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Biology Paper 2 > Ecology > Flashcards

Ecology Flashcards

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1
Q

How are communities created?

A

When many different populations interact in the same habitat
The populations are often dependent on each other

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2
Q

What is an ecosystem?

A

The interaction of a community with non-living (abiotic) parts of the environment

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3
Q

What do plants compete for?

A

Light,space,water and mineral ions

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4
Q

What do animals compete for?

A

Territory, food, water and mating partners

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5
Q

What is interdependence?

A

When organisms in a community depend on other organism for vital services to maintain a stable community

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6
Q

What do organisms depend on each other for?

A

Food,shelter,pollination, seed dispersal

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7
Q

What is affected when a species is added or removed

A

The population of other species, as it changes prey or predator numbers
Removing a species can make the whole ecosystem unstable

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8
Q

What is a stable community?

A

A community where all the biotic (living) and abiotic ( non living) factors are all in balance
Means populations sizes remain roughly constant and when a stable community is lost it’s very difficult to replace them
E.g tropical rainforests, oak woodlands, coral reefs

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9
Q

Why do organisms need a supple of material from their surroundings and other organisms?

A

To survive and reproduce

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10
Q

What are biotic factors?

A

Living factors that can affect a community

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11
Q

What are abiotic factors

A

Non living factors that can affect a community

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12
Q

Name abiotic factors and describe the effect of their changes

A

Light intensity- light is required for photosynthesis
Rate of photosynthesis affects rate at which plants grow
Pls to can be food sources or shelter for many organisms

Temperature- affects rate of photosynthesis

Moisture levels- both plants and animals need water to survive

Soil pH and mineral content- pH affects the rate of decay therefore how fast mineral ions returns to soil
Lack of minerals can stunt growth

Wind intensity and direction- wind affect the rate of transpiration
Transpiration affects temperature of plant and rate of photosynthesis

CO2 levels - affects the rate of photosynthesis
Also affects distribution of organisms as some thrive in high CoO2 environments

Oxygen levels - levels in water very unlike O2 levels in Sri
Most fish need high concentration of oxygen to survive

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13
Q

Name biotic factors that affect a community and describe the effect of their change

A

Food availability- more food means organisms can breed more successfully, so population increases

New predators- reduces population size of a specific prey species

New disease organisms (pathogens) - when new pathogen arises the population has no resistance to it so population decreases and could lead to extinction

Competition - if 1 species is better adapted to the environment than another, then it will outcompete it until the number of the lesser adapted species are insufficient to breed

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14
Q

What do adaptions enable organisms to do ?

A

To survive in the conditions where they live

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15
Q

Describe and name the different categories of adaptations

A

Structural- physical features, the shape or colour of a part of an organism e.g sharp teeth of a carnivore to tear meat, camouflage, species in cold environments have thick layer of fat for insulation

Behavioural - way an organism behaves ( actions it does) e.g basking in sun to absorb heat or energy, playing dead to avoid predators, migration, courting behaviour to attract mate

Functional- internal processes, involved in processes such as reproduction and metabolism e.g late implantation of embryos, conservation of water by producing little sweat

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16
Q

What are extremophiles?

A

Organisms that live in extreme conditions
These include high temperatures, pressures or salt concentrations
E.g bacteria which live in deep sea vents where pressure is very high (black smoker bacteria)

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17
Q

Give examples of different adaptions for different scenarios

A

Cold climate- smaller surface area to volume ratio- reduces heat loss
Lots of insulation (blubber/fat)

Dry climate- adaptions to kidneys so they can retain lots of water-producing very little urine
Being active in evenings or mornings when it’s cooler
Large SA to volume ratio - increase heat loss

Plant adaptations- curled leaves to reduce water loss, waxy cuticle- stops water evaporation
Water storing tissue in stem

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18
Q

Describe the different parts of a food chain

A
  • begins with a producer- these are always photosynthetic organisms (usually green plant or algae)- through photosynthesis they make glucose
    Glucose is used to make other biological molecules in plant which make up the biomass
  • producers are eaten by primary consumers- energy is transferred through organisms in an ecosystem when on is eaten by another
    -primary consumers are eaten by secondary consumers - animal eaten is prey and consumers that kill are predators
  • secondary consumers are eaten by tertiary consumers
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19
Q

How do u workout the distribution and abundance of species in an ecosystem

A

Tools called transects and quadrats are used
This information is then processed by calculating the mean, mode and median and then drawing a graph

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20
Q

What happens if the population of prey increases?

