eutrophication?
It is the addition of more nutrients to an ecosystem than it normally has.
58
Describe the steps of how eutrophication can affect an aquatic ecosystem
Fertiliser is added to plants by a river.
Rain washes the fertiliser off and nitrates and phosphates are washed into the river.
High nitrate and phosphate concentrations in the water encourage plants and algae to grow rapidly.
Surface plants block sunlight so plants in the water die and stop producing oxygen through photosynthesis.
Bacteria that break down dead materials increase in numbers and use up more oxygen from the water.
Aquatic animals such as fish die due to a lack of oxygen.
59
What is reforestation?
Planting new forests where old forests had been knocked down.
60
What is conservation?
The protection of an area or species to prevent damage.
61
What does endangered mean?
An area or species that are at risk of distinction.
62
Give two ways of preserving biodiversity
Reforestation and conservation
63
Which forest in northern England was reforested?
Kielder forest
64
When is conservation of a species easier?
When the habitat is also protected. However the habitats of many rare species are being damaged or destroyed. For example tigers live in dense forests which are being cut down for wood and to create space for people to live.
65
Why do people hunt tigers?
For fur and other body parts, and to reduce attacks on farm animals.
66
Why are tigers being bred in captivity?
To increase their numbers, but their habitats need to be rebuilt and protect too. These habitats also need to be linked so that tigers can roam more widely and find mates.
67
Why is preserving biodiversity so important?
For conserving individual species or communities. And areas with greater biodiversity can recover faster from natural disasters such as flooding. We also use plants and animals for food and as a source of medicines and other products. As conditions change, we may need new varieties of plants and animals to provide what we need. So it is important that we try to preserve as many species as we can.
68
What does food security mean?
Food security means having access to enough safe and healthy food at all times.
69
What has increased food security in many places?
Improving agricultural methods such as using fertilisers and more productive varieties and breeds.
70
Where is food security an issue?
In very poor counties or where there's conflict.
71
Why may the food security issue become more difficult?
Because of the rising global human population. In 1960 there were just over 3 billion people and today there is 7.5 billion.m
72
Generally as countries become wealthier, people prefer to eat more meat and fish. Give ways this affects the environment
Eg, up to 15 times more protein is produced from soybean than from animals (meat), on the same area of land. Changing farming practices, such as eating farmed rather than wild fish (there are more farmed fish than wild fish) can help the environment. However, some people think we should replace meat and fish preteen with more vegetable protein to help protect the environment.
73
Growing foods from crops causes problems, particularly with agricultural inputs such as fertilisers. Why?
Fertilisers increase plant growth and the yield of crops. Over the past 50 years there has been a 700% increase in the amount of fertilisers used globally each year. Most of this fertiliser is made using chemical processes that need energy and releases carbon dioxide. This raises concerns about sustainability. (If a process is sustainable, it is possible to continue it at the same level without causing harm to the environment or to food security.
74
Increasing carbon emissions from many human activities are leading to climate change. What can this lead to?
This can lead to pests and pathogens moving into new areas. Eg, midges, which are vectors for the virus that causes bluetounge disease, are killed by cold temperatures. Bluetounge disease was first seen in the UK in a cow, in 2007. Since then, it has spread to sheep and other cattle across the country.
75
What was an idea to reduce carbon emissions?
One idea to reduce carbon emissions is to grow plants for biofuels to replace fossil fuels. The carbon released by burning a biofuel is no key the amount removed from the air by the crop as it grew. In 2013, 0.8% of land in the UK that could have grown crops was used to grow biofuels, and this proportion is increasing. This raises other sustainability issues, of whether land should be used to grow food or fuel.
76
What are biofuels?
Fuel produced from biomass
77
What is biomass?
The total mass in living organisms, usually shown as the mass after drying.
78
What different substances do living organisms need to stay alive?
Water, carbon and nitrogen compounds. There are only limited amounts of these substances on earth, so they must be recycled through organisms and the environment in order to support life.
79
Describe the steps of the water cycle
Groundwater (water from rocks and soil) goes into rivers, lakes and oceans.
Rivers flow into lakes and eventually returns to the oceans.
Water evaporates from oceans lakes and rivers to for, water vapour.
As air rises it cools, so water vapour in it condenses to form clouds.
As water droplets get too large and heavy they fall as rain or snow.
80
Go to page 196
And look at the water cycle
81
Describe organisms and water
Water names up the majority of most organisms body mass. Around 60% of your body is water. Much of the cell cytoplasm is 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. Humans can only survive a few days without water.
82
There is plenty of fresh water in the environment, such as in rivers, lakes and underground. We can use this water for washing but how do we make it potable (safe for drinking)?
To make it potable, the water must be treated with chemicals and filtered, to remove dirt, pathogens and any toxic substances (such as some metal ions). The water may also be treated to improve the taste, by removing other non-toxic materials.
83
Where must drinking water be collected in places of drought?
From the air or extracted from sea water.
84
What is obtaining fresh water from the sea or salty water known as?
Desalination. Several methods are used to do this, including distillation where water is evaporated and then condensed and collected.
85
What is desalination?
A process that produces fresh drinking water by separating the water from the salts in salty water.
86
What is distillation?
The process of separating a liquid from a mixture by evaporating the liquid then condensing it (so that can be collected).
87
Describe the process of desalination
Dirty water is put out in the sun.
Water evaporates as it gets hotter inside the still.
Water condenses.
Clean water is collected.
88
Go t page 197
And look at desalination
89
Describe how reverse osmosis can be sued to make potable water
Reverse osmosis is the movement of water particles moving from a low water potential to a high water potential across a semi-permeable membrane against the concentration gradient. Reverse osmosis uses applied pressure to get fresh water.
