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GCSE Biology > Ecology > Flashcards

Ecology Flashcards

1
Q

What is meant by a habitat?

A

The environment in which an organism lives.

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2
Q

What is meant by a population?

A

The total number of organisms of the same species living in the same geographical area.

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3
Q

What is meant by a community

A

The population of all the different species that live in a habitat.

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4
Q

Biotic meaning?
Abiotic meaning?

A

Living parts
Non-living parts

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5
Q

Ecosystem meaning?

A

Both the abiotic and biotic parts of an environment and how they interact.

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6
Q

Living organisms have to compete for resources, this is because some resources may be in short supply and so are high in demand.

State the resources that organisms have to compete for:

A

PLANTS
- Light
- Space
- Water
- Mineral ions in soil

ANIMALS
- Territory
- Food
- Water
- Mating partners

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7
Q

What is meant by interdependence?

A

The concept that living organisms within an ecosystem rely on and interact with each other for various needs such as survival.

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8
Q

What is meant by a stable community?

A

One where all the species and environmental factors are in balance so that population sizes remain fairly constant.

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9
Q

Examples of interdependence x 3

A
  • Living organisms may depend on organisms such as trees for shelter.
  • Plants may depend on bees for pollination
  • Plants may depend on animals for seed dispersal through faeces,

This is why when a population of 1 species falls/increases, the whole community is affected.

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10
Q

Biotic factors which can affect a community are:

x4

A
  • Availability of food (if this falls, number of organisms in community will fall)

*New predators arriving (population of prey species (AND PREVIOUS PREDATORS due to competition) will fall)

  • The introduction of new pathogens; if this emerges and spreads it can wipe out the population of a species.
  • Competition - one species may outcompete another so much so the pop. of the outcompeted species falls until population are no longer sufficient to breed.

SUMMARY:

  • Pathogens
  • Food
  • Predators
  • Competition
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11
Q

Abiotic factors which can affect a community are:

x7

A
  • Light intensity (light is used for photosynthesis to produce food, if LI falls, rate of photosynthesis falls so rate of plant growth is reduced this will affect the population of animals which eat plants as food (decrease))

^less glucose produced to combine with nitrate ions in the soil.

  • Temperature (if temperature changes distribution of species may change - eg animals may migrate and plants may disappear/ stop growing)

^This affects the species which depend on them for food.

*Moisture levels (plants and species need water to survive - water is used for photosynthesis)

  • Soil pH and mineral content (plants cannot grow on soil that is too acidic or alkaline + need mineral ions eg nitrates to make amino acids for proteins)

*Wind intensity and direction (strong winds blowing in a certain direction eg inland from the sea may cause plants to lose water which will affect the rate of photosynthesis and reduce plant growth and affect herbivores)

(think about transpiration)

  • Carbon dioxide levels for plants (used for photosynthesis, if falls photosynthesis rate falls - which will affect population of plant as well as the herbivores)
  • Oxygen levels for aquatic animals (used for aerobic respiration, remains constant in air, but level of dissolved oxygen in water may fall which is harmful for aquatic organisms).

(Oxygen, CO2, mineral ion and soil pH, wind direction, light intensity, Temperature, Moisture levels)

^Think of photosynthesis, respiration and transpiration and the factors affecting these.

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12
Q

What is meant by a structural adaptation?

A
  • The body shape and structure
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13
Q

What is meant by a functional adaptation?

A
  • The body functions
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14
Q

What is meant by a behavioural adaptation?

A
  • The organisms behaviour
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15
Q

How are camels structurally adapted to living in dry conditions

A
  • Hump; this is a store of fat, fat is a thermal insulator, so all the fat being in one place allows for heat to be lost from other part parts of the camel’s body.
  • Thick coat on upper surface of the body - this insulates the top of the camel from the heat of the Sun and this also reduces water loss from sweating as it traps moisture.
  • Long eyelashes - keep dust out of their eyes.
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16
Q

How are camels functionally adapted to living in dry conditions?

A
  • Produce concentrated urine and dry faeces, this reduces water loss.
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17
Q

How are kangaroo rats behaviourally adapted to living in dry conditions?