A

The population of predators will also increase resulting in the number of rod prey decreasing after some time as more would be consumed by increased number of predators
When there isn’t enough prey to feed all the predators, the population of predators decreases, allowing the population of prey to increase again

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21
Q

Describe the water cycle

A

Suns energy cause more water to evaporate forming water vapour, it’s also formed as a result of transpiration in plants
- water vapour rises and condenses to form clouds
- water returns to land by precipitation, this runs into lakes to provide water for plants and animals
- we breathe out water vapour
-this runs into seas and cycle begins again

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22
Q

Describe the factors which affect the rate of decomposition

A

Temperature- chemical reactions work faster in warmer conditions but if it’s too hot (above 45degrees) the enzymes denature, stopping decomposition
If temp is too low (0-4 degrees) bacteria will grow very slowly due to low enzyme activity and anything below this means bacteria can’t function

Moisture- needed to provide water to microorganisms as they grow faster in conditions with water because water is needed for respiration
Moisture is needed so they can reproduce and feed

Oxygen- microorganisms need in order to respire as most decomposers respire aerobically this is why decomposition occurs rapidly when there is plenty of oxygen

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23
Q

What do microorganisms produce when they decompose waste anaerobically?

A

Methane gas- can be burnt as a fuel

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24
Q

Describe the role of biogas generators and what they do

A

Produces methane
- waste is put in and the bacteria are allowed to carry out decomposition in controlled anaerobic conditions
- methane is then collected
- it uses waste materials to produce a renewable energy supply
- requires a constant temperature (30 degrees) so microorganisms keep respiring
- cannot be stored as liquid so needs to be used immediately

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25
Q

Describe the uses of decay process

A

-is used to make compost, a nutrient enriched fertiliser
- gardeners make this by using kitchen waste and garden plant materials
-farmers can make fertiliser by using by-products of harvesting fruits and vegetables by rotting down farmyard manure
- when compost returns to soil as fertiliser it provides valuable minerals and improves soil structure and water retention
- compost can be made with or without oxygen, with oxygen microorganisms will respire aerobically, releasing energy to their surroundings, killing weed seeds and speeding up decomposition process

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26
Q

Describe the carbon cycle

A

-CO2 is removed from air by photosynthesis by green plants and algae - they use CO2 to make carbohydrates, proteins and fats
They are eaten and the carbon moves up food chain
- CO2 is returned to air by plants, algae and animals respire.
Decomposers (group of microorganisms that break down dead organisms and waste) respire while they return mineral ions to soil
- CO2 is returned to air when wood and fossil fuels are burnt as they contain carbon from photosynthesis

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27
Q

Describe the required practical - effects of temperature on decay

A
  • can investigate this by measuring the pH change of fresh milk in the presence of enzyme lipase
  • make a solution of milk and cereal red indicator
  • add sodium carbonate which will cause solution to become alkaline and therefore appear purple
  • place tube in water bath at a specific temperature
  • add lipase enzyme and begin stop watch
  • time how long it takes for solution to turn yellow
  • repeat using different temperatures
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28
Q

In the practical why does indicator change colour to yellow when fatty acids are formed?

A

As solution becomes acidic

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29
Q

What are the control variables of practical?

A

Volume of lipase
Volume of milk
Volume of sodium carbonate solution
Volume of cereal red

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30
Q

What does environmental change affect?

A

The distribution of species in an ecosystem

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31
Q

What is environmental change caused by?

