B7:Ecology Flashcards Preview

GCSE AQA BIOLOGY (PAPER 2) > B7:Ecology > Flashcards

Flashcards in B7:Ecology Deck (113):


The place where an organism lives.



All the organisms of one species living in a habitat.



The populations of different species living in a habitat.


Abiotic factors

Non-living factors of the environment.


Biotic factors

Living factors of the environment.



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


Organisms compete for resources to...

Survive and reproduce.


Who do organisms compete with?

Other species and members of their own species for the SAME resources.


Give 4 examples of things Plants compete for:

- light
- space
- water
- mineral ions from the soil.


Give 4 examples of things animals compete for:

- space
- food
- water
- mates.


What is Interdependence?

In a community, each species depends on other species for things such as pollination, food, seed dispersal and shelter.


The interdependence of all living things in an ecosystem means...

That any major change in the ecosystem can have far reaching effects.


What are stable communities?

Where all the species and environmental factors are in balance so that the population sizes are roughly constant.


Give 2 examples of stable communities:

- tropical rainforests
- ancient oak woodlands.


List 7 Abiotic factors:

1) Moisture level
2) Light Intensity.
3) Temperature.
4) Carbon dioxide level.
5) Wind Intensity and direction.
6) Oxygen level.
7) Soil pH and mineral content.


A change in the environment could be...

An increase or decrease in an abiotic factor e.g increase in temperature.


How can Abiotic factors affect a community?

They can affect the size of populations in a community - including the population sizes of other organisms that depend on them.


List 4 examples of Abiotic Factors:

1) New predators arriving.
2) Competition.
3) New Pathogens.
4) Availability of food.


A change in the environment could be...
(Biotic factor)

The introduction of a new biotic factor e.g. new predator.


How can Biotic factors affect a community?

They can affect the size of populations in a community which has a knock on effect because of interdependence.


Organisms are...

Adapted to live in different environmental conditions.


Give 3 ways Organism’s can be adapted:

- Structural (body)
- Behavioural
- Functional (processes inside body)


Give an example of a Camel’s structural adaptation:

They have a thin layer of fat and a large surface area to volume ratio to help them lose heat.


Give an example of a Behavioural Adaptation:

Many species migrate to warmer climates during the winter to avoid the problems of living in cold conditions.


What are Functional adaptations?

Things that go on inside an organism’s body that can be related to processes like Respiration

and metabolism.


Give an example of a Functional adaption of a bear:

Brown bears hibernate over winter. = lowers metabolism which conserves energy so they don’t have to hunt when there’s not much food about.


Give 3 examples of adaptations that Microorganisms can have:

- living in high temperatures.
- living in places with high salt concentration.
- living in high pressure.


What is it called when microorganism can live in extreme conditions?

They are known as extremophiles.


Food chains show...

What’s eaten by what in an ecosystem.


Food chains always start with...
How do they make their food?

A producer.
They make their own food using energy from the sun.


Producers are usually...

Green plants or algae.


What happens when a green plant makes glucose?

Some of it is used to make other biological molecules in the plant.


Biological molecules are...

The plant’s biomass - the mass of living material.


Biomass can be thought as...

Energy stored in a plant.


When is energy transferred?

Energy is transferred through living organisms in an ecosystem when organisms eat other organisms.


Producers are eaten by...

Primary consumers.


Primary consumers are eaten by...

Secondary consumers.


Secondary consumers are eaten by...

Tertiary consumers.


What are predators?

Consumers that hunt and kill other animals.


What do predators eat?

Their ‘prey.’


The population of any species is usually limited by...

The amount of food available.


If the population of prey increases, what would happen?

So will the population of the predators - as they have more food.


What happens if the population of predators increase?

The number of prey will decrease - there are more predators to eat them.


Predator prey cycles are always...

Out of phase with each-other - because it takes a while for one population to respond to changes in the other population.


The water cycle means...

Water is constantly recycled.


Give the first step of the water cycle: (2)

1) Energy from the sun makes water evaporate turning into water vapour

2) This also happens from plants - known as transpiration.


What happens to the warm water vapour?