A
  • Kangaroo rats are nocturnal so are active at night, this protects them from heat of the day
  • Stay in burrows during the day, this protects them from predators and keeps them cool
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18
Q

How are Arctic fox structurally adapted to living in cold conditions?

A
  • Thick fur - provides insulation and reduces heat loss to the air.
  • Small ears - smaller SA which reduces heat loss
  • White coat - camouflage, this helps it to hunt its prey.
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19
Q

How are cacti adapted to living in dry conditions?

A
  • Small leaves - reduce water loss (structural)
  • Extensive and shallow roots - allow cacti too catch as much water as possible after rain fall before water evaporates or sinks into the ground (structural)
  • Spines - protect cacti from animals (structural)
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20
Q

What is meant by an extremophile?

A

Organisms that lives one environments that are very extreme

eg
high temperature, pressure, or salt concentration.

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21
Q

Where can extremophiles be found and what organisms are they?

A

Bacteria (1) living in deep sea vents(1) are extremophiles.

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22
Q

FOOD CHAIN:

A
  • Producer
  • Primary consumer
  • Secondary consumer
  • Tertiary consumer
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23
Q

Why are producers important?

A
  • They synthesise complex molecules, (eg glucose from photosynthesis) and are the producers of biomass which is essential for life on Earth.
  • Biomass is passed down the food chain and is used as energy.

^^Glucose is an example of biomass
^^So producers provide organisms in a food chain with energy needed to support it.
^^Producers include green plants or alga which makes glucose by photosynthesis (any organism that can make food on its own).

**Photosynthetic are the producers of biomass for life on earth.

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24
Q

What is a primary consumer?

A

An organism that eats the producer

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25
Q

Secondary consumer:

A

Organism that eats the primary consumer.

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26
Q

Tertiary consumer:

A

Organism that eats the secondary consumer.

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27
Q

Predator:

A

Organisms that kill and eat other animals.

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28
Q

Prey:

A

Animals eaten by predators.

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29
Q

True or false, the population of predators and prey rise and fall in cycles?

A

True.

Prey pop inc = pred pop inc = prey pop dec = pred pop dec = prey pop increase ……….

  • This is only true in a stable community.
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30
Q

Producers:

A

PHOTOSYNTHETIC PLANTS (eg green plant; grass on land or algae/seaweed in the sea)

These are the producers of biomass which is essential for life on earth.

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31
Q

How are quadrats used to determine the abundance and distribution of species in an ecosystem?

A
  • They allow scientists to conduct random sampling to compare the numbers of organisms of different areas.
  • Quadrat - a wooden or plastic square
  • Quadrats are used to sample slow-moving organisms and plants.
  • Place on ground and count the no. of organisms inside it.
  • Quadrat is placed in random locations
  • Count number of each organism in quadrat
  • Repeat this many times at a large number of random locations
  • This is important as results will be valid because it is representative.
32
Q

Total population size =

A

(Total area/area sampled) x total number of species counted in that sample.

33
Q

When we calculate the mean do we include anomalous results?

A

NO.

34
Q

Describe the carbon cycle:

A

The Carbon Cycle includes two main processes, photosynthesis for carbon to enter the cycle, and respiration, for carbon to leave the cycle.

  • Carbon dioxide in the atmosphere is taken in by plants and algae for photosynthesis.
  • Some of the carbon is used to make carbs, fats and proteins which make up the cells of the plants and algae.
  • Some of the Carbon is also released back into the atmosphere as CO2 when plants and algae respire.
  • When plants and algae are eaten by animals, and these animals are eaten by other animals, the carbon that was in the plants becomes part of the carbs fats and proteins that is in the animals.
  • As animals respire some of the carbon is released as carbon dioxide into the atmosphere.
  • Animals release waste products such as faeces and eventually all the animals and plants die.
  • There is carbon in the waste products and in the dead remains.
  • The waste products and dead remains are broken down by decomposing microorganisms such as bacteria and fungi
  • As decomposers respire, the carbon in the waste and dead remains is returned back to the atmosphere as carbon dioxide and at the same time mineral ions are released into the soil.

