NATS 1940 Lecture Notes - Lecture 28: Allopatric Speciation, Dna Barcoding, Species Richness
28 Jan 2020
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Document Summary
Isolation of island populations allows for allopatric speciation to take. Species unique to a specific geographic location. Initially new species are endemic to that island (not found elsewhere) Later may spread to other islands or inland. Which is a cluster of islands or chain of islands. Lead to many opportunities for isolation which results in high speciation rates. The hawaiin islands contain 90% of plant species that are endemic. High diversity is due to variations in climate, vegetation patches by lava flow. Older islands (west) generally contain species ancestral to younger islands (east) Most islands species are not endemic (arrive by dispersal) More isolated islands lower colonization rate. Species richness tends to decrease with higher isolation. Increase in endemic species but a decrease in species richness. In absence of competitors, island species may occupy new habitats. Nests in shady grounds but also in open soil and tree trunks. Not evolutionary change but simply the release from competition.
