Flashcards in Topic 7 - Ecology Deck (181):
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:
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,
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?
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?
1. place the quadrat on the ground at a random point in the first sample area
2. count all the organisms within the quadrat
3. 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
total number of organisms
number of quadrats
5. repeat steps 1 to 4 in the second area
6. compare the 2 means
what is the population size sometimes called?
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?
1. mark out a line using a tape measure
2. collect data along the line
3. this can be done by counting all the organisms you want to observe that touch the line
4. 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?
1. 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?
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
1. energy from the sun makes water evaporate in to water vapour
2. water vapour is carried upwards then it cools and condenses in to clouds
3. the water then precipitates and provides fresh water for plants and animals
4. it drains in to the sea and the process repeats
what is it called when water evaporates from plants?
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
how is recycling maintaining biodiversity?
it reduces the amount of waste that gets dumped in landfill sites. this reduces the amount of land taken over by landfill, leaving ecosystems in place.
what are the problems with maintaining biodiversity?
it costs money, it leaves people unemployed, it could mean less food production, development is important
how is cost a problem with biodiversity?
it costs money to pay farmers to reintroduce hedgerows etc, cost money to make sure people are following programmes
how is unemployment a problem with biodiversity?
people who cut down trees lose jobs, people can move away to find jobs - affects economy
how is less food a problem with biodiversity?
pests that eat our crops are being protected, there's less food
how is development a problem with biodiversity?
some places desperately need to be developed, for example places with high diversity for new houses
what is compost?
decomposed organic matter that is used as a natural fertiliser for crops and garden plants.
what factors affect rate of decay?
number of decay organisms
what organisms cause decay?
bacteria and fungi as well as detritus feeders are responsible for decay. they work best in the right conditions.
how does temperature effect the rate of decay?
warmer temperature means faster decomposition because it increases the rate the enzymes decomposing work at.
too hot, then the enzymes are destroyed and organisms die.
cold temp slows decomposition too
how does oxygen availability affect the rate of decay?
most organisms need oxygen to respire, which they need to do to survive. microorganisms that perform anaerobic decay don't need oxygen
how does water availability affect the rate of decay?
its faster in moist environments because microorganisms involved in decay need water to carry out biological processes
how does the number of decay organisms affect the rate of decay?
the more microorganisms and detritus feeders there are, the faster decomposition happens
what gas is bio gas mainly made up of?
methane, which can be burned as fuel
how do microorganisms produce bio gas?
they decay plant and animal waste anaerobically (without oxygen), this type of decay produces methane gas
how is bio gas produced on a large scale?
sludge waste from places like sewage works or sewage factories is used to make bio gas on a large scale
how must biogas be made and stored?
biogas generators need to be kept at a constant temperature to keep the microorganisms respiring. biogas can't be stored as a liquid (it needs to high a pressure), so it has to be used straight away.
what can biogas be used for?
heating, cooking, lighting, or to power a turbine to generate electricity
what are the 2 types of biogas generator?
batch generators and continuous generators
what are batch generators?
make biogas in small batches. manually loaded with waste, which is left to digest, by-products are cleared away at the end of each session
what are continuous generators?
make biogas all the time. waste continuously fed in, biogas produced at a steady rate. more suited for large-scale biogas projects.
what must all biogas generators have?
1. an inlet for waste material to be put in
2. an outlet for digested material to be removed through
3. an outlet so that the biogas can be piped to where its needed
what does the decay practical investigate?
how temperature effects decay. it uses indicator which is pink with a pH of around 10 but colourless with a pH below 8.3
how to investigate decay? (short)
observing action of an enzyme to milk made alkaline. when the enzyme breaks down the milk, pH decreases
what is needed for a decay practical?
5 cm^3^ of lipase solution in a test tube
5 cm^3^ of milk in test tube
5 drops of phenolphthalein indicator
7 cm^3^ of sodium carbonate solution
Whats the method of the decay practical?
add the indicator and sodium carbonate to the milk
this will make the solution alkaline so it will go pink
put pink milk and lipase in a heated water bath
after the test tubes have reached the right temperature add 1 cm^3^ to the milk and start a stopwatch
stir the solution until milk decomposes and loses colour
record time taken
repeat the experiment several times at different temperatures and calculate rate of decay
what is the formula to find rate of decay?
what are the units for rate of decay?
what should be the results of the decay investigation?
the hotter the solution the faster the rate of decay
what is the temperature of the earth made up of?
its a balance between the energy it get from the sun and the energy it radiates back out to space
how do gases in the atmosphere act as a natural insulating layer?
they absorb most of the energy that would normally be radiated out into space, and re-radiate it in all directions, including back to earth. this increases the earths temperature
why is a layer of gas around the earth necessary?
if it was nothing there then at night there would be nothing keeping the energy in so we would freeze at night
what are the gases called that insulate the planet?
