bio chap 47 biodiversity

less than ____ of organisms on earth have been described and named

20%

what rates determine biodiversity over time

speciation and extinction rates

increased speciation means

birth; so more species

increased extinciton means

death; fewer species

ordovician-silurian mass extinction

life was almost exclusively in oceans - 85% extinct - caused by glaciation followed by extreme warming

devonian extinction

affected marine, not terrestrial; cause not understood

permian extinction

largest extinction event on earth, 96% marine and 70% terrestrial extinct, dramatically altered course of evolution

triassic-jurassic

85% extinct, cause unknown but happened right before pangaea broke apart

cretaceous extinction

all dinos extinct except the theropod clade, caused by asteroid impact off yucatan peninsula and volcanic activity→ mammals became dominant after this

holocene extinction

coincides w expansion of european colonies around world - 400 yrs - present. dodo bird, stellars sea cow, etc. extinction rate is increasing exponentially

international union for conservation of nature

Global authority on species conservation

• Monitors threats to species

• Classifies species as critically endangered, endangered or

vulnerable

convention on international trade in endangered species of wild fauna and flora

Illegal pet trade threatens many species

• CITES prevents capture and transporting of 33,000 species

• Only as good as individual country’s ability to prosecute traders

US endangered species act and north american migratory bird treaty act

ESA protects species that are listed as critically endangered or

endangered

• MBTA protects 800 species of birds

• Illegal to kill, disturb, and transport birds or parts of birds