chapter3 evsc222

chapter3 evsc222 - EVSC 222 chapter 3 Biodiversity is the...

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EVSC 222- chapter 3 Biodiversity is the term used to describe all the variation among living things on earth. o Also includes variation within a species when differences between members of the species are caused by genetic variation. Common way to evolve separate, genetically distinct populations is when species exist over a wide range of environmental conditions. To capture the full diversity of a species, all the different types must be included. How many species are there? o 1.4 million species of plants and animals described by science. o No one knows how many species there are on earth, estimates range from 4-100 million species. o We believe 90% of vertebrates have been described. o Range of insects and invertebrates vary widely. o Insects make up largest taxon of global diversity; it makes estimates of total species diversity highly speculative. o 1982- Terry Erwin, of national museum of natural history--- developed a system for “fogging” the canopy of a tree with insecticide. First step: select suitable tree and surround it with 1m diameter funnels to catch insects Once fogging started, the poison gas killed all the insects in canopy of tree fell into funnels and were preserved in alcohol. After fogging Luchea seemanii--- 163 species of beetle that were found only in this species of trees.
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From his findings he reasoned total number of insects is likely to be closer to 30 million. 50,000 species of trees, 8,150,000 species of beetles. (163*50,000) o Beetles make up 40% of all types of known insects. o
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chapter3 evsc222 - EVSC 222 chapter 3 Biodiversity is the...

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