It is carried upwards and when it gets higher up it cools and condenses to form clouds.


Give the second step of the water cycle: (2)

1) Water falls from clouds as precipitation onto land - provides fresh water.

2) Some of it is absorbed by the soil and it is taken up by plant roots - provides water for photosynthesis. Some of the water also taken by plants to become part of the plants tissues and is passed along to animals in food chains.


Like plants, animals need water for...

The chemical reactions that happen in their bodies.


Give the final step to the water cycle:

1) Animals return water to the soil and atmosphere through excretion.

2) Water that doesn’t get absorbed the soil will runoff into streams and rivers.


After the full water cycle has happened....

The water drains back into the sea, before it evaporates all over again.


Living things are made of...

Materials that they take from the world around them.


What happens to the materials stored in living things?

They are returned to the environment in waste products or when the organisms die and decay.


Why do materials decay?

Because they’re broken down (digested) by microorganisms.


Where does material decay happen fastest?

In warm, moist, aerobic conditions because microorganisms are more active there.


What does decay do?

It puts the stuff that plants need to grow back into the soil.


What happens to the materials taken out in a stable community?

The materials are balanced by those that are put back in - there’s a constant cycle happening.


Give the first step to the Carbon Cycle: (2)

1) CO2 is removed from the atmosphere by green plants & algae during photosynthesises.

2) When they respire, some Carbon is returned to the atmosphere as carbon dioxide.


Give the second step to the Carbon Cycle:

1) When the plants/algae are eaten by animals - some Carbon becomes part of the fats and proteins in their bodies.


The Carbon moves through...

The food chain.


When the animals respire...

Some Carbon is returned to the atmosphere as carbon dioxide.


What happens when plants, algae and animals die?

Other animals (detritus feeders) and microorganisms feed on their remains - and when these respire the CO2 is returned.


Animals also produce waste...

That is broken down by detritus feeders and microorganisms.


What else releases CO2?

Combustion of wood and fossil fuels.


So Carbon is constantly...

Recycled - from the air, through food chains and then back out into the air again.


What is Biodiversity?

The variety of different species of organisms on Earth, or within an ecosystem.


Why is high biodiversity important?

It makes sure that ecosystems are stable because of interdependence.


Different species can also help to...

Maintain the right physical environment for each other.


For the human species to survive, what’s important?

It’s important that a good level of biodiversity is maintained.


What is reducing biodiversity? (3)

- waste production.
- deforestation.
- global warming.


The population of the world is...

Currently rising very quickly.


Why is the population of the world increasing?

Due to modern farming and medicine methods - they have reduced the number of people dying from disease and hunger.


An increasing population - How is this bad for the environment?

We have a bigger effect on the environment.


Give 3 examples of way our increasing population is harming the environment:

1) Puts pressure on the environment as we take resources.

2) People are demanding a higher standard of living so we use more raw materials and energy through the manufacturing process.

3) Raw materials are being used up quicker than they’re being replaced - we will run out one day.


As we make more and more things, we produce more and more...

Waste - including waste CHEMICALS.


What happens if our waste is not properly handled?

More harmful pollution will be caused.


Give an example of Air Pollution:

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


Give three examples of Land Pollution:

We use toxic chemicals for farming (herbicides etc) and

we bury nuclear waste underground

& we dump a lot of household waste in landfill sites.


Give two examples of Water Pollution:

-Swear and toxic chemicals from industry can pollute lakes, rivers and oceans affecting plants and animals that rely on them.

-Chemicals on land can be washed into water too.


Pollution affects...

Water, land and air and kills plants and animals - reducing biodiversity.


The temperature of the Earth is a balance between...

The energy it gets from the sun and the energy it radiates back out into space.


Gases in the atmosphere naturally act...

Like an insulating layer.


What do Gases in the atmosphere do?

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.


What are the two main greenhouse gases we are worried about?

Carbon dioxide and Methane because their levels are rising quite sharply.


What is Global Warming?

The Earth is gradually heating up because of the increasing levels of greenhouse gases.


Global warming is a type of...