why is the earth heating up?
because of increasing levels of greenhouse gases - this is global warming. this is a type of climate change and causes other types of climate change
what are the consequences of global warming?
change in distribution of organisms,
changes in migration patterns,
how is flooding a consequence of global warming?
high temperatures make seawater expand and ice melt ,causing sea levels to rise. if this gets worse then humans and animals in low-lying places will be in trouble as flooding will mean loss of habitats
how might changes in the distribution of wild organisms be a consequence of global warming?
as temperature increases the amount of rainfall changes in different areas. species living in hot conditions may become more widely distributed, but species living in cold conditions may be less widely distributed as their conditions are less common
how might changes in migration patterns be consequences of global warming?
for example some birds may migrate north as more northern areas are getting warmer
how is reduced biodiversity a consequence of global warming?
biodiversity could be reduced if some species are unable to survive a change in the climate, so become extinct
what are trophic levels?
different stages of a food chain. they consist of 1 or more organisms that perform a specific role in the food chain
what are the trophic levels called?
they are named after their location in the food chain using number. the 1st is called trophic level 1, the organism next in the food chain are on trophic level 2 and the levels continue like that
what does trophic level 1 contain?
what is a producer?
these are the organisms at the starting point of a food chain. they're called producers because they make their own food by photosynthesis using energy from the sun.
what does trophic level 2 contain?
what is a primary consumer?
herbivores that eat plants and algae. they don't eat anything else
what does trophic level 3 contain?
what is a secondary consumer?
carnivores that eat the primary consumers. carnivores are meat eaters
what does trophic level 4 contain?
what are tertiary consumers?
carnivores that eat other carnivores (secondary consumers). carnivores that don't have predators are at the top of the food chain, so they have the highest trophic level. they're know as apex predators
how do decomposers play an important role in ecosystems?
they decompose any dead plant or animal material left in an environment. in doing so they release nutrients which producers need to grow.
how do decompose dead organisms
by secreting enzymes that break down the dead stuff into smaller soluble food molecules, these then diffuse into the microorganisms
what does secrete mean?
what do organisms get less of when they move up a trophic level in the food chain?
less energy and less biomass every time you move up a stage. there are usually fewer organisms every time you move up a stage as well.
e.g. 100 dandelions -> 10 rabbits -> 1 fox
how to represent the proportions in a food chain?
sometimes there are more organisms when you move up a stage, rather then less. so the best way to look at a food chain is to think of biomass not number of organisms. this information can then be made into a pyramid of biomass to represent the food chain.
what does each bar on a pyramid of biomass show?
the relative mass of living material at a trophic level. basically how much all the organisms at each level would weigh if you put them all together.
example of a pyramid of biomass?
in one with dandelions, rabbits, fox's and fleas, the dandelions would have the biggest biomass then rabbits, then fox's then fleas, even though their were more fleas eating then fox's
how must the biomass be drawn?
the biomass at each stage should be drawn to scale. biomass is decreasing as you go up the levels so the pyramid levels get smaller as you go up
what to remember about drawing pyramids of biomass?
if you get actual numbers you can use them to draw bars to the right scale. the order of organisms must follow the order of the food chain. each bar must be labelled
what is the source of energy for nearly all life on earth?
how do producers make energy?
they use energy transferred by light from the sun to make glucose during photosynthesis. only about 1 % of the energy they get is transferred for photosynthesis.
how do plants make biomass?
some of the glucose plants make is used to make biological molecules. these molecules make up a plants biomass(mass of living material). Biomass stores energy
how much biomass is passed on to each stage of the food chain?
biomass is passed through a food chain in ecosystems when 1 organism eats another. not much biomass is passed from 1 stage to another, only about 10% of the biomass is passed on to the next level.
how might biomass be lost?
not all of the organism is eaten
they don't absorb all the energy in the food
some of the biomass is made into other substances
how is biomass lost if not all of the organism is eaten?
organisms don't always eat every part of the organism they are consuming. e.g. some material that makes up plants and animals is inedible, so not all of the biomass can be passed on to the next stage.
how can biomass be lost by not using all the energy in the food?
organisms don't absorb all the stuff in the food they ingest. the stuff that they don't absorb is egested as faeces, so some biomass is lost.
what does egested mean?
how is some of the biomass taken in lost by converting into other waste substances?
organisms use lots of glucose from biomass to respire to provide energy, this produces waste like CO2 and water as by-products. Urea is another waste substance released in urine with water when the proteins in biomass are broken down
what is the mass provided for making a pyramid of biomass?
it is the amount of biomass available to the next level. the amount of 1 type of organism is the amount available to the next organism in the food chain
how can you work out how much biomass has been lost at each level?
