biodiversity Flashcards
define biodiversity
refers to variety and complexity of life
indicator in study of habitats
define biodiversity hotspots
regions of that world that have a high biodiversity threatened by loss of biodiversity
what are the reasons for maintaining biodiversity
ecological
economical
aesthetical
what levels are biodiversity considered at
genetic
species
habitats
what does every organism in an ecosystem have
niche
define ecology
study of interactions between organisms
give 4 examples of habitat biodiversity
woodlands
meadow
streams
sand dunes
define community
population of all species in a habitat
define population
number of organisms of each species
how are species biodiversity measured by
species richness – number of species in an area
species evenness – relative abundance of species in an area
what does habitat biodiversity refer to
number of different habitats found within an area
therefore, greater species biod. too
what does species biodiversity refer to
richness and evenness
what does genetic biodiversity refer to
variety of genes that make up a species
different alleles exist for a gene which leads to genetic biodiversity
higher genetic biod. allows a better adaptations to a changing environment
define succession
process by which ecosystems change over time
how does succession occur
changes to the environment causing plant and animal species present to change
define primary succession
occurs on area of land newly formed or exposed (bare rock)
define secondary succession
occurs on land where soil is present but contains no animal or plant species
give examples of primary succession
volcano erupt
sand blown by wind
silt and mud
glaciers retreating
describe the role of a pioneer species
arrive as spores/seeds carried by wind that colonise the bare (rock) environment
give an example of a pioneer
lichen
stable symbiotic organism of fungi and algi
what are the adaptations of pioneers
produce large quantities of seeds or spores
seeds that germinate rapidly
phototrophic
tolerant to extreme environments
fix nitrogen from the atmosphere
(adding the mineral content of the soil)
what is humus
result of pioneers dying and decaying
their organic products release into the soil
give an example of a secondary coloniser
moss
give an example of a tertiary coloniser
plants (fern)
what happens as you go through each seral stage
rock continues to be eroded and the mass of organic matter increases
what happens to the soil as time goes by
contribute to a deeper and nutrient-rich soil, which retains more water
makes abiotic conditions favourable for flowering plants, then trees when the soil is deep enough
how do species succeed previous species in the intermediate community
different plant and animal spceis are better adapted to the current conditions in the ecosystem
these species outcompete species previously present
what is the final seral stage called
climax community
stable state showing little change over time
suggest why the climax community sometimes isn’t the most biodiverse
dominant species out-competing pioneer and other species, leading to their elimination
describe the lichen
xerophyte
secretes acid which breaks down rock into soil
define deflated succession
when succession is stopped artificially
the final stage is called plagioclimax
give examples that cause deflated succession
grazing of vegetation
removing existing vegetation to plant crops
why do we measure biodiversity
allows comparison between different areas and the same areas at different times
what does a sample have to be
representative
not over estimate biodiversity
covers full range of species
what does the sampling method depend on
accuracy
sample size
time of study and how long it’s been investigated
nature of organisms being sampled
describe random sampling
where each individual in the population has an equal chance of selection
mark out a grid using tape measures laid out perpendicular to each other
use random coordinates and take a sample at each of the coordinates generated
may not cover all areas of a land equally
describe opportunistic sampling
selecting individuals that are available
describe stratified sampling
number of samples in an area are proportional to its size
followed by a random sample in the area
describe systematic sampling
samples taken at fixed intervals
used when an area is varied or when to look at change (using a belt or line transect)
what are some limitations to sampling
- time of day
- not identifying species correctly
- not replicating
how do we increase the reproducibility of a sample
use standard procedure
sample many times then calculate the mean
sample at different times/weather conditions`
what qualitative technique can we use when using a line transect
ACFOR scale to measure species abundance
what are some techniques to sample animals
sweep nets
pooters
tree beating
pitfall traps
define species richness
number of species in an area
define species evenness
relative abundance of each species in an area
what are issues with sampling
sampling bias
chance
what are examples of sampling animals
pooter
sweep nets
tree beating
pitfall traps
kick sampling (for rivers)
