BIOC51H3 Lecture 6: BGYB51H3 Lecture 6 Notes Sep 29
11 Aug 2010
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BGYB51H3 Lecture 6 Notes
-in natural experiments, introduction of new host species are observed in an area to determine
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-introduction of new host can cause little competition initially compared to original host that
suddenly experiences more competition (e.g. soapberry bugs)
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-in Galapagos Islands, a single lineage of finches underwent an adaptive radiation which
diversified their beak characteristics and body sizes as a result of different niches and food
-before the drought in the Galapagos Islands, natural selection favoured birds with small beaks
-during the drought in the Galapagos Islands, natural selection favoured larger birds with bigger
beaks
-offspring of survivors of the drought had larger beaks and large body sizes
-in the second drought, there was increased competition between large competitors, providing
an advantage for smaller birds
-evolution is dynamic in that populations can change repeatedly (or change in one direction,
then back again)
-environment changes bring selective pressures to cause evolutionary changes
-inferred causation increases when multiple events involving selective pressures correlate with
each other
-microevolution occurs today and causes changes in genotype frequencies
-macroevolution are changes that distinguish higher taxonomic groups
-sperm competition among different primates occurs in order for fertilization of eggs of a single
female (occurs if females mate with more than 1 male)
-large testes evolved in male primate species where females mate with more than one male
-using different primate species as independent data points overinflates the sample size by not
considering them being one evolutionary event that occurred
-an evolutionary event in primates involved changes in mating system that led to evolution of
different size in testes
www.notesolution.com
Document Summary
In natural experiments, introduction of new host species are observed in an area to determine. Introduction of new host can cause little competition initially compared to original host that suddenly experiences more competition (e. g. soapberry bugs) In galapagos islands, a single lineage of finches underwent an adaptive radiation which diversified their beak characteristics and body sizes as a result of different niches and food. Before the drought in the galapagos islands, natural selection favoured birds with small beaks. During the drought in the galapagos islands, natural selection favoured larger birds with bigger beaks. Offspring of survivors of the drought had larger beaks and large body sizes. In the second drought, there was increased competition between large competitors, providing an advantage for smaller birds. Evolution is dynamic in that populations can change repeatedly (or change in one direction, then back again) Environment changes bring selective pressures to cause evolutionary changes.
