Bio 321 F13 lecture 3 v2

For each sex based on charnov bull model 10 proportion

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Unformatted text preview: SD" " •  " " What would you predict about fitness and temperature for each sex based on Charnov-Bull model?" 1.0" Proportion of males" •  slide from J. Wiens In this species, TSD is Type II (males at intermediate temperatures, females at low and high)" 0.5" 0" 20" Temperature ºC" 40" TSD/GSD" Testing Charnov-Bull model" •  •  " " In 2003, started with 221 eggs from 41 clutches, divided eggs into 3 " groups, incubated each group at different temp (23, 27, 33 º C), Basic experimental design in Warner & Shine (2008)" made half of each group male (used aromatase inhibitor)" •  Genotyped hatchlings using molecular markers, put hatchlings in mixed enclosure (30–32 individuals, ~10 from each group) " •  Let hatchlings grow up and breed, determined how many individuals in next generation were fathered by males from each group using molecular markers" slide from J. Wiens TSD/GSD" REMINDER" % males" What do the results show?" " " " temperature" # offspring in 2005-2006" # offspring in 2006-2007" Lifetime reproductive success" slide from J. Wiens TSD/GSD" What explains these results?" " " " Results for 2005-2006" •  More larger males breed successfully " •  Larger males hatched earlier" •  Lizards incubated at warm temperatures hatched earlier" slide from J. Wiens Results for 2006-2007" TSD/GSD" " What might the disadvantages of TSD be?" " " slide from J. Wiens TSD/GSD" " What might the disadvantages be? " •  " In an endangered species of sea turtle (Loggerhead; Care8a care8a) 94% of hatchlings over 3- year period were female •  In painted turtles (Chrysemys picta), es0mated that increase in global temperature by 4º C would eliminate all males slide from J. Wiens TSD/GSD" " " •  Some people have suggested that dinosaurs had TSD and that they went " ex0nct because climate change affected the sex ra0os •  Hard to tell if dinosaurs had TSD (turtles and crocodilians do, birds don’t) slide from J. Wiens genotypic sex determina0on •  can be one locus –  e.g. Saccharomyces cerevisiae – a, α •  in animals – sex chromosomes systems most common –  insects and mammals: females XX, males XY (or X0) –  birds and buZerflies: females ZW, males ZZ (or Z0) •  haplodiploid sex dermina0on –  eusocial insects (bees, ants, termites) –  females diploid (from fer0lized eggs), males haploid (from...
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