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