Beaks Of Finches State Lab 2020 Living Environment PDF

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Beaks of Finches State Lab Regents Requirements Living Environment 2020...

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Evolution in Action: Statistical Analysis

Activity Educator Materials

OVE OVERV RV RVIEW IEW This activity serves as a supplement to the film The Origin of Species: The Beak of the Finch and provides students with the opportunity to analyze data collected by Princeton University evolutionary biologists Peter and Rosemary Grant. The Grants have provided a random sample of morphological measurements, including wing length, body mass, and beak depth, taken from a sample of 100 medium ground finches (Geospiza fortis) living on the island of Daphne Major in the Galápagos archipelago. The complete data set is available in the accompanying Excel spreadsheet. This activity provides an example of how those data could be analyzed in class using statistical tests. In an extension activity, students are prompted to graph two of the morphological measurements against each other to investigate a possible association and propose an explanation for the association. KEY C CONC ONC ONCEP EP EPTS TS  Evolution by means of natural selection can only occur if heritable traits vary among individuals in a population.  In a given environment, individuals with one form of a trait may be able to better exploit some aspects of the environment than individuals with other forms of the trait can.  Natural selection involves the differential survival and reproduction of individuals with different heritable traits.  Evolution occurs when inherited traits in a population change over successive generations.  Graphing allows scientists to more readily identify patterns and trends in data.  Statistical tools provide a way to quantify variability in biological data and describe the degree of uncertainty in the results obtained using these data. ST STUDE UDE UDENT NT LEA LEAR RNI NING NG TAR TARGE GE GETS TS  Calculate descriptive statistics (mean, standard deviation, and 95% confidence interval) for multiple sets of data.  Use trend lines to show correlations between two variables.  Graph primary research data using both bar graphs and a scatter plot graph and appropriately label all graph components, including title, axes, units, and legend.  Evaluate the evidence provided by data sets in relation to a particular scientific question.  Determine the reliability of their sample mean with 95% confidence intervals.  State that error bars are a graphical representation of the variability of data.  Analyze the means between data sets with t-tests to determine the significance between data sets.  Construct explanations using evidence about the role of natural selection on morphological traits based on the measurements. CUR CURRI RI RICU CU CULU LU LUM MC CON ON ONN NECT ECTIO IO IONS NS Stan Standards dards NGSS (2013) AP Bio (2015) IB Bio (2016) AP Env Sci (2012) IB Env Systems and Societies (2017) Common Core (2010) Vision and Change (2009)

Curri Curriculum culum Con Connecti necti nection on HS-LS2-2, HS-LS4-3, HS-LS4-4 1.A.1, 1.A.4, SP1, SP2 5.2, C.1, C.5 II.A, II.C, III.A 1.2, 2.1 ELA.RST.9-12.7, ELA.WHST.9-12.1; Math.N-CN.2, S-ID.1, S-IC.1, S-IC.3, MP1, MP2, MP5 CC1, CC5, DP2

KEY TE TERM RM RMSS evolution, evolution of populations, natural selection, scientific process, speciation, statistics and math The Orig Origin in o off SSpec pec pecies: ies: Beak of tth he Finc Finch h www www.Bio .Bio .BioInt Int Intera era eractiv ctiv ctive.o e.o e.org rg

