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Biology Final Flashcards GCSE > Topic 7 - Ecology > Flashcards

Topic 7 - Ecology Flashcards

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1
Q

What is compost

A

-Decomposed organic matter that is used as a natural fertiliser for crops and garden plants. Farmers and gardeners try to provide the ideal conditions for quick decay to make compost.

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2
Q

What is responsible for decomposition and why does it affect rate of decay

A

-Microorganisms such as bacteria and fungi as well as detritus feeders (other animals) feed on dead things.
-The conditions have to be just right for them to work at the fastest rate

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3
Q

How does temperature affect rate of decay

A

-Warmer temperature make things decompose quicker because they increase the rate that the enzymes involved in decomposition work at, as enzyme substrates have more kinetic energy so there are more collisions and therefore a faster rate of decomposition. If it’s too hot, decomposition slows down or stops because the enzymes are destroyed and the organisms die. Really cold temperatures slow the rate as well.

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4
Q

How does oxygen availability affect the rate of decay

A

-Many organisms need oxygen to respire which they need to do to survive. However the microorganisms involved in anaerobic decay don’t need oxygen.

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5
Q

How does water availability affect rate of decay

A

-Decay takes place faster in moist environments because the organisms involved in decay need water to carry out biological processes and is needed to absorb products of digestion

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6
Q

How does the number of decay organisms affect the rate of decay

A

The more microorganisms and detritus feeders there are, the faster decomposition

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7
Q

What is biogas made up of

A

Mainly methane which can burned as a fuel

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8
Q

What produces biogas

A

-Microorganisms which decay plant and animal waste anaerobically which produces methane gas.
-Sludge waste from sewage works or sugar factories is used to make biogas on a large scale.

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9
Q

Where is biogas produced and what conditions are needed

A

-In a simple fermenter called a digester or generator
-Biogas generators need to be kept at a constant temperature to keep the microorganisms respiring away.

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10
Q

Why does biogas need to be used straight away and what as

A

-It can’t be stored as a liquid as it needs too high pressure
-Used for heating, cooking, lighting or to power a turbine/generate electricity

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11
Q

What are the two main types of biogas generator

A

Batch generators and continuous generators

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12
Q

What are batch generators

A

-Make biogas in small batches
-They’re manually loaded up with waste, which is left to digest and the by-products are cleared away at the end of each session

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13
Q

What are continuous generators

A

-Make biogas all the time time
-Waste is continuously fed in, and biogas is produced at a steady rate. Continuous generators are more suited to large-scale biogas projects

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14
Q

What does a simple biogas generator need

A

-An inlet for waste material to be put in
-An outlet for the digested material to removed through
-An outlet so that the biogas can be piped to where it is needed

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15
Q

Outline the investigation for effect of temperature on the rate of decay

A
  1. Measure out 5cm^3 of lipase solution and add it to a test tube and label it L.
  2. Measure out 5cm^3 of milk and add it to a different test tube
  3. Add 5 drops of phenolphthalein indicator to the tube containing milk
  4. Then measure out 7cm^3 of sodium carbonate solution and add it to the tube containing milk and phenolphthalein. This should make the solution alkaline so it should turn pink
  5. Put both tubes into a water bath set to 30°C and leave them to reach the temperature of the water bath. You could stick a thermometer into the milk tube to check this.
  6. Once the tubes have reached 30°C use a calibrated dipping pipette to put 1cm^3 of the lipase solution into the milk tube and start a stopwatch straight away.
  7. Stir the contents of the tube with a glass rod. The enzyme will start to decompose the milk
  8. As soon as the solution loses it pink colour stop the stopwatch and record how long the colour change took in a table
  9. Repeat the experiment at a range of different temperatures and do at least 3 tests for each, then calculate the mean time taken for colour change to occur at each temperature
  10. Then use the results to calculate the rate of decay using this formula. The units will be s^-1 since rate is given per unit of time.
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16
Q