A

The seasons
Geographical position
Human interaction

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32
Q

Name 3 examples of environmental changes

A

Temperature- climate change may lead to insects migrating to places in world which are becoming hotter

Water availability- populations migrate to find water

Atmospheric gas composition1 certain pollutants can affect distribution of organisms

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33
Q

What is biodiversity

A

The variety of different species of organisms on earth or within an ecosystem

34
Q

Describe why waste management is important

A

Rapid growth in human population and increase in the standard of living means resources are used and more waste is produced
Unless waste and chemical materials are properly handled, more pollution will be caused

35
Q

Describe where pollution can occur

A
  • in water- from sewage, fertiliser or toxic chemicals
    Sewage- lots of bacteria so more aerobic respiration
    Fertiliser- causes growth of algae on surface which blocks light so plants die and decay
    Toxic chemicals - kill fish

In air- form smoke and acidic gases
Smoke- produces CO2, causes global warming
Acidic gases- bring fossil fuels released sulphur dioxide and forms acid rain
Is also formed by nitrogen oxides which are released from car exhausts

On land - from land fill and toxic chemicals
Landfill- rubbish that can’t be recycled is buried in ground
Toxic chemicals- soil in landfill sites becomes full of toxic chemicals eventually

36
Q

Define eutrophication

A

When fertilisers leach into ponds, rivers and lakes

37
Q

Define the stages of water pollution

A
  • fertilisers/ sewage are washed off land by rain
  • it ends up in freshwater ponds or rivers
  • plants (algae) grow rapidly on surface
  • bottom plants die and are decomposed by bacteria
  • decomposers use all the oxygen in water so other pond life dies
38
Q

What does it mean if an ecosystem has high biodiversity?

A

The ecosystem will be more stable as it’s better at withstanding environmental change
This is because there is reduced dependence of one species on another for food, shelter, physical environment

39
Q

Why is it important to maintain high levels of biodiversity?

A

To ensure ecosystems don’t collapse

40
Q

How are humans reducing/ having a negative effect on biodiversity?

A

More resources are being used and more waste is being produced
- more land is being used for houses, farming, shops, roads and factories which destroy habitats
- pollution kills plants and animals- sewage, fertiliser and toxic chemicals pollute the water
smoke and acidic gases pollute air- landfill and toxic chemicals result in pollution of land
- are using up raw materials quicker than they are being produced
-humans have only recently tried to reduce their impact

41
Q

Why is maintaining biodiversity important?

A

Future of humans on Earth depends on it
E.g for food and new medicines

42
Q

Describe different ways humans pollute land

A

Building- human population increases meaning more land is needed for human to live
So countryside ecosystems are destroyed to build homes and businesses

Quarrying- areas of land cleared to mine rocks and metals to meet demand of increasing building materials

Farming- large areas of land needed to grow commercial crops
Pesticides decreases biodiversity in farmlands

Landfill- land cleared and a hike is dug to place in unrecyclable waste

Peat bogs- are destroyed to make compost for homes
It kills plants, animals and bacteria ik this ecosystem

Deforestation- trees cut down to make space for farmland e.g rearing cattle for food

43
Q

When humans take up land how do they reduce the number of habitats for animals and plants?

A

By building, quarrying ( cutting into ground to obtain stones), farming and dumping waste

44
Q

Describe peat bogs

A
  • peat bogs are formed over thousands of years
  • peat is made from dead plants that haven’t decayed as there isn’t enough oxygen
  • these bogs are habitats for many species (migrating birds)
    -peat can be dried and used as fuel, this releases CO2
  • peat is used as compost, the compost will decompose and microbes will release CO2 in respiration- peat free composts should be encouraged
  • peat bogs are being destroyed- are being drained to create space for farming
  • it’s being used up quicker than it’s being farmed, as formation process is slow
45
Q

Define deforestation

A

The cutting down of a large number of trees in the same area in order to use the land for something else

46
Q

Why does deforestation occur in tropical areas?

A

To provide land for cattle and rice fields
To grow crops for biofuels which are used to produce energy

47
Q

Why does deforestation cause an increase in CO2 levels in atmosphere?

