Ecology Flashcards
Ecosystem def
a community of organisms interacting with the non - living abiotic elements of their enviroments
community def
all the different population of species living in an area
species def
group of organisms with similar characteristics that can interbreed to produce fertile offspring
interdependence def
the dependence of different organisms on each other for survival e.g herbivores depend on plants
stable community
when the size of the population of all species remain relatively constant over time, the different populations are living in a healthy balance with their enviroment
abiotic def + examples
non - living component within an ecosystem e.g. light intensity, temp, wind, mineral content of soil
biotic def + examples
living components within an ecosystem e.g. predation, disease, competition, living organisms, reproduction
Plants compete for… to survive
water, sun, space and nutrients
Animals compete for … to survive
food, water, mates and territory
intraspecific competition
competition between organisms of the same species
Ecologist def
studies how living and non-living factors affect the abundance and distribution of organisms
abundance
how many organisms there are in a given area
distribution
where the organism is found within a given area
what is the grid of squares called?
a quadrat
How to get a random sample
- lay out 2 long tape measures at right angles, along two sides of the study area
- use a random number generator to get a series of random coordinates
- place a quadrat at the intersection of each pair of coordinates + record the number of species within it
Using a random generator ensures…
your data represents the true distribution and avoids bias
- We use the same size quadrat so that…
- We use 10 quadrats or more so that…
- We use random sampling so that…
- our data is valid
- our data is representative
- our data avoids bias
Estimated population size equation
EPS = total area/sample area x mean number on daisies counted
Why can you not be 100% sure the calculated population size is accurate?
some areas have more than others, its an estimate
Systematic sampling def
when the decision as to where the samples are from is not random (samples are taken at regular intervals within the habitat)
systematic sampling is used when…
there is a transition between communities along an enviromental gradient e.g. change in plant type due to changes in soil moisture)
Transect
tape measure placed on ground to help us know where to place our quadrat
How to take a systematic sample
- place the 30m tape measure from the base of a tree trunk
- place the quadrat against the transect line so one corner touches the 0m mark
- count the daisies within the quadrat
- move the quadrat 1m up the and repeat until 10m
3 kinds of adaptations in animals
- structural e.g. colour or shape
- behavioural e.g. migration
- functional e.g. reproduction, metabolism
adaptions of animals in cold climates
- must be able to keep warm
- smaller SA to volume ratio means its easier to reduce the transfer of energy and minimise cooling (many arctic mammals are relatively large)
- lots of blubber to insulate
- thick coat for insulation
Camouflage
a structural adaptation
so predators can’t be seen by pray and vice versa
surviving in dry climates
- adapted kidney so they can produce concentrated urine and need little food and water
- get water from food they eat
- during cold nights and midday, they rest in burrows
- small with a large SA to volume ratio
- large thin ears to cool down
Different levels of organisation
individual organisms, then populations, then communities, then finally to the whole ecosystem
the importance of interdependence and competition in a community
Organisms which have more of these resources tend to grow more healthily and are more likely to have offspring.
Ecosystem def
the interaction of a community of living organisms
(biotic) with the non-living (abiotic) parts of their environment.
3 things organisms might depend on other species for
food,
shelter, pollination, seed dispersal
a stable community is where…
where all the species and environmental factors are in
balance so that population sizes remain fairly constant
abiotic
non living
Abiotic factors which can affect a community are:
- light intensity
- temperature
- moisture levels
- soil pH and mineral content
- wind intensity and direction
- carbon dioxide levels for plants
- oxygen levels for aquatic animals.
Extremophiles def
organisms that live in environments that are very extreme, such as
at high temperature, pressure, or salt concentration. Bacteria living in deep sea vents are
extremophiles.
what kind of organism is responsible for creating biomass for life on Earth
photosynthetic organisms are the
producers of biomass for life on Earth.
what do producers do
synthesise molecules
order of food chain
producers -> primary consumers -> seondary consumers -> tertiary consumers
In a stable community the numbers of predators and
prey…
… rise and fall in cycles.
Field investigation equipment
- quadrat
- tape measure
- clipboard
- pen
- paper
method for:
Use random sampling to estimate the population size of a species:
- use a random number generator to obtain two numbers, which are to be used a coordinates to find a location on the two tape measures set up
- set down the quadrat at the coordinates
- count and record the number of the plant species in the quadrat
- repeat steps 1-3 to take 9 more samples
- estimate the population size using:
area samples/ total area x number of plant species counted
Method for: use continuous sampling with a transect line to investigate the effect of variation in a factor on the distribution of a plant species
- write down a hypothesis of the effect of a change in an abiotic factor (e.g. light intensity) on the distribution of the plant species
- lay down a tape measure from the base of a tree to an open area of ground/ along a location with an ecological gradient
- place the quadrat along the 0 end of the tape measure, with one corner touching the 0 mark
- count the number of plants and record it in a table as seen below
- place the quadrat at 5m intervals until you reach the end of the transect line
- repeat step 4 at 5m intervals until you reach the end of the transect line
- gather data from your class to find the mean number of plants at each point along the transect
- plot a graph of ‘number of plants’ against the ecological gradient that is observed as the distance along the transect line increases. compare your results to your hypothesis
sources of error and risk assessment for field investigation
without repetitions, the results from only one belt transect may be anomalous and not reliable
wash hands thoroughly after the experiment
many different materials cycle through…
the abiotic and biotic components of an ecosystem
the carbon cycle
- CO2 in atmosphere
- taken in by plants for photosynthesis
- plants eaten by animals
- animal died + is decomposed by microorganisms AND all living organisms release CO2 back into atmosphere (respiration) OR could be turned into fossil fuels and released into atmosphere by combustion
The water cycle
- water evaporates off surface of body of water / respiration of animals / water loss from leaf through stomata
- condensation - water rises and condenses into clouds
- precipitation - rain, sleet, snow, hail
- if it hits the ground, it sinks in and removes impurities and adds minerals (percolation)
how do microorganisms help carbon and water cycles
they feed on dead plants and animals helping them to decay so they can release cabron and water back into the atmosphere
detritivores:
1. what do they eat
2. examples
3. gas releases
4. other chemicals released?
