definitions Flashcards
(17 cards)
biodiversity
-measure of the variation found in the living world
-such as organisms and the ecosystems they’re part of
-can be measured in terms of genes/species/habitats
what’s an ecosystem
a community of organisms and abiotic components
community
2 or more populations of different species living in an area
what’s habitat diversity
a measure of how many different habitats are present in an area
-such as sand dunes, woodland, streams, etc
what’s species diversity
-measure of how many different species are present in an area and how many individuals of these species there are
what’s species richness
-the number of different types of species in a particular area
-doesn’t take into account the number of individuals of a particular species
what’s species evenness
comparison of the size of the population
-such as the number of individuals of different species within a particular area
what’s genetic diversity
-measure of how many variations (alleles) there are in the genetic code
-either between individuals of a particular species or between different species
-it can create breeds within a species
why measure biodiversity?
-to compare different areas to see which requires most protection (funding)
-compare the same area but at different times (such as comparing biodiversity of group of fields before/after hedgerows have been removed or in summer vs winter)
random sampling advantage
ensures data are not biased by selective sampling
random sampling disadvantage
-may not cover all areas of habitat equally
-species w a low presence may be missed so underestimate biodiversity
non random opportunistic advantage
easier + quicker than random
non random opportunistic disadvantage
-data may be biased
-presence of large/ colourful species may entice researcher to include that species so overestimate biodiversity
non random stratified advantage
-ensures all different areas of a habitat are sampled and species are not under-represented
non random stratefied disadvantage
-possibility that it may lead to over representation of some areas in sample
-disproportionate number of samples taken in smaller areas that look different
non random systematic disadvantage
-only species on the line/within the belt can be recorded
-other species may be missed leading to underestimate
non random systematic advantage
-useful when habitat shows clear gradient in environmental factors such as getting drier further away from a pond