How to calculate rate

A

Rate = 1000/time

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17
Q

What is the independent variable for the rate of decay practical

A

The temperature

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18
Q

What is the dependent variable for the rate of decay required practical

A

Time for indicator to change colour

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19
Q

What are the possible control variables for the rate of decay required practical

A

Initial volume and concentration of lipase and fat in the milk

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20
Q

What are abiotic factors

A

Non-living factors in an ecosystem

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21
Q

Give some examples of abiotic factors

A

-Moisture level
-Light intensity
-Temperature
-Carbon level (for plants)
-Wind intensity and direction
-Oxygen level (for aquatic animals)
-Soil pH and mineral environment

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22
Q

What can an increase or decrease in an abiotic factor cause

A

A change in the environment (such as temperature) which can affect the size of populations in a community. This means they can also affect the population sizes of other organisms that depend on them

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23
Q

Give an example of an abiotic factor decreasing that will affect a population

A

-A decrease in light intensity, temperature or level of carbon dioxide could decrease the rate of photosynthesis in plant species. This could affect plant growth and cause a decrease in the population size.

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24
Q

Give an example of an biotic factor decreasing that will affect a population

A

A decrease in the mineral content of the soil could cause nutrient deficiencies this could affect plant growth and cause a decrease in the population size

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25
Q

What are biotic factors

A

Living factors

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26
Q

Give some examples of biotic factors

A

-New predators arriving
-Competition - one species may outcompete another so that the numbers are too low to breed
-New pathogens
-Availability of food

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27
Q

How could the introduction of a new biotic factor affect the environment

A

It may cause a change such as a new predator or pathogen. These changes can affect the size of populations in a community, which can have knock-on effects because of interdependence.

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28
Q

Give examples of an introduction of a biotic factor that could change an environment

A

-A new predator could cause a decrease in the prey population
-For example red and grey squirrels live in the same habitat and eat the same food but grey squirrels outcompete the red ones so the population of red squirrels is decreasing

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29
Q

What do food chains always start with and what do they do

A

A producer - which produce their own food using energy from the Sun

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30
Q

What usually are producers in a food chain

A

Green plants or algae which make glucose by photosynthesis

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31
Q

What can glucose be used for after a plant has produced it and how does this effect food chains

A

-To make other biological organisms in the plant these are the plants biomass - the mass of living material (energy stored in a plant)
-The energy is transferred through living organisms in an ecosystem when organisms eat other organisms.

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32
Q

What is the order of a food chain

A

Producers are eaten by primary consumers which are eaten by secondary consumers. Secondary consumers are eaten by tertiary

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33
Q

What is an example of a food chain

A

Dandelions > feed rabbits > feed foxes

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34
Q

What is a predator

A

Consumers that hunt and kill other animals

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35
Q

What is prey

A

Animals that predators eat

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36
Q

What are stable communities with predators and prey

A

-The population of any species is usually limited by the amount of food available.
-If the population of the prey increases, then so will they population of the predators
-However as the population of predators increases, the number of prey will decrease
-Predator prey cycles are always out of phase with each other. This is because it takes a while for one population to respond to changes in the other population. E.g. when the number of rabbits goes up, the number of foxes doesn’t increase immediately because it takes time for them to reproduce.

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37
Q

Why would we investigate fields and the amount of organisms in certain areas

A

The distribution of where organisms are found is affected by environment, so an organism might be more common in one area than another due to differences in environment. (e.g. you might find daises more common in the open than under trees because there’s more light available in the open)

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38
Q

What are the two ways we can study the distribution of organism

A

-Measure how common an organism is in two sample area (e.g. quadrats) and compare
-Study how the distribution changes across an area (e.g. placing quadrats along a transect

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39
Q

What type of data does using quadrats and transects

A

Quantitative data about the distribution

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40
Q

Outline how to use quadrats to study the distribution of small organisms

A

-Place a 1m^2 quadrat on the the ground at a random point within the first sample area. (e.g. divide the area into a grid and use a random number generator to pick coordinates)
-Count all the organisms within the quadrat
-Repeat steps 1 and 2 as many times as you can
-Work out the mean number of organisms per quadrat within the first sample area.
-Repeat steps 1-4 in the second sample area
-Finally compare the two means (e.g. you might find 2 daisies per m^2 in the shade, and 22 daisies per m2 in the open field)

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41
Q

When using quadrats to study the distribution of small organisms why is it important to choose the grid reference at random

A

To avoid bias

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42
Q

When using a quadrat to study the distribution of small organisms how could you improve the accuracy of the estimate