Climate Change and it causes other types of climate change e.g. changing rainfall pattern.


Give 3 examples of issues Global Warming can cause:

1) Higher temp = seawater expands and ice melts causing sea levels to rise. Could lead to flooding and loss of habitat.

2) Reduces biodiversity if some species are unable to survive the climate change.

3) Change In migration patterns e.g. birds may migrate further North.


Give 4 examples of things Humans use land for:

- building.
- quarrying.
- farming.
- dumping waste.


As humans use land for lots of things, this means...

There’s less land for other organisms.


Sometimes, the way we use land can have...

A bad effect on the environment.


What is Deforestation?

The cutting down of forests.


When does Deforestation cause big problems?

When it’s done on a large scale e.g. cutting down rainforests in tropical areas.


Give 2 reasons why Deforestation is done:

- to clear land for farming to provide more food.

- to grow crops from which biofuels based on ethanol can be produced.


How does Deforestation affect carbon dioxide?

Cutting down the trees means the amount of CO2 removed during photosynthesis is reduced. Less carbon is locked up in the trees.


How does Deforestation cause more carbon dioxide?

CO2 is released when trees are burnt to clear land. Microorganism feeding on bits of dead wood release it as a waste production of respiration.


How does Deforestation cause less Biodiversity?

Habitats like forests can contain a huge number of different plans and animals so when they are destroyed = there is a danger of species becoming extinct.


What are bogs?

Areas of land that are acidic and waterlogged.


What happens to plants that live in bogs? Why?

They don’t fully decay when they die because there’s not enough oxygen. The partly rotted plants gradually build up to form peat.


So where is the carbon in plants stored?

In the peat instead of into the atmosphere.


Why are peat bogs drained? (2)

So that the area can be used as farmland or the peat is cut and dried to use as fuel.

Also sold to gardeners as compost.


What happens when peat is drained? How does this contribute to Global Warming?

It comes into more contact with air and some microorganisms start to decompose it.

When they respire, they use oxygen and release CO2 contributing to global warming.


Carbon dioxide is also released when...

The peat is burned as fuel.


Destroying the bogs also destroys...

Some of the habitats of animals, plants and microorganisms = reducing biodiversity.


Give 3 examples of things people are doing to maintain Ecosystems and Biodiversity:

- Breeding programmes to prevent endangered species being extinct.

- People are encouraged to recycle/reduce the amount of waste that gets dumped in landfill.

- Some Governments have introduced regulations and programmes to reduce the level of Deforestation by businesses.


Give 3 examples of things that are conflicting pressures on maintaining Biodiversity:

- protecting biodiversity costs money e.g. to keep a watch on it if Rules and regulations are being followed.

- land is in such high demand that previously untouched land with high biodiversity HAS to be used.

- sometimes certain organisms are seen as pests by farmers and are killed to protect crops and livestock so that we have more food.


How can increasing biodiversity affect the local economy?

E.G. reducing the amount of Deforestation is great but for people who were previously employed in the tree felling industry could be left unemployed.


What can you use transacts for? What are they?

They are lines that help you to find out how organisms like plants are distributed across an area.


Give the 4 steps to using Transects to study the distribution of Organisms:

1) Mark out a line in the area you want to study using a tape measure.

2) Then collect data along the line by counting all the organisms you’re interested in that touch the line.

3) Or you can collect the data by using quadrants - these can be placed next to each other along line.


What is the distribution of an organism?

Where an organism is found.


Where an organism is found is affected by...

Environmental factors e.g. daisies are more common in the open than under trees because there’s more light.


What is a Quadrat?

A square frame enclosing a known area e.g. 1m squared.


Give the steps to working out how common an organism is in two sample areas: (5)

1) place a 1m squared quadrat on the ground at a random point using a random number generator.

2) Count all the organisms within the quadrat.

3) Repeat steps 1 and 2 as many times as you can.

4) Work out the mean number of organisms per quadrat within the first sample area.

5) Repeat all the steps for a second sample area and compare the two means


Give the formula to find the mean of organisms in a quadrat:

Total number of organisms
Number of Quadrats