T18 Biodiversity, Classification and Conservation Flashcards
species
group of organisms- similar morphology/ physiology. can reproduce to produce fertile offspring/ reproductively isolated.
habitat
where an organism, a population or community lives, defined by physical features/ abiotic characteristics.
population
all organisms in same species in a place, interbreeding.
community
all living organisms, all species, found in particular ecosystem at a particular time.
environment
factors affecting organisms in ecosystem, comprising of abiotic/ biotic.
ecosystem
self-contained, interacting community of organisms and environment they live and they interact.
ecological niche
role of an organism in the ecosystem
fundamental niche
niche an organism can occupy without competition.
realised niche
the niche an organism actually occupies in an ecosystem (w competition)
resource partitioning and competition
broad niche w one species that can be sectioned into two niches. intra-specific competition results in populations becoming more specialised to a particular aspect of the resource. if the population stops interbreeding then two new species will result.
abiotic factors
soil, atmosphere, water
biotic factors
producers, consumers, detrivores, decomposers
biodiversity
variety of ecosystems and species in an area and the genetic diversity within a species.
species richness
number of species
genetic diversity
diversity of genes within species
ecosystem diversity
refers to diversity at the ecosystem level
keystone species
species with a disproportionate effect on ecosystem stability because of pivotal role.
species evenness
proportion of individuals of each species in an area (relative abundance)
types of sampling
systematic, stratified, opportunistic
stratified sampling
divides the population into subgroups before sampling, mutually exclusive strata, used to highlight a specific subgroup
function of sampling
to gain data on composition and abundance
two factors to measure when investigating a species
distribution and abundance
methods of sampling when measuring abundance and distribution
point sampling, quadrats, line transects, belt transects, mark and recapture sampling
diversity indices function
quantify biodiversity in an area and can be used to measure ecosystem health
simpson’s index of diversity
D = 1-(sigma (n/N)^2)
N is total number of organisms
n is total number of organisms in a species
why is baseline data useful when interpreting a diversity index
allows you to compare the result of a diversity study and decide if diversity is greater or less or if has changed over time from place to place.
importance of recognising assumptions in investigations
allow for plausible explanations if results don’t support hypothesis, and recognise limitations of the investigation
quadrat sampling role
estimates population abundance, density, frequency of occurrence and distribution
estimated average density formula
total number of individuals counted/ (number of quadrats * area of each quadrat)
guidelines for quadrat use
area of each quadrat must be known enough quadrat samples must be taken population of each quadrat must be known size of quadrat must be appropriate must be representative of whole area
how to know how many quadrat samples to take
plot cumulative number of species recorded on y axis and number of quadrats taken on x.
point at which curve levels off indicates suitable number of quadrats required.
acronym for description of abundance
ACFOR
What does ACFOR stand for
abundant, common, frequent, occasional, rare
difference between animal and plant sampling
plant sampling can be done by quadrats, transects, abundance scales and percentage cover.
methods for animal sampling are more diverse and density is more commonly measured.
main consideration when determining quadrat size
must be large enough to be representative and small enough to minimise effort
advantages and disadvantages of staggering quadrat distances
allows for observation of a greater extent of trend
doesn’t allow for direct observation between two quadrats
the lincoln index
total population= (no. of animals in first sample * number of animals in second sample)/ number of marked animals in second sample
disadvantages of mark and recapture sampling
marked animals may die in the meantime
animals may not have mixed properly between marked and unmarked animals
can’t be used with immobile animals
assumptions in mark and recapture sampling
marking doesn’t affect survival
marked and unmaked are captured randomly
marks aren’t lost
animals aren’t territorial
methods for marking animals for capture recapture
banding on legs
tags on ears
paint/dye
function of the chi-squared test
compares sets of categorical data and evaluates if the differences between them are statistically significant.
aims to test the null hypothesis
what is the chi-squared test inappropriate for
small sample sizes
where do you enter data from a chi-squared test?
in a contingency table
how do you calculate expected values for a chi-squared test?
divide the row total by the grand total and multiply by the column total
chi squared formula
sigma: (O-E)^2 / E
O (observed value)
E (estimated value)
how to calculate degrees of freedom
(rows-1)*(columns-1)