A

Choose more squares

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43
Q

Instead using a quadrat to study the distribution of small organisms why wouldn’t a biologist count all the daisies on the field

A

Too time consuming

44
Q

Outline how to use transects to study the distribution of organisms along a line

A
  1. Mark out a line in the area you want to study using a tape measure
  2. Then collect data along the line
  3. You can do this by just counting all the organisms you’re interested in that touch the line
  4. Or you can collect data by using quadrats these can be placed next to eachother along the line or at intervals (e.g. every 2m)
45
Q

When using a transects to study the distribution of organisms along a line why would you use a percentage cover

A

It may be difficult to count all the individual organisms in the quadrat (e.g. if it’s grass). So estimate the percentage area of the quadrat covered by a particular organism (e.g. by counting the number of little squares covered by the organism) (more than half of the square has to be covered)

46
Q

What is a transect

A

A line used to help find out how organisms are distributed across an area

47
Q

What are trophic levels

A

The different stages of the food chain that consist of one or more organisms that perform a specific in the food chain

48
Q

What does trophic level 1 contain

A
  1. Producers are the organisms at the starting point of a food chain e.g. plants and algae
  2. They’re called producer because they make their own food by photosynthesis using energy from the Sun
49
Q

What does trophic level 2 contain

A
  1. Herbivores that eat the plants and algae are primary consumers
  2. Herbivores eat only plants and algae
50
Q

What does trophic level 3 contain

A
  1. Carnivores that eat the primary consumers are secondary consumers
  2. Carnivores are meat eaters
51
Q

What does trophic level 4 contain

A
  1. Carnivores that eat other carnivores (secondary consumers) are tertiary consumers
  2. Carnivores that have no predators are at the top of the food chain so they’re the highest trophic level and known as apex predators.
52
Q

What do decomposers do

A
  1. Bacteria fungi and detritus feeders play an important role in ecosystems
  2. They decompose any dead plant or animal material left in an environment
  3. They can do this by secreting enzymes that break the dead stuff down into small soluble food molecules which then diffuse into the microorganisms
  4. This also releases nutrients into the environment which producers need to grow
53
Q

How do pyramids of biomass work

A
  1. Each bar on a pyramid of biomass shows the relative mass living material at a trophic level (how much all of the organisms as that level would weight all together)
  2. The bar at the bottom always represents the producer, the next bar up will be the primary consumer, then the secondary consumer and so on up the food chain.
  3. They are almost always pyramid shaped
54
Q

What do pyramids of biomass do

A

They show the biomass of each trophic level in a food chain

55
Q

How much energy is transferred up each trophic level

A

Only around 10%

56
Q

Why does only 10% of biomass get passed on by each trophic level

A
  1. Organisms don’t usually eat every part of the organism they’re consuming, for example some parts may be inedible (e.g. bone)
  2. Bits they do eat might not be absorbed if they can’t break them down properly, these parts will get egested as faeces
  3. Most of the glucose that animals absorb from the biomass is used to release energy through respiration so biomass gets released as waste products such as carbon dioxide and water. Urea is another waste product which is released in urine with water when the proteins in the biomass are broken down, so when the organism is eaten it doesn’t pass on all the biomass.
57
Q

When is biomass transferred through trophic levels

A

When organisms eat other organisms

58
Q

How do you calculate the efficiency of biomass transfer

A

Efficiency = biomass transferred to the next level / biomass that was available at the previous level x 100

59
Q

What is interdependence

A

Any major change in the ecosystem can have far reaching effects

60
Q

What are structural adaptations and give examples

A

-These are features of an organisms body structure such as shape or colour
1. Arctic animals have white fur for camouflage
2. Animals that live in cold places have a thick layer of blubber and a low surface area to volume ratio to help them retain heat
3. Animals that live in hot place have a thin layer of fat and a large surface area to volume ratio to help them lose heat

61
Q

What are behavioural adaptations and give an example

A

-The way organism behave
-Many species migrate to warmer climate during the winter to avoid the problems of living in cold conditions

62
Q

What are functional adaptations and give examples

A

-Things that go on inside an organism body that can be related to processes like reproduction and metabolism
1. Desert animals conserve water by producing very little sweat and small amounts of concentrated urine
2. Brown bears hibernate over winter. They lower their metabolism which conserves energy, so they don’t have to hunt when there’s not much food about