A
  • dead plant material is decomposed by bacteria that’s releases CO2 in respiration
  • photosynthesis removes CO2 from atmosphere
    -trees act as carbon sinks so less trees = more CO2
  • burning trees releases CO2 into atmosphere
48
Q

How does deforestation affect biodiversity?

A

Decreased biodiversity as number of habitats are reduced

49
Q

Describe random sampling techniques when using quadrats

A
  • place coordinates down 2 sides of the area to be sampled and use random number generator to decide where you are going to place quadrat

Person placing quadrat could be blindfolded spun around few times and the. Asked to walk set number of paces into sample area before placing down quadrat

50
Q

Why is random sampling used when using a quadrat?

A

To ensure data is representative and to reduce bias

51
Q

What is quantitative sampling?

A

Must have at least 10 reading in order to find the mean number of organisms per m squared

52
Q

Why do scientists use transect sampling?

A

To see how numbers of different organisms change as they move across a habitat

53
Q

What is a transect?

A

A line running across a habitat (rope or tape) used to mark out a sample area

54
Q

How is a quadrat used during transect sampling?

A

Quadrat is placed at multiple points along transect at specific distances apart
And organisms within quadrats are recorded

55
Q

Why is the process of using quadrats along a transect repeated?

A

To collect valid and representative results

56
Q

How do u workout population of species in a given area?

A

Population = mean per m squared x area of field

57
Q

What is global warming?

A

The temperature around the world is increasing as we are producing more greenhouse gases

58
Q

What is the greenhouse effect?

A

When gases in atmosphere (CO2 and methane) prevent some heat from sun reflecting into space and is instead absorbed and reflected back to Earth, heating it up as heat can’t escape

59
Q

What are the consequences of global warming?

A
  • glaciers/ ice caps melting - reducing habitats
  • rising sea levels- reduce habitats as low lying areas will be flooded with salty water
  • temperature and rainfall levels will affect migration and therefore the distribution of different species , as they can no longer survive where they live
  • extreme weather patterns
60
Q

How can we prevent the worst impacts of global warming?

A

Replace fossil fuels with renewable energy resources

61
Q

Describe how positive human interactions with ecosystems help to maintain biodiversity

A
  • maintaining rainforests- ensuring habitats here aren’t destroyed
  • reducing water pollution and monitoring the changes over time
  • preserving areas of scientific interest by stopping humans going there
  • replanting hedge rows and woodlands to provide habitats which were previously destroyed
62
Q

Describe how negative human interactions with ecosystems aren’t helping to maintain biodiversity

A
  • production of greenhouse gases levels leads to global warming
  • producing sulfur dioxide in factories- can lead to acid rain which will affect habitats
  • chemicals used in farming leak into environment
  • clearing land to build on, reduces number of habitats
63
Q

What programs have been put in place to maintain biodiversity and reduce our negative impact on ecosystems ?

A

Breeding programs - to stop endangered animals from becoming extinct

Protection and regeneration of rare habitats (coral reefs) - to stop species here becoming extinct
Regeneration will encourage populations to live here

Reintroduction of hedge rows and field margins around land where only 1 type of crop is grown - maintains biodiversity as hedgerows provide a habitat for lots of organisms and field margins provide areas where wild flowers and grasses can grow

Reduction of deforestation and CO2 production- reduced rate of global warming, slowing down rate habitats are destroyed

Recycling rather than dumping waste in landfill - reduces amount of land taken up for landfill, and slows the rate we are using to potential resources

64
Q

What are trophic levels and what are they represented by?

A

Are different stages in the food chain
Represented by numbers

65
Q

Describe the different trophic levels

A

Level 1 - organisms at first level are called producers (plants and algae)
They make their own food by photosynthesis

Level 2 - organisms at 2nd level are called primary consumers
Are herbivores

Level 3 - organisms are called secondary consumers
Are carnivores and they eat herbivores

Level 4 - organisms are called tertiary consumers
Are carnivores and they eat otter carnivores
Have no predators and are at the top of the food chain- apex predators

66
Q

What do decomposers do and how?

