A4.2- conservation of biodiversity Flashcards
ecosystem diversity
variety of environments
species diversity
number and different species present in an ecosystem
genetic diversity
variety of gene pool within a species
comparison between number of species and past levels of biodiversity
10–100 million species exist on Earth
evidence from fossils suggest that there are currently more species alive on earth today than at any time in the past
anthropogenic causes of 6th mass extinction
-overharvisting
-habitat destruction
-invasive species= when alien species are introduced into an ecosystem and drive native species extinct
-pollution
-global climate change
three case studies of extinction
1) Caribbean monk seal- native marine mammal to Caribbean sea, but has not been sighted for over 70 years. It was hunted for oil, and overhunting on the coral reefs in which they fed-leading to starvation. Easy target because it would break on beaches, no fear of humans, slow
2) Giant moa- tall bird native to north islands of New Zealand which was uninvaded until humans entered in 13th centaury. Took less then 200 years for Moa to be hunted to extinction for meat
3)Silphium-plant that grew in Libya which became extinct a few hundred years after ancient Greek arrival, who used it for birth control
two case studies of ecosystem loss
1) MD forest in Southeast Asia (MDF) Dipterocarps are a family of trees found in large areas of southeast asia- high in diversity. MDF has high quantities of timber and used for logging. Since 1970s, most areas of MFS have been lost due to land conservation to oil plantations. These plantation release CO2 into atmosphere.
2) loss of aral sea- larges lake between kazakstan and uzbekistan that was fed by two rivers, no flow out. In 1960, two major rivers that fed aral sea were diverted and water levels fell and became dessert. Many fish endemic
evidence for biodiversity crisis
evidence can be drawn from IPBES reports and sources
-results from wide ranges of habitats around the world are required
-surveys need to be repeated to provide evidence in change;
-species diversity
-richness and evenness of biodiveristy
-area occupation
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IUCN red list
list established to update the list of world threatened species-has trusted info
causes of biodiversity crisis
-overpopulation as overarching cause;
-hunting
-urbanization
-deforestation
-pollution
-spread of pests
-alien invasive species due to global transport
what is a hotspot
The richest and most threatened reservoirs of plant and animal life on earth.
criteria’s to identify hotspots
The number of species present.
The number of those species found exclusively in an ecosystem.
The degree of threat they face.
what is extinction
last member of a species dies and the species vanishes forever from Earth
what is extirpation
disappearance of a particular population, but not the entire species globally
what are endemic species
species vulnerable to extinction