63
Q

What are extremophiles and give examples

A

-Microorganisms which are adapted to live in very extreme conditions
-For example some can live at high temperatures (e.g. super hot volcanic vents) and others can live in places with a high salt concentration (e.g. salty lakes) or high pressure (e.g deep sea vents)

64
Q

How does a change in the availability of water affect the distribution of organisms

A

-The distribution of some animal and plant species in the tropics changes between the wet and dry seasons.
-The times of year where there is more or less rainfall
(e.g. each year in Africa large numbers of giant wildebeest migrate moving north and back south as rainfall changes)

65
Q

How does a change in the temperature affect the distribution of organisms

A

-The distribution of bird species in Germany is changing because of a rise in average temperature. (e.g. the Europe bee-eater bird is a Mediterranean species but is now present in Germany)

66
Q

How does a change in the composition of atmospheric gases affect the distribution of organisms

A

-The distribution of some species changes in areas where there is more air pollution. (e.g. some species of lichen can’t grow in areas where sulphur dioxide is given out by certain industrial processes)

67
Q

Outline the water cycle

A
  1. Energy from the sun makes water evaporate from the land and sea, turning it into water vapour. Water also evaporated from plants (transpiration)
  2. The warm water vapour is carried upwards. When it gets higher up it cools and condenses to form clouds
  3. Water falls from the clouds as precipitation onto land, where it provides fresh water for plants and animals
  4. It then drains into the sea before the whole process starts again
68
Q

How are elements cycled by decay

A
  1. Living things are made of materials they take from the world around them which get passed up the food chain
  2. These materials are retuned to the environment in waste or when organisms die and decay
  3. Materials decay because they’re broken down by microorganisms. This happens faster in warm, moist, aerobic conditions because microorganisms are more active
  4. Decay puts stuff that plants need to grow back into the soil
  5. In a stable community the materials are taken out of the soil and used by plants are balanced by those that are put back in
69
Q

Outline the carbon cycle

A
  1. CO2 is removed from the atmosphere by green plants and algae during photosynthesis. The carbon is used to make glucose, which can be turned into carbohydrates, fats and proteins that make up the bodies of the plants and algae
  2. When the plants and algae respire, some carbon is returned to the atmosphere as CO2
  3. When the plants and algae are eaten some carbon becomes part of the fats and proteins in their bodies. The carbon moves through the food chain
  4. When the animals respire, some carbon is returned to the atmosphere as CO2
  5. When plants, algae and animals die, other animals and microorganisms feed on their remains. When these organisms respire, CO2 is returned to the atmosphere
  6. Animals also produce waste that is broken down by detritus feeders and microorganisms
  7. The combustion of wood and fossil fuels also releases CO2 back into the air
  8. So the carbon is constantly being cycled from the air through food chains and eventually back out into the air.
70
Q

What is the impact of the increasing population on the environment

A
  1. Puts pressure on the environment as we take resources needed for survival
  2. People around the world are demanding a higher standard of living so we use raw materials for luxuries which uses energy. This means we’re taking more resources quicker
  3. Many raw materials are being used up quicker than they’re bring replaced so one day we will run out
71
Q

How does water pollution affect the environment

A

-Sewage and toxic chemicals can pollute lakes, rivers and oceans, affecting the plants and animals that rely on them for survival. And the chemicals used on land can washed into water

72
Q

How does land pollution affect the environment

A

We use toxic chemicals for farming. We also bury nuclear waste underground, and we dump a lot of household waste in landfill sites

73
Q

How does air pollution affect the environment

A

Smoke and acidic gases released into the atmosphere can pollute the air (e.g. sulfur dioxide can cause acid rain)

74
Q

What causes global warming

A

-Gases in the atmosphere naturally act like an insulating layer. They absorb most of the energy that would normally be radiated out into space, and re-radiate it in all directions this increases the temperature of the planet
-The main greenhouse gases doing this are methane and CO2
-The earth is gradually heating up because of the increasing levels of greenhouse gases - this is global warming.