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TIM TIME E RE REQ QUIR UIRE EME MENT NT NTSS  Two 50-min classroom periods or one 90-min block period. Homework may be required.  The extension on correlations will require an additional 50 min.  Viewing the short film (15 min) prior to the activity is highly recommended and can be viewed at the beginning of class prior to starting the activity or assigned as homework.  Time requirements may differ depending on computer/internet access. SU SUGGES GGES GGESTE TE TED D AU AUDIE DIE DIEN NCE  High School: IB or AP Biology  College: Introductory Biology, Ecology or Evolution course PRI PRIOR OR KN KNOW OW OWLE LE LEDG DG DGE E  How to construct bar and scatter plot graphs  Basic understanding of descriptive statistics (mean, standard deviation, 95% confidence interval) and Student’s t-test  Basic understanding of making and justifying claims using experimental evidence  General understanding of genetic and evolutionary theory, including concepts like adaptation, fitness, and natural selection. MA MATER TER TERIA IA IALS LS  Scientific calculator if not using a computer with a spreadsheet program like Excel or Google spreadsheet  Graphing paper if not using a computer  Colored pencils for graphing if not using a computer  Ruler for graphing if not using a computer TEA TEACH CH CHING ING TI TIPS PS  It is highly recommended for students to view the film The Beak of the Finch (http://www.hhmi.org/biointeractive/origin-species-beak-finch) before doing this activity. Students may watch the film in class or as homework the day before.  You may choose to have students do the related activity “Evolution in Action: Graphing Activity” as an introduction to data analysis before performing the statistical calculations in this activity.  For additional background information on the Grants’ work, consult the In-Depth Film Guide available at http://www.hhmi.org/biointeractive/ .  You may wish to have students work in pairs.  If you are unfamiliar with interpreting the results of statistical tests, please refer to the Answer Key below for further explanation. You may also refer to the “Mathematics and Statistics in Biology” guide on the BioInteractive.org website. ANS ANSWE WE WER R KE KEYY PAR PARTT A A:: C Calc alc alcula ula ulatin tin tingg D Des es escrip crip criptiv tiv tive e St Stat at atisti isti istics cs See Table 2 on the next page for numerical answers to steps 1-4 in the student document. Note: Depending on the course, students can calculate either standard error of the mean or 95% confidence interval or both.

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Table 2. Descriptive statistics for morphological measurements taken from 100 medium ground finches (Geospiza fortis). The data are presented in two groups: birds that did not survive the 1977 drought (Nonsurvivors) and birds that survived the drought (Survivors). Nonsurvivors Survivors Body Mass (g) Descriptive Statistics Mean Variance Standard Deviation Standard Error of the Mean 95% Confidence Interval

15.71 1.842 1.36 0.19 0.38

Wing Length (mm) 67.79 5.181 2.28 0.32 0.64

Tarsus Length (mm) 19.04 0.701 0.84 0.12 0.24

Beak Depth (mm) 9.11 0.775 0.88 0.12 0.25

Body Mass (g) 16.99 3.087 1.76 0.25 0.50

Wing Length (mm) 69.30 5.448 2.33 0.33 0.66

Tarsus Length (mm) 19.35 0.735 0.86 0.12 0.24

Beak Depth (mm) 9.67 0.709 0.84 0.12 0.24

PAR PARTT B: Gr Grap ap aphin hin hingg the D Data ata 5. On a separate sheet of graph paper or on your computer, cons constru tru truct ct fou fourr b bar ar gr graph aph aphss that compare the means of nonsurvivors and survivors for each physical characteristic (body mass, wing length, tarsus length, and beak depth). Label both axes of each graph and show either the SEM or 95% CI as error bars, depending on your instructor’s directions. Note: Based on the course you are teaching, you can choose to have your students include either 95% CI bars or standard error of the mean in the graphs. Alternatively, you could have half of your students graph the 95% CI bars and the other half the SEM bars. Stud Studen en entt gra graphs phs sho shou uld look llike ike the on ones es sh show ow own n in FFigu igu igure re 1 b belo elo elow, w, in inclu clu cludin din dingg aappr ppr pprop op opriat riat riate e llabe abe abels ls ffor or ea each ch grap graph h.

