ENV-0007 Lecture Notes - Lecture 19: Biosphere 2, Species Richness, Ecosystem Services
6 Nov 2016
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Insects are the most numerous, perhaps 5-6 million: a(cid:374)other t(cid:449)o (cid:373)illio(cid:374) spe(cid:272)ies li(cid:448)e i(cid:374) the (cid:449)orld"s o(cid:272)ea(cid:374)s. Species richness and latitude: biodiversity varies by latitude, richness greatest near equator, speciation versus extinction, geographical area hypothesis: since the tropics have larger area, then these biomes can support more species. The more net primary production = the more species. Speciation: allopatric: occurs when biological populations of the same species isolated from each other to an extent that prevents or interferes with genetic interchange. Panama land bridge and snapping shrimp: peripatric: two populations isolated leading to new species, but one population is much smaller, parapatric: new species evolves, but from isolated new range that remains in contact with original population. Mutations w/in sub-populations: sympatric: the process through which new species evolve from a single ancestral species while inhabiting the same geographic region. Organisms whose ranges do not overlap, but are next to each other. Do not occur together except for narrow contact zone.