75
Q

How does global warming affect sea levels

A

-Higher temperatures cause seawater to expand and ice to melt, causing the sea level to rise. It has risen a little bit over the last 100 years. It it keeps rising it’ll be bad news for people and animals living in low lying places as it leads to flooding, resulting in the loss of habitats

76
Q

How does global climate affect the distribution of species

A

-As temperature increases and rainfall changes in different areas some species may become more widely distributed (e.g. species that thrive in warmer temperatures) Other species may become less widely distributed (e.g. species that need cooler temperatures may have smaller ranges as the conditions they thrive in exist in a smaller area)

77
Q

How does global warming affection migration

A

There could be changes in migration pattern (e.g. some birds may migrate further norther as more northern areas are getting warmer)

78
Q

How does climate change affect biodiversity

A

It could be reduced if some species are unable to survive a change in the climate so become extinct

79
Q

What do humans use land for and what affect does this have on the environment

A

-We use land for things like building, quarrying, farming and dumping waste
-This means there’s less land available for other organisms
-It could require deforestation or destruction of habitats like peat boggs

80
Q

What reasons are areas deforested

A

-To clear for farming to provide more food
-To grow crops from which biofuels based on ethanol can be produced

81
Q

How does deforestation cause less CO2 taken in

A

-Cutting trees means the amount of CO2 removed from the atmosphere during photosynthesis is reduced
-Trees lock up some of the carbon that they absorb during photosynthesis in their wood, which can remove it from the atmosphere for hundreds of years. Removing trees means that less is locked up

82
Q

How does deforestation mean more CO2 in the atmosphere

A

-CO2 is released when trees are burnt to clear land
-Microorganisms feeding on bits of dead wood release CO2 as a waste product of respiration

83
Q

How can deforestation cause less biodiversity

A

-Biodiversity is the variety of different species - the more species, the greater the biodiversity
-Habitats like forests can contain a huge number of different species of plants and animals, so when they are destroyed there is a danger of many species becoming extinct - biodiversity is reduced

84
Q

What are peat bogs

A

-Areas of land that are acidic and waterlogged. Plant that life in bogs don’t fully decay when they die because there not enough oxygen and the partly rotted plants gradually build up to form peat
-Carbon in the plants is stored in the peat instead of being released into the atmosphere

85
Q

What is peat used for

A

-Peat bogs are drained so the area can be used for farmland
-The peat is cut up and dried to use fuel
-Also sold to gardeners as compost

86
Q

How do peat bogs release CO2 into the atmosphere

A

-When they are drained it comes into more contact with air and some microorganisms start to decompose it. When these microorganisms respire, they use oxygen and release CO2 contributing to global warming
-CO2 is released when peat is burned as fuel
-Destroying the bogs destroys habitats so reduced biodiversity

87
Q

How do breeding programmes help biodiversity/ecosystem

A

Help prevent endangered species from becoming extinct. These are where animals are bred in captivity to make sure the species survives if it dies out in the wild. Individuals can sometimes be released into the wild to boost or re-establish a population

88
Q

How do programmes to protect habitats help biodiversity/ecosystem

A

-Habitats like mangroves, heathland and coral reefs have been started. Protecting these habitats helps to protect the species that live there preserving the ecosystem and biodiversity in the area.

89
Q

How do programmes that introduce hedgerows help biodiversity/ecosystem

A

-Hedgerow and field margins around fields on farms where only a single type of crop is grown. Field margins are areas of land around the edges of fields where wild flowers and grasses are left to grow. Hedgerows and field margins provide a habitat for a wider variety of organism that could survive in a single crop habitat

90
Q

How do programmes the government introduce help biodiversity/ecosystem

A

-Reduce the level of deforestation taking place and the amount of CO2 being released into the atmosphere by businesses. This could reduce the increase of global warming

91
Q

How does recycling help biodiversity/ecosystem

A

-People are encouraged to recycle to rescue the amount of waste that gets dumped in landfill sites. This could reduce the amount of land taken over for landfill, leaving ecosystems in place.