EXTRA:

  • Under certain conditions eg lack of O2, decomposers cannot function effectively.
  • So carbon in dead remains is slowly converted into fossil fuels.
  • Humans have been burning huge amounts of these fossil fuels and releasing huge amounts of the carbon trapped within them back into the atmosphere.
35
Q

True or false, many different materials cycle through the abiotic and biotic components of an ecosystem?

A

True, these include water and carbon.

36
Q

Why are decomposers important?

A

They cycle materials throughout an ecosystem.

  • They help return carbon dioxide into the atmosphere.
  • They help return mineral ions into the soil.

Decomposers include fungi and bacteria.

37
Q

Carbon cycle definition:

A

The process by which carbon from organisms is returned to the atmosphere as carbon dioxide to be used by plants in photosynthesis.

38
Q

Describe the stages of the water cycle:

A
  • Energy from the Sun causes the water to evaporate from the surface of the sea.
  • The water vapour now travels into the air and cools down and condenses to form clouds.
  • The water in clouds then falls to the ground as precipitation (rain, hail sleet and snow).
  • When the water hits the ground some of it evaporates again back into the atmosphere.
  • Some of it passes into rocks to form aquifers.
  • A lot of the water form rivers or streams, and the water from rivers and streams eventually drain back into the sea.

HOW DO PLANTS AND ANIMALS CONTRIBUTE TO THE WATER CYCLE?

  • Plants take up water in their roots which moves up the plant in the xylem and passes out of the plant through the stomata as water vapour (transpiration)
  • Animals take in water when they drink it, and through their food, they then release it through exhalation, urine and their faeces.
39
Q

True or false, all forms of precipitation contain fresh water?

A

True - the salt isn’t evaporated with the water.

40
Q

Conditions for decomposition:

A
  • Warm temperatures (bc decomposers use enzymes to break down plant materials and enzymes work faster in warmer conditions - ensure the compost doesn’t become too hot, if it does the enzymes in the decomposers can denature and the decomposers can die)
  • Moist conditions (this is because chemical reactions that occur during decay require water)
  • Oxygen - needed for aerobic respiration for the decomposers to carry out aerobic respiration.
41
Q

Why are compost heaps warm anyway?

A
  • Bc decomposers which are breaking down the dead plants are releasing energy via respiration.
  • This energy is heat energy, which warms the compost.
42
Q

What does mixing the compost do?

A
  • Allows for more oxygen to be passed into the compost for aerobic respiration
  • Allows for the compost to be broken down into smaller clumps which increases the surface area for decomposers to act on.

COMPOST: A natural fertiliser used for growing garden crops or and plants.

43
Q

In the absence of oxygen, how do decomposers carry out decomposition?

A

Via anaerobic decay which produces a mixture of gases including methane - This is known as biogas (in many countries, biogas is used to provide fuel for homes)

*Decomposers produce biogas only under anaerobic conditions.

44
Q

What do environmental changes affect?

This includes environmental changes to:

  • Temperature
  • Availability of water
  • Composition of atmospheric gas.
A

They affect the distribution of species in an ecosystem.

These changes include:

  • Temperature
  • Availability of water
  • Composition of atmospheric gas

^^The distribution of species can depend on both abiotic and biotic factors. The factors above are examples of abiotic factors.

What can these changes be caused by?

  • Geographic factors ie in certain places = hotter
  • Seasonal factors = during summer = hotter
  • Human interaction = eg human activity can affect the levels of gases dissolved in water for instance with sewages being released into water, the levels of dissolved gases such as oxygen in the water will drop which may cause the population of species living in these condition that require O2 to fall.
45
Q

What is meant by biodiversity?

A

The variety of all the different species of organisms on earth, or within an ecosystem.

46
Q

Why is biodiversity important?

Biodiversity provides STABILITY to ecosystems.

A

A great biodiversity ensures the stability of ecosystems.

This stability is reached by reducing the dependence of one species one another for food, shelter and the maintenance of the physical environment.

47
Q

True or false?

Many human activities are reducing biodiversity and only recently have measures been taken to try to stop this reduction.

