A4.2 Conservation of Biodiversity Flashcards
what is biodiversity
means the total number of different species living in a defined area or ecosystem
ecosystem diversity
the range of different habitats or number of ecological niches per unit area in an ecosystem
species diversity
the variety of species per unit area
includes the number of species present and their relative abundance
genetic diversity
the range of genetic material present in a gene pool or population of a species
richness
term that refers to the number of species in an area
evenness
refs to the relative abundance of each species
community with high evenness means what
similar abundance of all species, suggests complex ecosystem with many niches that support many species
low evenness suggests what
there is a handful of species dominating
simpsons reciprocal index
can be used to describe and compare communities
what should be considered when comparing communities
low diversity could indicate pollution, eutrophication or recent colonization of a site
number of species in an area is often indicative of general patterns of biodiversity
what is the estimation of numebr of species on earth
around 9 million in total
radiometric data
is able to show the age of fossils by measuring the amount of naturally occuring radioactive substances such as carbon 14
steps that a fossil undergoes
petrifiation - organic matter of the dead organisms replaced by mineral ions
organic matter decays, leaves a mould filled by mineral matter
impression is made and then preserved
anthropogenic
causes of species of extinction caused by humans
what were the north island giant moas
species of flightless birds found in new zealand
how did the north island giant moas go extinct
maori arrived in 1280 and they were hunted for food.
extinct by 1500
their habitats/forests were also cleared for farming
the effects of the extinction of giant moas
they were large so played a major role in shaping the structure and composition of vegetation communities
their extinction of moa could have affected new zealand’s ecosystems through altering vegetations composition and structure
caribbean monk seals
declared extinct in 2008
widespread distribution through seas of mexico, caribbean, atlantic etc
first seal to become extinct because of human causes
how did caribbean monk seals go extinct
hunted for fur, meat, blubber, display
overfishing activites also disrupted their prey
they were easy to kill because of tame behaviour
effect of caribbean monk seals going extinct
top predator so extinction meant some species of fish expanded at the expense of others, significantly altering the biodiversity of the areas where the seal had been found