Figu Figure re 1. Me Mean an bo body dy ma mass ss ((A), A), me mean an win wing g lleng eng ength th (B) (B),, m mean ean ttars ars arsus us leng length th ((C), C), and m mean ean bbeak eak dep depth th (D (D)) ccal al alcula cula culated ted fro from m 1100 00 me mediu diu dium m gr groun oun ound d fin finches ches (Geo Geosp sp spiza iza for fortis tis tis)) oon n tthe he isla island nd of Dap Daphn hn hnee M Majo ajo ajorr. Bars labeled “Nonsurvivors” represent 50 birds that did not survive the 1977 drought on the island. Bars labeled “Survivors” represent 50 birds that survived the drought.. In tthes hes hesee ggrap rap raphs, hs, er erro ro rorr bbars ars are 95 95% % conf confid id idenc enc encee in inte te terva rva rvals. ls. Stud Studen en ents ts cou could ld dra draw w the sam samee gra graph ph phss wit with h er error ror ba bars rs tha thatt ar aree sstan tan tanda da dard rd err errors ors of th thee m mea ea ean; n; they w woul oul ould d be aabo bo bout ut ha half lf th thee siz sizee of thes thesee err error or bbars ars ars.

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6. Once you complete your four bar graphs, describe any differences between nonsurvivors and survivors you observe in each graph. Stud Studen en ents ts sh should ould in indic dic dicat at atee th tha at all fou fourr m morp orp orpho ho holog log logica ica icall m meeas asurem urem uremen en ents ts fr from om th thee ssurv urv urvivin ivin iving g bbir ir irds ds aare re gre great at ater er tha than n th thee me measu asu asurem rem remen en ents ts for th thee nnon on onsu su survivi rvivi rviving ng bi birds. rds. So Som me sstud tud tudent ent entss m ma ay al also so ind indica ica icate te tha thatt tthe he 95% cconf onf onfide ide idenc nc ncee in inte te terval rval rvalss ffor or the non nonsu su survi rvi rvivo vo vors rs aand nd su surviv rviv rvivors ors ddo o nnot ot ov overla erla erlap p ffor or bo body dy mas mass, s, win wing g lleng eng ength, th, or bea beakk dep depth, th, su sugg gg ggesti esti esting ng tha thatt th thee diff differen eren erences ces bbet et etwee wee ween n th thee ttwo wo gro group up upss m may ay be re real. al. Ho Howev wev wever er er,, tthe he 95% cconf onf onfid id idenc enc encee in inte te terv rv rvals als ffor or ta tarsus rsus len length gth ddo o ove overla rla rlap p fo forr the two ggrou rou roups ps ooff bi birds. rds. D Dete ete etermi rmi rminin nin ning g wh wheth eth ether er the dif differ fer feren en ences ces aare re st stati ati atisti sti sticall call callyy ssign ign ignific ific ificant ant req requir uir uires es a stat statisti isti istical cal tes test, t, like th thee Stud Studen en entt t-t t-tes es est. t. PAR PARTT C: C Calcu alcu alculat lat latin in ingg t-Tes Testt SStati tati tatisti sti stics cs In this part of the activity, students are asked to calculate t-test statistics. Different types of t-tests are appropriate for different types of data. The one used in this activity, which is most often used in high school biology classes, is for independent samples and for data that are normally distributed. Samples are independent if the observations you make are not in any way linked to additional observations. For instance, measuring the wing length of 10 of the 50 survivors should not affect wing length measurements of the remaining 40 survivors. 7. Ca Calcu lcu lculate late tobs to comp compar ar are e the mean values of each physical characteristic between survivors and nonsurvivors. a. Use a graphing calculator, a spreadsheet program, or an online t-test calculator (many are available) to calculate tobs. Mean body mass: tobs = 4.08 Mean wing length: tobs = 3.2 3.27 7 Mean beak depth: tobs = 3.2 3.27 7 Mean tarsus length: tobs = 1. 