5. increases…
- they eat dead animals and plants
- earthworms, maggots
- carbon dioxide (through respiration)
- water
- increases surface area of organic matter for decomposers
decomposers:
1. what do they do
2. examples
3. gas releases
4. other chemicals released
- they break down dead organic mattter and release enzymes and digest is externally
- microorganisms like bacteria and fungi
- carbon dioxide (through respiration)
- water and nutrients e.g. nitrates
How do these factors affect the rate of decay of biological matter?
high temp
low temp
High temp: prevents decay because the decomposer’s enzymes denature and stop working
Low: slows decay because decomposers need warmth to work in
How does lack of oxygen affect the rate of decay of biological material?
it slows most forms of decay because the detritivores and decomposers need oxygen to respire and release energy for them to work
how does lack of water affect the rate of decay of biological material?
it slows decay because decomposers need moist conditions to work otherwise they dry up and die
decomposers need…
warmth, moisture and oxygen
calculate rate of change
rate of change = change in value / change in time
How to investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change
- fill a beaker with hot water halfway (for a water bath)
- put 5cm cubed of lipase solution in a boiling tube (with syringe) and label ‘lipase’
3.put 5 drops of cresol red and 5cm cubed of milk (pipette) into a different boiling tube and label ‘milk’
4.add 7cm cubed sodium carbonate solution to the ‘milk’ tube, which should make a purple solution
5.place thermometer in milk tube + place both tubes in the water bath
6.allow time for the solutions to reach the same temp as the water bath
7.put 1cm cubed of lipase from lipase tube into milk tube and start the timer
8.record the time required for the colour to change from purple to yellow
9.repeat
source of error in decay practical
the colour change at the end point may be difficult to judge
what is used in decay practical (4 things)
milk, sodium carbonate solution, 5% lipase solution and pH indicator
what enviromental changes affect distribution of species in an ecosystem?
temp, availability of water, composition of atmospheric gases
Biodiversity
The variety of all different species of organisms on earth/ within an ecosystem
What does having great biodiversity do
Reduced the dependance of one species on another for food shelter or maintenance of the environment
Why are more resources being used /waste produced
- Rapid growth in human population
- increase in standard of living
Pollution can occur:
- in water = from sewage, fertiliser or toxic chemicals
- in air = from smoke and acidic gases
- on land = from landfill or toxic chemicals
Pollution can reduce…
Biodiversity
Humans reduce the amount of land available for other animals and plants by…
Building, quarrying, farming and dumping waste
peat bogs
- destruction reduces area of habitat = reduces biodiversity
- the decay or burning of peat releases CO2 into the atmosphere
deforestation in tropical areas has occured for…
- providing land for cattle and rice fields
- grow crops fro biofuels
levels of … are increasing contributing to…
levels of carbon dioxide and methane in the atmosphere are increasing, contributing to global warming
consequences of global warming
- loss of habitat due to extreme weather events
- decrease in biodiversity due to disrupted food chains
positive and negative human interactions in an ecosystem
negative: littering, deforestation, agriculture
Positive:
- breeding programmes for endangered species
- protection and regeneration of rare habitats,
- reintroduction of field margins and hedgerows in agricultural areas
- reduction of deforestation and CO2 emissions
trophic levels
Level 1: plants and algae = make their own food = producers
level 2: herbivores = primary consumers
level 3: carnivores = secondary consumers
level 4: tertiary consumers = eat other carnivores
what is an apex predator
carnivores that have no predators
decomposers break down dead plant and animal matter by…
secreting enzymes into the enviroment. small soluble food molecules then diffuse into the microorganism
is biomass lost or gained between each trophic level
lost, only 10% is transferred
losses of biomass are due to…
- not all ingested material is absorbed, some is egested as faeces
- some absorbed material is lost as waste, like CO2 and water in respiration and water and urea in urine
Calculate the efficiency of biomass transfers
amount from high trophic level / amount from lower trophic level
x 100
factors affecting food security
- increased birth rate
- changing diets in developed countries = scarce food resources transported around the world
- new pests and pathogens affect farming
- enviromental changes affect food production e.g. droughts
- cost of agricultural inputs
- conflicts = hard to transport food
food security
having enough to feed a population
the efficiency of food production can be improved by…
restricting energy transfers from the animals to the enviroment (limiting movement and controlling the temp of their surroundings)
some animals are fed high protein foods to increase growth
preserving fish stocks
- controlling net size
- fishing quotas
modern biotechnology techniques allows
large quantities of microorganisms to be cultured for food
the fungus… is useful for producing… when provided with…
fusarium
mycoprotein (protein rich food)
glucose syrup + oxygen
a genetically modified bacterium produces….
human insulin
GM crops could provide…
more food or food with an improved nutritional value e.g. golden rice