by taking away the biomass that is available at that level from the biomass available at the previous level
how to calculate the efficiency of biomass transfer between trophic levels?
biomass transferred to next level
efficiency = biomass available at previous level X100
what is food security?
having enough food to feed a population.
what can threaten food security?
the growing population
demand for food
negative affects on farming
costs of farming
how can rising birth rate affect food security?
with birth rate of many developing countries rising quickly, population keeps increasing. so there's more people to eat the food
how can demand for food threaten food security?
as diets in developed countries change, the demand for certain foods to be imported from developing countries increases. scarce foods become more scarce
how can the negative affects on farming threaten food security?
farming can be affected by pests, pathogens or changes in the environmental conditions. this can lead to a loss of crops and livestock, which can lead to widespread famine
how does the cost of farming threaten food security?
the high input costs of farming can make it too expensive for people in some countries to start or maintain food production, meaning there isn't enough food being produced in these countries
how does conflict threaten food security?
in some parts of the world conflict effects the availability of food and water
what are examples of the high input costs of farming?
the price of seeds, machinery and livestock
why are fish stocks declining?
fish stocks are declining in the oceans because we're fishing so much
what does our over fishing mean?
there's less fish to eat, the oceans food chains are affected, some species of fish may disappear completely in some areas e.g. cod at risk of disappearing from north west Atlantic
how can we tackle the problem of over fishing?
by maintaining fish stocks at a level where the fish continue to breed , this is sustainable food production.
in what ways can fish stocks be conserved?
how can fishing quotas maintain fish stocks?
these are limits on the number and size of fish that can be caught in certain areas. this prevents certain species from being over fished.
how can net size maintain fish stocks?
there are different limits on the size of the mesh of fish nets, depending on whats being fished, this is to reduce unwanted and discarded fish.
examples of unwanted fish that net size could save?
shrimp being caught with cod, bigger mesh means the shrimp can escape.
larger gaps in the mesh also means young fish can escape and reach breeding age
how do farmers make livestock use less energy?
limit the movement of livestock and keep them in a temperature controlled environment which reduces the transfer of energy from livestock to the environment.
how do farmers make farming livestock more efficient?
by making them use less energy, this makes it more efficient as they lose less energy moving and controlling body temperature. more energy is available for growth, more food can be produced from the same input of resources.
examples of livestock being farmed more efficiently:
calves and chickens can be factory farmed, raising them in small pens
fish factory farmed in cages with restricted movement
animals fed high-protein food to increase growth
how are some factory farming methods controversial?
animals kept close together, disease can spread easily. there are ethical objections, like unnatural and uncomfortable conditions are cruel
where living things and biological processes are used and manipulated to produce a useful product.
how can large amounts of microorganisms be used as a food source?
using modern biotechnology techniques, large amounts of microorganisms can be cultured industrially under controlled conditions in large vats
what is Mycoprotein used for?
its used to make high-protein meat substitutes for vegetarian meals
what is Mycoprotein made of?
its made from the fungus Fusarium, which is grown in aerobic conditions on glucose syrup, which it uses as food
how can fungus make Mycoprotein?
the fungal biomass is harvested and purified to make Mycoprotein
what is genetic engineering?
transferring a useful gene from 1 organism to another, bacteria can genetically engineered to make human insulin
what is the first step to making human insulin from a bacteria?
remove a plasmid (loop of DNA) from a bacterium
what is the 2nd step to making human insulin from a bacteria?
cut insulin gene from human chromosome using restriction enzyme. these enzymes recognise specific sequences of DNA and cut the DNA at these points.
what is the result of cutting DNA?
the cut leaves 1 of the DNA strands with unpaired bases (this is called a sticky end)
what is the 3rd step to making human insulin from a bacteria?
the plasmid is cut open using the restriction enzyme, leaving the sticky ends
what is the 4th step to making human insulin from a bacteria?
the plasmid and the human insulin are mixed together
what is the 5th step to making human insulin from a bacteria?
the enzyme, ligase is added. this joins the sticky ends to produce recombinant DNA
what is recombinant DNA?
2 different bits of DNA stuck together
what is the 6th step to making human insulin from a bacteria?
the recombinant DNA is inserted into a bacterium
what is the 7th step to making human insulin from a bacteria?
the modified bacterium is grown in a vat under controlled conditions. you end up with millions of insulin producing bacteria.
what can be done with the bacteria that produce insulin?
the insulin can be harvested and purified to treat people with diabetes
how can help people in developing countries who don't have enough food or a varied diet?
how can biotechnology help the lack of food in developing countries?
genetically modified crops can be produced that are pest resistant or to grow better in drought conditions, which can improve crop yield.
or modified to provide more nutritional value
whats an example of a crop modification to provide more nutritional value?
golden rice, has been genetically engineered to produce a chemical thats converted to vitamin A in the body