92
Q

How does money/cost create conflict for biodiversity maintaining

A

-It costs money. For example governments sometimes pay farmers a subsidy to reintroduce hedgerows and field margins. It can also cost to keep a watch on whether programmes and regulation are being followed. There can be conflict between protecting biodiversity and saving money may be prioritised for other things

93
Q

How do local people create conflict for biodiversity

A

Reducing the amount of deforestation will leave people unemployed which could affect the local economy

94
Q

How does food security create conflict for biodiversity maintaining

A

Sometimes certain organisms are seen as pests and are killed to protect crops and livestock so that more food can be produced. As a result the food chain and biodiversity can be affected.

95
Q

How is development creating a conflict for biodiversity maintaining

A

-It can affect the environment as land is in such high demand that previously untouched land with high biodiversity has to be used for development (housing or agriculture etc.)

96
Q

What can affect food security

A

-The world population is increasing and birth rate of LICS rising quickly
-As diets in developed countries change demand for certain foods to be imported from developing countries increases. Meaning that scarce food resources can become more scarce
-Farming can be affected by new pests and pathogen or changes in the environment conditions can result in the loss of crops and livestock leading to widespread famine
-The high input of farming can it make it too expensive for people in some countries to maintain food precautions so there sometimes aren’t enough people producing food in an area to feed the people
-In some parts of the world there are conflicts that affect the availability of food and water

97
Q

Why are fish stocks decreasing and what impact does this have

A

-Because we’re fishing so much
-This means there’s less fish for us to eat as the oceans food chains are affected and some species of fish may disappearing from the North West Atlantic

98
Q

How are fish stocks maintained

A

-Fishing quotas = there are limits on the number and size of fish that can be caught in certain areas. This prevents certain species from being overfished
-Net size = there are different limits of the mesh size of the fish net, depending on what’s being fished. This is to reduce the number of ‘unwanted’ and discarded fish - the ones that are accidentally caught (e.g. shrimp caught along cod. Using a bigger mesh size will let the unwanted species escape aswell as younger fish which can breed)

99
Q

How does limiting the movement of livestock and keeping them in a temperature controlled environment make farming more efficient

A

-Reduces the transfer of energy from livestock to the environment so more efficient, and more energy is available for growth so more food can be produced from same input of resources

100
Q

Give examples of some factory farming techniques

A
  1. Livestock likes calves and chickens are raised in small pens
  2. Fish can be in cages where their movement is restricted
  3. Some animals can be fed high protein food to further increase their growth
101
Q

Why is factory farming controversial

A

-The animals are kept so close close together disease can spread between them easily.
-There are also ethical objections, as some people think that making animals live in unnatural and uncomfortable conditions is cruel.

102
Q

Outline mycoprotein

A

-Using modern biotechnology large amounts of microorganisms can be cultured industrially under controlled conditions in large for use as a food source
-Used to make high protein meat substitutes for meals
-Made from the fungus Fusarium which is grown in aerobic condition on glucose syrup which it uses as food.
-The fungal biomass is harvested and purified to produce the mycoprotein

103
Q

How is bacteria engineered to produce human insulin

A
  1. A plasmid is removed from a bacterium
  2. The insulin gene is cut out of human chromosome using a restriction enzyme. Restriction enzyme recognise specific sequences of DNA and cut the DNA at these points. The cut leaves one of the DNA strands with unpaired bases - this is called a ‘sticky end’
  3. The plasmid is cut open using the same restriction enzyme - leaving the same sticky ends
  4. The plasmid and the human insulin gene are mixed together
  5. Ligase is added and joins the sticky ends together to produce recombinant DNA
  6. The recombinant DNA is inserted into bacterium
  7. The modified bacterium is grown in a vat under controlled conditions. You end up with millions of bacteria that produce insulin. The insulin can be harvested and purified to treat people with diabetes
104
Q

How can biotechnology help genetically modify crops

A

-Be produced to resist pests = improving crop yield
-Grow better in drought conditions = improving crops yield
-Modified to provide more nutritional value (golden rice produces chemical that’s converted in the body to vitamin A)

105
Q

Problems with biotechnology producing genetically modified crops

A

-Many people argue people go hungry as they can’t afford to buy food, not due to a shortage. They argue poverty needs to be tackled first.
-These are fears that countries may become dependent on companies who sell GM seeds
-Sometimes poor soil is the main reason why crops fail, and even GM crops won’t survive.

Biology Final Flashcards GCSE (3 decks)

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