Topic 7 - Ecology Flashcards
What is a habitat?
the place where an organism lives.
What is a population?
all the organisms of one species living in a habitat
What is a community?
the population of different species living in a habitat
What are Abiotic factors?
non-living factors of the environment e.g temperature
What are biotic factors?
living factors of the environment e.g food
What is an ecosystem?
the interaction of a community of living organisms (biotic) with the non-living (abiotic)parts of the environment.
What do plants compete for?
light, space, water and mineral ions (nutrients) from the soil
What do animals compete for?
space (territory), food, water and mates
why do organisms compete?
they compete with organisms from the same and different species for resources to survive and reproduce
What is interdependence?
when each species in a community depends on one another for things such as: food, shelter, pollination, and seed dispersal.
any major change in the ecosystem can have far - reaching effects
What is a stable community?
When all the species and environmental factors are in balance so that the population sizes are roughly constant.
what are the effects of one species being killed off in an ecosystem?
other animal numbers may increase and decrease. e.g.
competition increases because of less competitors, predators can have less food and substitutes decrease as a result, whatever its eating can increase
Examples of Abiotic factors are:
moisture level, light intensity, temperature, carbon dioxide level (for plants) , wind intensity and direction, oxygen level (for aquatic animals) soil pH and mineral content
What is a change in the environment?
It can be a biotic or abiotic factor, and an increase or decrease in the factor. they can affect the size of a population in a community, this means they can also effect a dependent species.
An example of an abiotic change in the environment scenario is:
a decrease in temperature, light intensity or carbon dioxide could decrease photosynthesis, this can affect plant growth and population size, so can a decrease in mineral content in the soil, which can affect plant growth
Examples of Biotic factors are:
New predators arriving,
new pathogens,
Availability of food,
competition - one species may out-compete another so that numbers are too low to breed
An example of a biotic change in the environment scenario is:
A new predator can cause a decrease in population.if two different species compete for the same food one may out compete the other causing their population to decrease
What is structural adaptation?
the features of an organisms body structure - shape or colour.e.g. white fur on arctic foxes for camouflage against predators and prey.thick layer of blubber on whales and low surface area to volume ratio to stay warm.thin layer of fat and large surface are to volume ratio on camels to cool down
What is behavioural adaptation?
The way organisms behave, e.g. migrating to warm climates in winter to avoid living in cold conditions
What is functional adaptation?
The chemical reactions that happen inside the body.e.g. dessert animals produce little sweat and urine -which is concentrated. brown bears hibernate over winter and lower metabolism because there isn’t much food
What are extremophiles?
they’re adapted to live in extreme conditions e.g. high temperatures, high salt content, or at high pressure
What do food chains always start with?
a producer
What are producers?
green plants or algae, they make glucose by photosynthesis. some of the glucose is made in to other biological molecules, which is the plants biomass
what is biomass?
the mass of living material
how do food chains work?
the biomass of a of a plant can be thought of as energy stored in a plant. when an organism eats the plant the energy is transferred to the organism.
What is the order of consumers?
producers are eaten by primary consumers. primary consumers are eaten by secondary consumers. secondary consumers are eaten by tertiary consumers.
how do stable communities work?
population is limited to available food. if prey numbers go up then predators will increase too. as predators increase prey decrease then predators decrease, so prey increase again and so on. They are out of phase because it takes a while for 1 population to respond to changes in the other.
What is the distribution of an organism?
where it is found, e.g. a part of the habitat. it is affected by environmental factors, it might be more common in one area than another.
The ways to study the distribution of an animal are:
using quadrats to measure how common an organism is in 2 sample areas, place the quadrat along a transect to study the changes across the area
what is a quadrat?
a quadrat is a square frame used to enclose an area. it is 1m²
How is a quadrat used?
- place the quadrat on the ground at a random point in the first sample area
- count all the organisms within the quadrat
- repeat steps 1 and 2 as many times you can
4.work out the mean number of organisms per quadrat within the first sample area
<u>total number of organisms</u>
number of quadrats - repeat steps 1 to 4 in the second area
- compare the 2 means
what is the population size sometimes called?
its abundance
how can 1 area be used to work out the population size of an organism?
work out the mean population size of an organism for 1m², then times it by the area you’re observing e.g. a field
how are transects used?
- mark out a line using a tape measure
- collect data along the line
- this can be done by counting all the organisms you want to observe that touch the line
- or collect data using quadrats, by placing them next to each other along the line or at intervals.
how can you estimate the percentage cover of a quadrat?
- count the number of squares covered by the organism
2. divide it by the number of squares in a quadrat
how many squares are there in a quadrat?
100
what environmental changes could affect the distribution of an organism?
