O T T F F S S E __ What comes next?
9 I V E I X EVEN IGHT NINE 1 2 3 4 5 6 7 8 O T T F F S S E __ N E W O H R E E O U R It’s EASY if you know the PATTERN! (Just like Punnett Squares)
Interest Grabber Section 11-2 Tossing Coins • If you toss a coin, what is the probability of getting heads? Tails? If you toss a coin 10 times, how many heads and how many tails would you expect to get? Working with a partner, have one person toss a coin • ten times while the other person tallies the results on a sheet of paper. Then, switch tasks to produce a separate tally of the second set of 10 tosses.
Interest Grabber Answers • Assuming that you expect 5 heads and 5 tails in 10 tosses, how do the results of your tosses compare? How about the results of your partner’s tosses? How close was each set of results to what was expected? • Add your results to those of your partner to produce a total of 20 tosses. Assuming that you expect 10 heads and 10 tails in 20 tosses, how close are these results to what was expected? • If you compiled the results for the whole class, what results would you expect? • How do the expected results differ from the observed results? Results will vary, but should be close to 5 heads and 5 tails. The results for 20 tosses may be closer to the predicted 10 heads and 10 tails. The resultsfor the entire class should be even closer to the number predicted by the rules of probability. The observed results are usually slightly different from the expected results.
PROBABILITY ____________________is the __________ that a particular _________________ likelihood event will occur It can be written as a: Fraction ____ Percent ____ Ratio ____ 1/4 25% 1:3
http://www.arborsci.com/CoolStuff/CoinFlip.jpg COIN FLIP There are 2 possible outcomes: HEADS TAILS The chance the coin will land on either one is: ____ ____ ____ Alleles segregate randomly just like a coin flip. . . So can use probability to predict outcomes of genetic crosses. 1/2 50% 1:1
PROBABILITIES PAST DON’T FUTURE If last coin flip was heads… there is still a 50/50 chance the next flip will be heads too. _____ outcomes ______ affect _________ones _____________works ______ in ___________ a ________ number of events. Probability predicting best large The more flips. . . The closer results will be to the expected 50:50 average.
DOMINANT/RECESSIVE Dominant capital _____________ allele is represented by a ____________ letter.(usually the first letter of the trait) ____________ allele is represented by the SAME _________________ letter. EX: Tall = ______ Short =______ Recessive lower-case T t NOT S for short
HOMOZYGOUSHETEROZYGOUS When both alleles in the pair are the _______, the organism is _______________ or __________ EX: ____ or ___ When both alleles in the pair are _____________, the organism is _________________ or _____________ Ex: ____ SAME HOMOZYGOUS PURE TT tt DIFFERENT HETEROZYGOUS HYBRID Tt
PHENOTYPE/GENOTYPE genetic makeup The ________________ of an organism is its _____________ The ____________of an organism is its _____________ GENOTYPE appearance PHENOTYPE
MAKING A CROSS for only a __________ trait =____________________ ONE GENE A Punnett square for a MONOHYBRID CROSS looks like this: MONOHYBRID CROSS
PUNNETT SQUARES are used to show possible offspring from a cross between 2 parents _______________ go at top and on left side Boxes show _______________________________ Parent alleles T T T t possible offspring combinations
STEPS FOR MAKING CROSSES Figure out parent alleles Choose Punnett size Put in parent gametes Fill in offspring combinations probabilities phenotypes genotypes 1. ___________ what _________________ are 2. ________correct__________ square __________ 3. ______ possible_______________________ 4. ______ boxes with _____________________ 5. Determine ____________of_____________& ____________
IN PEA PLANTS T Tall is dominant over short TALL = ____ SHORT = ____ t LET’S MAKE A CROSS! PURE TALL PURE SHORT X
PURE TALL parentWhat are the parent alleles? TT _________ HOMOZYGOUS What gametes can it make? T T
PURE SHORT parent What are the parent alleles? HOMOZYGOUS tt _________ What gametes can it make? t t
T T t t ALL _____ of the offspring ____ % ___/4 will be Tt T t 100 4 Tt Tt Tt TALL GENOTYPE _____ PHENOTYPE _______
HYBRID TALL parent What are the parent alleles? Tt _________ HETEROZYGOUS What gametes can it make? T t
T t TT T T t TT GENOTYPES ¼ = _____ ½ = _____ ¼ = _____ Tt tt Tt tt t 3/4 75 TALL PHENOTYPES ____ or ____% _________ ____ or ____% _________ 1/4 25 SHORT
PRACTICE MAKING GAMETES for a MONOHYBRID CROSS R Tall = ____ Round seeds = ___ Short = ____ Wrinkled seeds = ___ T t r
What are the possible gametes? Homozygous Tall parent = What gametes can it produce? T T T T
What are the possible gametes? PURE wrinkled parent = What gametes can it produce? rr r r
What are the possible gametes? Heterozygous Round parent = What gametes can it produce? R r R r
What are the possible gametes? Hybrid Tall parent = What gametes can it produce? Tt T t