State 2 reasons why deforestation occurs

A

True

What do these human activities include?

Deforestation: why

-1 Land is used for rice fields or for grazing cattle
-2 Land is used to grow crops which is then used to make biofuels.

48
Q

Waste management and pollution:

A

Rapid growth in the human population and an increase in the standard of living mean that humans are using more resources and producing more waste which leads to pollution

Pollution can occur:
* in water, from sewage, fertiliser or toxic chemicals
* in air, from smoke and acidic gases
* on land, from landfill and from toxic chemicals.
Pollution kills plants and animals which can reduce biodiversity.

49
Q

Pollution can occur, unless:

A

Waste and chemical materials are properly handled.

50
Q

3 examples of how pollution can occur:

A

WATER POLLUTION:

  • when human faeces and urine in sewages are released into waterways such as rivers.
  • fertilisers from farms
  • Toxic chemicals being released from factories.

^these both cause the dissolved oxygen levels in waters to fall which kills aquatic organisms and reduce biodiversity

AIR POLLUTION:
- Smoke and acidic gases released from fossil fuels.
^this can kill plants and animals and reduce biodiversity.

LAND POLLUTION:
- Waste dumped on landfills destroys habitats for plants and animals.
- Toxic chemicals from landfills can leech onto the land and kill living organisms

^These reduce biodiversity.

51
Q

Describe how humans reduce the amount of land available for animals and plants.

A

HUMANS USE LAND FOR:

  • Building
  • Farming
  • Quarrying
  • Dumping waste

^this means less habitats for plants so reduces biodiversity.

52
Q

Describe how the destruction of peat bogs reduced biodiversity and releases carbon dioxide into the atmosphere.

A

Peat bogs and Peat lands contain large amounts of dead plant materials. Conditions in the peat means that decay is very slow. So peat bogs and peat lands contain a very large amount of trapped carbon.

  • These habitats are being destroyed - WHY?
  • To produce cheap garden compost.
    (another reason why this is bad is because when peat is extracted and used for compost it releases CO2 into the atmosphere which contributes to climate change)
  • Burnt to produce energy through Carbon Dioxide.

So why is destroying peat bogs bad?

  • The destruction of peat bogs is reducing the area of habitats for organisms.
  • This reduces the biodiversity.
53
Q

Why can’t farmers just use peat-free compost?

A
  • It is more expensive so if they were to use it the cost of food prices would be increased.
54
Q

What is meant by global warming?

A

the gradual increase in the average surface temperature of the Earth.

55
Q

What are the biological consequences of global warming?

x3

A

1- Loss of habitats due to the temperature of the Earth increasing.
2- Migration of species patterns may change.
3- The growth of crops may be affected.

56
Q

What is meant by peer-review?

A
  • The process by which information is checked by other scientists before it is published.
  • It helps to detect false claims to ensure research published in scientific journals are valid.
  • Reports in media are not subject to peer-review which is why there is oversimplification and bias in reporting.
57
Q

How can we reduce the loss of biodiversity?

A
  • Some governments have reduced deforestation and therefore the emission of CO2
  • Recycling resources rather than dumping waste in landfill (individuals)
    *Breeding programs for endangered species

When we do this, fewer habitats are destroyed so there is a reduction in the loss of biodiversity

58
Q

What is mean by a trophic level?

A

A trophic level is a position on a food chain.

eg

Level 1: Plants and algae make their own food and are called producers.
Level 2: Herbivores eat plants/algae and are called primary consumers.
Level 3: Carnivores that eat herbivores are called secondary consumers.
Level 4: Carnivores that eat other carnivores are called tertiary consumers. Apex predators are carnivores with no predators.

59
Q

Apex predators:

A

Carnivores with no predators.

60
Q

How do decomposers carry out decomposition?

A
  • They secrete enzymes into the environment
  • The enzymes digest the dead material
  • And the small soluble food molecules diffuse back into the decomposer.
61
Q

What is meant by a pyramid of biomass?

A

Pyramids of biomass are diagrams constructed to represent the relative amount of biomass in each level of a food chain. Trophic level 1 is at the bottom of the pyramid.

