T7 Pop Flashcards
Define succession
the process by which an ecosystem changes over time
Key stages of succession
colonisation by a pioneer species
changes abiotic conditions- less hostile
environment becomes more suitable for other species
less suitable for others
better adapted species outcomes previous
process occurs many times
increasing biodiversity
climax community reached- finial stable community
Estimating the size of a motile population
Mark-release-recapture
capture a sample of the population, mark them ( ensuring the make does not effect their chances of survival)
leave enough time for marked individuals to disperse into the general population
capture a second sample, count the number of marked individuals
Assumptions of mark-release-recapture
sufficient time given for pop to mix
marking does not affect survival chances/ not removed
no emigration
no death/ births
Estimating population size of slow/ non-motile species
randomly placed quadrants
quadrants systemically placed along a transect
Estimating population size using quadrants
place two tape measures perpendicular to one another
generate random co-ordinates using a random number generator
place quadrants at generated co-ordinates and count the frequency of species present in each quadrant
valuate mean per quadrants
mean x number of quadrants that would cover the whole area
Why use a transect?
when the environment is not uniform
effect of changing environmental conditions
changes in distribution
Define an ecosystem
A community’s interaction with abiotic conditions of their environment
Abiotic conditions
what are they? examples
Non-living factors of an ecosystem
pH, temperature, O2, H20, CO2, nutrient levels
Biotic conditions
what are they? examples
Living features of an ecosystem
How organisms interact with each other
Predation, interspecific competition, infraspecific competition, diseases
What does conservation involve?
the management of succession
prevents habitats from reaching their climax community
Define evolution
changes in allele frequencies in a gene pool over time
What is gene flow?
movement of genes from one population to another
What is the effect of high gene flow between two populations?
reduced genetic diversity between 2 pops
increased genetic diversity within each pop
What is genetic drift?
Changes in allele frequencies in a gene pool due to chance
