Creedon 1 Brendan Creedon 280 Evolution Adam Porter 9 30 2015 Joaquin is the hurricane if there is weather effects exam will take place 10 7 Exam is in class You are allowed to bring a calculator You cannot program it Welcome to Bio 280 Evolution Instructor Dr Adam Porter aporter bio umass edu of ce hrs TODAY Wed 5 6 PM or email me to set up a better time rm 440 Morrill I North Bldg uphill side Trusty TA Scott Schneider scotts psis umass edu of ce hrs Thursdays 5 6 pm in 104 Fernald Hall or email to set up a time 1st midterm Monday 10 5 in class bring a calculator if you want no programming it no phone tablet calculator apps NO MAKEUPS AFTER THE EXAM Need a makeup exam see me after class 2 review sessions both in this room Thursday 10 1 5pm Sunday 10 4 6 30 pm Long shot if Joaquin closes school Monday exam moves to Wed 10 7 Reload Parent phenotypes RR homozygote RESISTANT to pesticide survives RS heterozygote it depends SS homozygote SUSCEPTIBLE dies RR Creedon 2 RS SS chance an individual gets killed NEW resistant mutations arise in population parent genotype frequencies birth 0 000001 0 001 0 999 0 25 100 parents killed 99 925 Very effective pesticide Offspring new mutant R allele freq 0 5 Resistance evolves rapidly New spray eld with HIGHER dose Parent phenotypes RR homozygote RESISTANT to pesticide survives RS heterozygote it depends SS homozygote SUSCEPTIBLE dies RR RS SS chance an individual gets killed NEW resistant mutation arises in population parent genotype frequencies birth 0 000001 0 001 0 999 99 9 100 0 Parent generation Q What fraction of the parents will be killed Creedon 3 1 0 9991 2 0 9995 3 0 999999 Parent generation Q What fraction of the parents will be killed 1 0 9991 2 0 9995 3 0 999999 extremely effective Offspring generation Q What s the frequency of the new mutant resistant R allele 1 0 002 2 0 005 3 0 05 4 0 5 Q What s the frequency of the new mutant resistant R allele 1 0 002 2 0 005 3 0 05 4 0 5 Offspring generation About how big does the does the beetle population have to be in order to leave enough resistant survivors to breed 2 000 000 Even this won t be good enough Need another trick leave part of eld untreated pesticide free refuge Parent phenotypes RR homozygote RESISTANT to pesticide survives RS heterozygote it depends SS homozygote SUSCEPTIBLE dies RR RS Creedon 4 100 0 999 SS chance an individual gets killed in treated area 0 chance an individual gets killed in refuge 0 0 0 NEW resistant mutation arises in population parent genotype frequencies birth 0 000001 0 001 0 999Q What s the frequency of the new mutant resistant R allele 1 really low near 0 2 0 5 1 really low near 0 Jargon allele can become xed allele freq 1 0 lost allele freq 0 Evolutionary rate how much allele frequency changes in a generation usually on average or over some time period or a trait changes Other ways evolution happens Recall Natural selection requires 3 conditions 1 Individuals are different 2 Some variants have more offspring than others because of those differences 3 Individuals inherit their differences I said any condition missing no change next generation I oversimpli ed change still possible lucky differences in reproductive success can change allele frequencies unpredictably bad luck accidental deaths etc Creedon 5 good luck extra offspring survive etc Recall 4 ways evolution works Natural selection winning the baby game Mutation when genes change Genetic drift evolution by luck Gene ow evolution when genes travel all operate at once Genetic Drift evolution by pure luck 1 Individuals are different 2 Some variants have more offspring than others because of those differences just because of luck 3 Individuals inherit their differences Example a population with 4 genotypes L D P T neutral alleles none better than others frequency of each allele Teletubby life cycle Creedon 6 Grow into adults Lay many many eggs only 4 random eggs hatch starts next teletubby generation 4 random eggs hatch starts next teletubby population Q This means that 1 each random egg has an equal chance to be L D P T 2 each color of telletubby will be present in the next generation 3 both 4 neither Q This means that 1 each random egg has an equal chance to be L D P T 2 each colored telletubby will be present in the next generation 3 both 4 neither Evolution in teletubbies generation 1 Creedon 7 Four eggs hatch Coin ips H H parent 1 H T parent 2 T H parent 3 T T parent 4 teletubby 1 teletubby 2 telletubby 3 teletubby 4 original population Laa Laa http www teletubbies co uk en Dipsy Po Tinky Winky Coin ips H H parent 1 H T parent 2 T H parent 3 T T parent 4 teletubby 1 teletubby 2 telletubby 3 teletubby 4 original population Laa Laa http www teletubbies co uk en generation 1 Four eggs hatch What is the new frequency of the L allele in generation 1 1 need more information 2 1 0 3 0 75 4 0 5 5 0 25 6 0 Creedon 8 Dipsy Po Tinky Winky generation 1 Generation 2 Four eggs hatch Coin ips H H parent 1 H T parent 2 T H parent 3 T T parent 4 teletubby 1 teletubby 2 telletubby 3 teletubby 4 original population Laa Laa Dipsy Po Tinky Winky generation 1 generation 2 Allele frequencies change in big steps evolutionary rate high rapid loss xation How to study this section run the animation at the different settings and see random evolution drift in action Ask Why do the patterns change when I change the settings Creedon 9 What about bigger populations Population of 8 hamsters 1 2 white 1 2 gray 1 gene copy hamster white allele gray allele Graph frequency of the white allele Q What is the white allele frequency next generation offspring 1 randomly choose parent offspring 2 randomly choose parent etc Evolution in big steps with 8 hamsters Each gene copy worth 1 8 of total 12 5 Evolution by luck goes fast random direction Q How fast is genetic drift in larger populations 50 hamsters 100 hamsters 500 hamsters Slower in larger populations Each parent s copy of an allele worth 1 50 of total 2 1 100 of total 1 1 500 of total 0 5 Q What if the frequencies are not 50 white 50 gray 10 hamsters 7 white alleles Creedon 10 white xed only allele present more often Q What if the allele is rare like a new mutation would be 10 hamsters 1 white allele Mostly lost goes extinct sometimes xed xed 1 10 of the time What about sexual reproduction random mating random genes in eggs sperm more bookkeeping to do same result Q By genetic drift bigger populations evolve smaller populations 1 faster than …