Section 7 Flashcards
(35 cards)
SAMPLING METHODS
two types of Quadrat
what size
what number
- point quadrat = use on grassland, doesnt squash species
- frame quadrat
- with largwr species = larger quadrats
- uneven distribution = large number of smaller quadrats
- the more quadrats = more reliable results
- the greater number of species = greater number of quadrats
- keep sampling till running mean is consistant
RANDOM SAMPLING
- comparing two different areas
- avoids bias, more reliable
- tape measure at right angles 10mby10m
- get random coordingates by using random number generators
- placed quadrat in a standardised matter eg: left corner of the coordinate ( 0.25m^2) ( x5 to 1m then to area)
- record abundance = frequency and % cover
- repeat 20x till running mean is consistant
RANDOM SAMPLING
limitations
- quadrats only covering a small part of the total area
- unreprisentative
- snapshot effect = only data one time
- light and wind change throught the day
- cannot be used to measure moving organisms
SYSTEMATIC SAMPLING
- used when looking at the distribution and abundance
- where there is a gradual change in communities
- belt transet ( interuppted ( longer distances) or continuous )
- frame quadrat layed alongside the line
RANDOM SAMPLING
limitations
- only covers small total area
- snapshot effect = one day
- light and wind change throught the day
- cant measure moving organisms
SAMPLING
abundance
frequency = quick idea of species, doesnt tell about distribution or density
% cover = data collected quickly , doesnt need to count individuals, not usedful when species overlap
COMMUNITY INERACTIONS
( 3 )
- inter specific competition ( -/-)
- predatation ( bad for prey )
- herbivory ( not good for plants )
COMPETITION
inter and intra
what they compete for biotic/abiotic
inter = different species
intra = same species
biotic =
- food, mates, pollinators
abiotic =
- minerals, water, light, space
COMPETITION
competitive exclusion
- 2 species competing for same resources cannot co exist due to occupying the same neiche
PREDATOR PREY RELATIONSHIPS
always more prey = more energy
- less passed to next level ( predator)
eg: used for respiration, not all eaten, excretion
- predator number decrease due to low number of prey ( starve )
- low number of predators increase number of prey ( less eaten )
- higher number of prey = more food for predators decreasing prey
KEY WORDS
population
adaptation
ecology
carying capacity
- all organisms of one species within an ecosystem
- characteristics developed by different species, allowing them to better exploit their neiche
- study of interactions between organisms and environment
- maximum stable population size of a species that an environment can sustainibly support
KEY WORDS
community
ecosystem
neiche
habitat
- all the popuations of all the differebt species in the same ecosystem of habitat
- made up of a community and their interactions with the environment
- the role organisms occupies within its environment
- place which is the typical environment for an organism
POPULATION GRAPHS
three stages names
- slow growth
- rapid growth
- stable state, no growth
POPULATION GRAPHS
slow growth
rapid growth
stable state
descriptions
- small number of individuals reproduce slowly
- rapid growth where the ever increasing number of individuals continue to reproduce
- decline may be due to food supply or increased predation
POPULATION GRAPHS
why use log
- have a wide range in the data
POPULATION GRAPHS
limiting factors
o2, food, disease, predators , space
ECOLOGICAL SUCESSION
definiton
- progressive chnage in the composition and diversity of the species in a community in one place over a period of time
ECOLOGICAL SUCESSION
whats primary sucession
start in new habitat with no soil and no previous community
ECOLOGICAL SUCESSION
whats a poineer species
- can colonise a hostile env
- overtime alter abiotic conditions
- naking it less hostile to allow more species
eg: lichen
usedful features:
- cope with hostile conditions
- asexual reproduction
- germinate quickly
ECOLOGICAL SUCESSION
secondary sucession
- starts from bare soil with a previous community
- process will be quicker due to having soil
ECOLOGICAL SUCESSION
whats a climax community
whats a plaigoclimax community
- stable community at the end of ecological sucession
- area where the influneces of humans have prevented ecosystems from developing further eg: by mowing, grazing and burning. stopped reaching climax community
ECOLOGICAL SUCESSION
overall discribing sucession
- pioneer species such a s lichens are able to colonise in hostile environments
- they chnage the abiotic conditions = less hostile, more stable
- this allows more species to grow, and it is now less suitable for pioneer species
- new species can outcompete pioneer species
- overtime many species flourish = climax community
MARK - RELEASE - RECAPTURE
equation
first marked / total = caught marked / 2nd pop
MARK - RELEASE - RECAPTURE
assumptions
- the roportion of marked to unmarked in 2nd sample = marked to unmarked as a whole
- makes individuals when releaced distribute themselves evenly amoungst the remainder of the population
- no immigration or emmigration
- no birth or death occours
- method of marking isnt harmful and doesnt affect predation
- mark isnt lost or rubbed off