A

They break down dead plant and animal matter
Do this by secreting enzymes
The matter is broken down into small soluble food molecules and they move into microorganisms by diffusion

67
Q

What is biomass?

A

A measure of the total mass of living material in each trophic level

68
Q

What do pyramids of biomass show?

A

The relative biomass at each trophic level
There is less biomass as u move up trophic levels

69
Q

Why is approximately only 10% of biomass of each trophic level transferred to the next/ how is biomass lost by organisms at each trophic level?

A

Not all biomass can be eaten - generally carnivores can’t eat bone, hooves, claws and teeth

Some biomass will be lost from organism as waste products (CO2, H2O)

Some biomass is used in respiration to release energy for movement and maintenance of a constant body temp (lots of glucose used)

Some food that organisms ingests can’t be broken down properly so is excreted as faeces - herbivores don’t have all the enzymes to digest all the material they eat, so it’s egested instead

70
Q

How do I workout the efficiency of biomass transfers?

A

Efficiency = useful energy transferred/ original amount of energy x100

71
Q

Why is it common to find less animals in higher trophic levels?

A

As less biomass is transferred each time

72
Q

Define food security

A

Having sufficient food to feed the population

73
Q

What factors affect food security?

A

Increasing birth rate means more food is required

Changing diets in developed countries means food resources which are already in low amounts become even more scarce as the demand for them increases

New pests and pathogens destroy crops - transmission caused by the movement of people around world

Climate change affect food production- extreme weather patterns can affect crop growth from droughts to flooding

Conflict in some countries can affect the availability of sanitary food and water

74
Q

Describe methods farmers use to increase efficiency of food production

A

Done by reducing then energy transfer from animals to the environment:

Limit amount the animals move - keeping them in confined spaces reduces the need for respiration, less energy wasted

Controlling conditions the animals are kept in e.g temperature
Areas which have high temps mean less energy is water on maintaining body temperature

To increase growth animals are fed high protein foods

75
Q

What are the disadvantages of the methods used to increase efficiency?

A

Diseases spread rapidly within the population

Animal welfare issues - standard of living is low for the animals and their health is compromised

Costly- farmers will pay more for energy costs (heating and lighting)

76
Q

Why are the number of fish in oceans decreasing?

A

As humans are fishing at a faster rate than the population can regenerate

77
Q

What restrictions have been put in place to stop overfishing?

A

Net sizes must be a certain size (big) so smaller fish aren’t caught and can reach breeding age and produce more fish

Fishing quotas mean only a certain number of a species of fish can be caught to prevent overfishing and extinction

78
Q

What can biotechnology be used for?

A

To help feed the population and potentially provide treatments for a number of diseases

79
Q

Describe how new biotechnologies have been used in the medical and food industry

A

1) the fungus - fusarium- can produce mycoprotein
A protein-rich food source suitable for vegetarians
It’s grown in glucose syrup in aerobic conditions and the fungus is harvested and purified ready for consumption
Is protein without animals which reduces land use and methane production

2) genetically modified bacteria produces insulin
The insulin is taken and purified
Is used to treat people with diabetes

3) genetically modifying crops to have certain properties can have many advantages
Modifying them to be resistant to pests it extreme weather conditions increases yields
Modifying them to increase their nutritional value is beneficial in places where they lack access to certain vitamins (golden rice)

80
Q

Describe how the fungus fusarium can be grown to produce mycoprotein that can be eaten

A
  • large amounts of fusarium fungus are grown in sterile fermenters
  • water in tanks is kept at optimum temperature and pH for growth of the fungus. Oxygen and glucose are added
  • the Fusarium uses glucose to how and multiply, producing mycelia
  • mycelia are harvested and the mycoprotein is extracted from them
  • the protein is spun in a large centrifuge to remove water
  • then dried further and mixed with egg white and other flavourings to make a product that can be shaped and moulded

Biology Paper 2 (4 decks)

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