62
Q

How is biomass lost between different trophic levels?

A

Losses of biomass are due to:
* not all the ingested material is absorbed, some is egested as faeces
* some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.

63
Q

How can we calculate the efficiency of biomass transfer?

A

Effiency = gain in biomass/total biomass intake.

^^we can multiply this by 100 to turn it into a percentage.

64
Q

How to construct a pyramid of biomass:

A
65
Q

True or false, only around 1% of the light energy that falls on producers is absorbed and used for photosynthesis?

A

True.

66
Q

Look at a pyramid of biomass, as we ascend why do we observe a loss in biomass?

A

Losses of biomass are due to:
* not all the ingested material is absorbed, some is egested as faeces
* some absorbed material is lost as waste, such as carbon dioxide and water in respiration and water and urea in urine.

*Only approximately 10 % of the biomass from each trophic level is transferred to the level above it.

67
Q

What is meant by food security?

A

Food security is having enough food to feed a population.

68
Q

State some biological factors affecting food security:

x6

A

Biological factors which are threatening food security include:

  • the increasing birth rate has threatened food security in some countries
  • changing diets in developed countries means scarce food resources are transported around the world
  • new pests and pathogens that affect farming
  • conflicts that have arisen in some parts of the world which affect the availability of water or food.

Sustainable methods must be found to feed all people on Earth in order for our long-term food security to be increased.

69
Q

How do modern farming methods improve the effiency of biomass transfer?

A

The efficiency of food production can be improved by:

  • restricting energy transfer from food animals to the environment.

^^This can be done by limiting their movement and by controlling the temperature of their surroundings, typically through intensive farming.

(think of free range chickens, outside so energy for movement via glucose and heat loss so less biomass)

Some animals are fed high protein foods to increase growth.

70
Q

Advantages of factory farming:

A
  • More efficient as less biomass is wasted by animals in respiration
  • We can control the foods the animals eat and control the nutrients they need so less food is wasted
  • For chickens, eggs can be more easily harvested indoors.
71
Q

Disadvantages of factory farming:

A
  • Infectious diseases can spread more rapidly when indoors, to prevent this animals are treated with antibiotics and this may increase the risk of antibiotic resistance.
  • Keeping animals enclosed makes them more stressed so more likely to fight.
  • Ethical objections argue that animals are supposed to be raised in natural conditions and engage in normal behaviour to increase the animal’s welfare.
72
Q

Why is it important to maintain fish stocks at sustainable levels?

A

Fish stocks in the oceans are declining. It is important to maintain fish stocks at a level where breeding continues or certain species may disappear altogether in some areas.

73
Q

Describe the roles of fishing quotas and net sizing in maintaining fish stocks.

2 ways we can maintain fish stocks in the oceans:

  • Quotas
  • Net sizing

**Always say ‘‘to restore the population of fish stock’’

A
  • The fishing industry have set quotas on the number of fish that can be caught for each species - why?

^By reducing the amount of fish caught, the remaining fish can breed and bring the population levels back to normal.

  • The night size must be large enough to ensure that smaller and immature fish are not caught. This will allow for these fish to stay in the waters, survive, develop into adults and reproduce to restore the size of the fish stock.
74
Q

Describe and explain some possible biotechnical and agricultural solutions to meet the demands of the human population : x2

  • Golden rice
  • Mycroproteins
A
  • Golden rice; contains the possesses the molecules needed to make vitamin A so individuals who only have access to rice do not go blind. (Vitamin A contributes to healthy eyesight)
  • Mycoproteins:
  • These are produced by the microorganism Fusarium which is a fungus.
  • Fusarium is grown on glucose syrup in a fermentor.
  • In aerobic conditions, the fungus converts the glucose syrup into mycoproteins.
  • And this biomass is harvested and purified before being made into products which can be eaten by vegetarians. (high in protein and fibre, low in fat).
75
Q

Advantages of mycroprotein:

A
  • Suitable to vegetarians.
  • We can grow very large amounts of mycroprotein in a relatively small amount of space.

GCSE Biology (12 decks)

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