GEOGRAPHY NOTES ÃÂ· Since European settlement between 78 & 100 plant species have become are extinct. 150-200 under threat.
ÃÂ· GENETIC DIVERSITY - safeguard species diversity. Large range of genetic forms within each species. Genetic variations.
ÃÂ· Extinct- disappearance of species after thorough searching (some extinction is natural) ÃÂ· At risk- in danger of becoming extinct ÃÂ· Endangered- close to extinction in the wild unless something is done the species could disappear altogether ÃÂ· Vulnerable- The step before endangered ÃÂ· Rare- few of a particular species remain , less serious category than endangered ÃÂ· Extinction can occur naturally because of climatic change which affects the vegetation on which animals depend.
ÃÂ· MEGAFAUNA-large Australian mammals from the ice age ÃÂ· Aborigines 50000 yrs ago modified asia Australia bridge vegetation through burning it out resulting in dry arid landscapes. This also could have made extinct the megafauna.
ÃÂ· In Aus since 1788 only 30% of the vegetation remains unmodified to osme degree.
ÃÂ· Cultural Vegetation means exotic or introduced species, such as those found in ornamental gardens or pine plantations.
ÃÂ· The murray darling was dammed affecting surrounding habitats ÃÂ· Introduced species have had a 3 fold effect on environments 1. Grazing 2. Competition between native and introduced species 3. introduced species can introduce formerly unknown diseases.
ÃÂ· In recent years large amounts of insecticide and weedicide have been used and effect the food chain ÃÂ· Homozygosity- breeding of the same species of animals ÃÂ· Hybridise- mixed breeding of plants ÃÂ· Wildlife is harmed by recreation practises ÃÂ· Oldest nat. park in Australia is Witches Falls in QLD founded 1908.
ÃÂ· Rachel Carson's SILENT SPRING showed the impact that pesticides could have in areas far outside where they were applied.
ÃÂ· We are using up our renewable resources faster than we...