Availability of water, Temperature, Atmospheric gases
how can availability of water affect distribution?
with wet and dry seasons, when there is less water available there will be less organisms because they can’t survive without water e.g. wildebeest follow the rainfall around Africa
how can atmospheric gases affect distribution?
some species are changing because of the amount of air pollution in their area e.g. some lichen can’t grow in areas with sulphur dioxide.
how can temperature affect distribution?
bird species are moving because of temperature (migration) e.g. European bee eaters were a Mediterranean species but re now seen in Germany
What factors can cause environmental changes?
seasonal factors, geographic factors or human factors
describe the water cycle
- energy from the sun makes water evaporate in to water vapour
- water vapour is carried upwards then it cools and condenses in to clouds
- the water then precipitates and provides fresh water for plants and animals
- it drains in to the sea and the process repeats
what is it called when water evaporates from plants?
transpiration
examples of materials from the world around an organism being part of it is:
plants turn elements such as carbon, oxygen, hydrogen and nitrogen from the soil and air in to complex compounds (carbohydrates, proteins and fats) that make up living organisms, they are passed down the food chain
how are materials that make up organisms recycled?
they are returned to the environment as waste products, or as decay and then they are used again.
why do materials decay?
because they are broken down by microorganisms. this happens faster in warm, moist, aerobic conditions because then the microorganism’s are more active. decay puts stuff plants need to grow back in to the soil
how are materials used in a stable community?
because they are taken out of the soil and used by plants etc and then are replaced by the materials that go back in. it is a constant cycle
why is biodiversity important?
makes ecosystems stable, because different species depend on each other for food and shelter, and maintain physical environment.they help humans survive
what human actions are reducing biodiversity?
waste production, deforestation and global warming
why has human population raised?
the population of the world is rising very fast mostly due to medicine and farming methods, which have reduced the number of deaths.
how has our population effected the environment?
there is so many of us and we take resources from the environment to survive. people are demanding a higher standard of living, so we are using more resources to make and power stuff. raw materials are being used up quicker than they can be replaced, so we’re going to run out
how do we produce more waste?
as we make more things we produce more waste, including waste chemicals . if this waste isn’t handled more harmful pollution will be caused.
what does pollution affect?
water, land and air, and kills plants and animals, reducing biodiversity.
how does waste affect water?
sewage and toxic chemicals from industries pollute lakes, rivers and oceans, affecting the plants and animals that rely on them to survive, and the chemicals on land can be washed in to the water
how does waste affect land?
toxic chemicals are used for farming (pesticides and herbicides) we also bury nuclear waste underground and dump household waste in landfill sites
how does waste affect air?
smoke and acid gases released into the atmosphere can pollute the air e.g. sulphur dioxide can cause acid rain
what are the main greenhouse gases?
CO² and methane
what do humans use land for?
building, quarrying, farming and dumping waste, this means less land available for other organisms.
how does the way we use land have bad affects on the environment?
sometimes it requires deforestation, or the destruction of habitats like peat bogs and other areas of peat.
what are the reasons for deforestation?
to clear land for farming, to provide more food
to grow crops from which bio fuels based on ethanol can be produced.
what problems can deforestation cause?
less carbon dioxide taken in, more carbon dioxide in the atmosphere, less biodiversity
explain how deforestation leads to less carbon dioxide taken in
cutting down loads of trees means that less carbon dioxide takes place which means less carbon dioxide is taken in.
trees keep some CO² stored in their wood, removing trees means less it stored away
explain how deforestation leads to more carbon dioxide in the atmosphere
carbon dioxide is produced when trees are burnt to clear the land. the CO² stored in the wood is also released.
microorganisms feed on dead wood and release carbon dioxide through respiration.
explain how deforestation leads to less biodiversity
the more species the greater the biodiversity.
habitats like forests can contain a huge number of plant and animal species, when they are destroyed there is less biodiversity and species may become extinct.
what are peat bogs?
bogs are areas of land that are acidic and water logged. plants that live in bogs don’t fully decay when they die because there’s not enough oxygen. the partly rotted plants build up to form peat.
how does the destruction of peat bogs add more CO² to the atmosphere?
the carbon in the plants is stored in the peat. when peat is drained it comes in contact with the air , microorganisms begin to decompose it, they respire, take in oxygen and release CO².
CO² is released when it is burnt for fuel.
destroying bogs also destroys habitats and reduces biodiversity
what are peat bogs used for?
peat bogs are often drained so the area can be used as farmland, or it is cut up and used for fuel, or sold to gardeners as compost. peat is being used faster than it forms.
how is biodiversity being maintained?
breeding programmes, protecting and regenerating rare habitats, reintroduction of habitats, regulations to reduce deforestation, and recycling
how are breeding programmes maintaining biodiversity?
to prevent endangered animals from going extinct. they are bred in captivity, to make sure the species survives if it dies out in the wild. some are released to boost or re-establish a population.
how is protecting and regenerating habitats maintaining biodiversity?
mangroves, heath lands and coral reefs are protected to protect the species that live there, preserving ecosystems and biodiversity
how is the reintroduction of habitats maintaining biodiversity?
hedgerows and field margin’s are being reintroduced around fields on farms because it is where wild flowers and grasses are grown and the habitats of many organisms
how are anti-deforestation programmes maintaining biodiversity?
they are reducing the level of deforestation and the CO² released in to the atmosphere by businesses. this reduces global warming