90
What is the carbon cycle?
A sequence of processes by which carbon moves from the atmosphere, through living and dead organisms, into sediments and into the atmosphere again.
91
Carbon dioxide molecules in the atmosphere diffuse into plant leaves. What happens inside a leaf?
Photosynthesis may cause the carbon atom in the molecule to become part of another carbon compound, called glucose.
92
If glucose is used by a plant for respiration what will happen?
The carbon atom will become part of carbon dioxide again and be released back into the atmosphere. Alternatively, the glucose may be changed into other carbon compounds and used to make more plant biomass.
93
Carbohydrates, fats and proteins in all plants all contain carbon atoms. What happens when an animals eats a plant?
When an animal eats a plant, some of these compounds are digested and taken into its body. The rest will leave the animals body in faeces.
94
In an animal, what are some of the absorbed carbon compounds used for?
Some of them are used for respiration and some form waste products that are excreted in urine. The rest are used to build more complex compounds in the animals tissue, making more animal biomass. If the animal is eaten by a predator, the same process happen again.
95
If plants and animals are not eaten and just die, their bodies are broken down by decay. What is decay caused by?
Decay us caused by microorganisms that we call decomposes. Decomposers include fungi and bacteria, which also break down the carbon compounds in animal waste.
96
What do decomposes use carbon compounds they absorb for?
For respiration and to make more complex compounds in their cells. When they die, they will be decayed by other decomposes. If many large dead plants are buried so quickly that decomposes cannot feed on them, them over millions of years they may be changed into pest or coal by heat and pressure form the earth. In the same way, oil and natural gas are formed from dead microscopic sea plants and animals.
97
Coal, peat, oil and natural gas are fossil fuels, as they contain carbon compounds that were living organisms millions of years ago. What does Burning fossil fuels do?
It releases carbon back into the atmosphere as carbon dioxide.
98
What is the movement of carbon through the biotic and abiotic components of the environment called?
The carbon cycle
99
Go to page 199
And look at the carbon cycle
100
What does decay mean and what are decomposers?
Decay is a process in which complex substances in dead plant and animal biomass are Brocken down by decomposers into simpler substances and a decomposer is an organism that feeds on dead material causing decay.
101
Go to your exercise book
And look at the carbon cycle and practice drawing it
102
What is nitrogen?
Nitrogen is an unreactive gas that makes up around 80% of the atmosphere. Around 3% of your body is composed of nitrogen compounds.
103
Describe nitrogen in plants
Plants contain nitrogen compounds in proteins and DNA. To grow well, plants need nitrogen to make more of these compounds. They cannot use unreactive nitrogen from the air. Instead they absorb nitrogen compounds such as nitrates that are dissolved in water.
104
Describe how soil fertility is maintained by decomposers such as bacteria in the soil
These organisms release nitrogen compounds together with carbon compounds when they decompose dead plants and animals in their waste.
Farmers make use of this decay process when they add manure (which includes animal waste) to their fields. Farmers may also spread artificial fertilisers onto fields to increase the soil fertility. The nitrogen compounds in fertilisers are soluble and dissolve in soil water.
105
What is nitrogen-fixing bacteria?
It's a bacteria that can convert nitrogen gas into ammonia and nitrogen compounds in the soil. It also creates proteins, nucleic acid and helps plant growth. Some plants such as peas and beans have a mutualistic relationship with this bacteria, the bacteria are protected inside nodules in the plant roots, and the plants get nitrogen compounds directly from the bacteria.
106
How can farmers make use of nitrogen-fixing bacteria to keep their soil fertile?
By planting a crop of peas (or related plants) and then digging in the roots after the crop has been harvested. The following year, a different crop will benefit from the additional nitrogen compounds in the soil. Planting a sequence of crops in different years, such as wheat followed by potatoes followed by peas. This is called crop rotation.
107
What is the nitrogen cycle?
A sequence of processes by which nitrogen moves from the atmosphere through living and dead organisms, into the soil and back to the atmosphere.
108
What do decomposers do?
They convert nitrogen compounds, dead matter and urea into ammonia in soil.
109
What does nitrifying bacteria do?
It converts ammonia in soil to to nitrates in soil.
110
What does denitrifying bacteria do?
It converts nitrates in the soil to nitrogen gas in the atmosphere.
111
Study the nitrogen cycle in exercise book
And practice drawing it
112
Usually the soft tissues of organisms are decayed soon after death. What are they broken down by?
By decomposers, these microorganisms grow best in warm and moist conditions, and many need oxygen.
113
Decay can cause problems, particularly with keeping food fresh. What do most methods of food preservation rely on?
Reducing temperature, for examples in fridges and freezers.
Reducing water content, for example by salting and then drying meat to make ham or salami.
Irradiation of packaged food to kill decomposers.
Reducing oxygen, for example storing foods in oil. Foods that easily decay (eg salad leaves) are often packaged in an unreactive gas, such as nitrogen.
Vegetables could be put in oil or vinegar and fruit in sugar syrup.
114
The effects 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. What does compost contain?
The compost contains many of the nutrients that were in the plant tissues. However, the decay process leaves them in a form that makes it easier for plants to absorb. Spreading compost on a garden increases soil fertility. The way a compost heap is constructed affects the conditions inside the heap, and so affects the rate of compost formation.
115
What is compost?
Waste vegetable material that has been decomposed, for use in increasing fertility of garden soil.
116
What is the equation to work out the rate of decomposition?
Rate of decomposition = mass lost ➗ number of days
117
What is the best temperature for decomposers?
37°c after that temperature the enzymes will be denatured.
