long-term evolutionary experiments chapter 6
DESCRIPTION
LONG-TERM EVOLUTIONARY EXPERIMENTS CHAPTER 6. http://natsci.edgewood.edu/wingra/Student%20Projects%202008/E.%20Coli/default.htm. ADAPTIVE RADIATION STUDIES PROVIDE LIMITED INFORMATION AS TO WHY IT HAPPENED AND WHAT OTHER POSSIBILITIES MAY HAVE BEEN POSSIBLE. - PowerPoint PPT PresentationTRANSCRIPT
LONG-TERM EVOLUTIONARY EXPERIMENTS
CHAPTER 6http://natsci.edgewood.edu/wingra/Student%20Projects%202008/E.%20Coli/default.htm
ADAPTIVE RADIATION STUDIES PROVIDE LIMITED INFORMATION AS TO WHY IT HAPPENED AND WHAT OTHER POSSIBILITIES MAY HAVE BEEN POSSIBLE.
CLASSICAL STUDIES: GALAPAGOS FINCHES, AFRICAN CICHLIDS, STICKLEBACKS
http://news.nationalgeographic.com/news/bigphotos/83795719.html
THE THEORY OF EVOLUTION BY NATURAL SELECTION PROVIDES A CAUSE-AND-EFFECT FRAMEWORK (EVEN MATHEMATICALLY) BUT
NOT THE MECHANISMS.
SHORT-TERM SELECTION VERSUS LONG-TERM STUDIES
SHORT-TERM• limited number of generations• Can lead to erroneous inferences
regarding genetic correlations
LONG-TERM• Association of organism and
environment is open-ended• Direct investigation of why an
adaptation happened (causality)• Model organisms - insects
(Drosophila) or microbes (E. coli) www.nature.com
• Long-term studies are able to study the importance of chance impacts on adaptation
http-//louisproyect.wordpress.com
CLONAL INTERFERENCE MAINTAINS DIVERSITY
Periodic selection : natural selection recurrently purges diversity within a bacterial population
Recombination in bacteria is rare
Diversity is generally transient
Larger populations (possible via long-term studies) >>
multiple beneficial mutations>> diversity persists
3 ways ( Dr. Bennett)
http-//www.nature.com/nrg/journal/v4/n6/box/nrg1088_BX2
ADAPTIVE RADIATION:Trade-off between resource
breadth and competitive ability• Organism may be
good at using one resource and not another>>>leads to co-existence of species
http://natsci.edgewood.edu/wingra/Student%20Projects%202008/E.%20Coli/default.htm
SUMMARY
Long-term studies • direct observation of
adaptation• mechanisms of
adaptation• evaluation of
environmental and genetic factors
• causality of evolutionary change
References• http://abcnews.go.com/Technology/DyeHard/climate-change-find-tiny-stickleback-
fish-evolved-temperatures/story?id=11368797• http://www.plosbiology.org/• http://www.biomedcentral.com/1471-2148/10/11• http://beaker.biology.washington.edu/research/pubs/2002/Bohannan_et_al2002.pdf• http://www.hhmi.org/genesweshare/e120.html• http://www.nature.com
• http://www.nanobugs.com/• http://www.ncbi.nlm.nih.gov• http://news.nationalgeographic.com/news/bigphotos/83795719.html
http://www.plosbiology.org/article/info:doi%2F10.1371%2Fjournal.pbio.1000250