1.82 82 b. How do your tobs for each pair of measurements compare to the critical t-value (tcrit) of 1.98? Th Thee me mean an bbody ody ma mass ss (tobs = 4. 4.08), 08), m mea ea ean nw win in ing g lleng eng ength th ((ttob 3.27), ), and m mea ea ean n bbeak eak ddepth epth (tobs = 3.2 3.27) 7) obss = 3.27 all exce exceed ed th thee ccritic ritic ritical al t-v t-valu alu aluee of 1. 1.98 98 fo forr a sam sampl pl plee ssize ize of 50 50.. Th Thee mea mean n ta tarsus rsus len length gth (tobs = 11.8 .8 .82) 2) do does es nnot ot exc excee ee eed d th thee criti critica ca call t-v t-val al alue ue of 1.9 1.98 8 ffor or a sa samp mp mple le siz sizee ooff 50 (i. (i.e., e., d. d.f. f. ooff 98 98). ). Note: The tcrit was determined using a calculation for the degrees of freedom (d.f.) of n1 + n2 – 2 = 98. 8. Analyze your four bar graphs, their associated error bars, and the results of your t statistic calculations. For each characteristic, make a claim about the differences you observe between survivors and nonsurvivors Support your claims with evidence from the graphs and statistics. Th Thee me mean an bbody ody ma mass ss (tobs = 44.08) .08) .08),, m mea ea ean nw win in ing g lleng eng ength th (tob 3.27), ), and m mea ea ean n bbeak eak ddep ep epth th ((ttobs = 3.2 3.27) 7) all exc exceed eed obss = 3.27 the cri critic tic tical al t-v t-va alue of 1.9 1.98 8 ffor or a ssam am ampl pl plee siz sizee ooff 50 50,, wh which ich me mean an anss tthat hat th thee ddiff iff ifferen eren erence ce cess bbet et etwee wee ween n nnon on onsu su surviv rviv rvivors ors aand nd surv survivo ivo ivors rs ffor or th thes es esee tr traits aits aare re sta statisti tisti tistica ca cally lly sign signifi ifi ifica ca cant. nt. On th thee ooth th ther er hhan an and, d, the mean ta tarsu rsu rsuss le lengt ngt ngth h (tobs = 11.82) .82) ddoes oes not exc exceed eed tthe he cri critica tica ticall t-v t-va alue of 1.9 1.98 8 ffor or a ssam am ample ple siz sizee ooff 550, 0, whi which ch me means ans ttha ha hatt th there ere is a ggrea rea reater ter th than an 0.0 0.05 5 pro proba ba babilit bilit bilityy ttha ha hatt th thee tobs of 1. 1.82 82 occ occurr urr urred ed by ch chanc anc ance. e. Note: If students have been instructed in statistical hypothesis testing, they may further explain that the large tobs values for body mass, wing length, and beak depth allow them to reject the null statistical hypothesis (H0) that the means are equal for each group of birds within each trait and that the small tobs value for tarsus length does not allow them to reject the null hypothesis for that trait.

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9. Based on what you saw in the film, id ident ent entify ify the adaptive trait that is most important to survival under the environmental conditions presented by the drought and su sugges gges ggestt a reason for the differences between the measurements taken from the birds that died during the 1977 drought and those from the birds that survived. Bea Beakk ddep ep epth th wa wass th thee tr trait ait uund nd nder er the mo most st in intens tens tensee nnat at atura ura urall sselec elec electio tio tion n gi give ve ven n the en envir vir viron on onme me menta nta ntall ch chan an ange ge of a lim limit it ited ed food aamo mo moun un untt aand nd ttyp yp ype, e, wh which ich ma made de it the tra trait it mo most st im imp port ortan an antt to su surviv rviv rviva al fo forr th thee ffin in inche che ches. s. IIn n th thee env enviro iro ironm nm nment ent crea create te ted d bbyy th thee dro droug ug ught, ht, ha havin vin ving g a la larg rg rger er bbea ea eakk w was as an ada adapti pti ptivve adv adva anta ntage ge an and d bbird ird irdss with la larg rg rger er bbea ea eaks ks wer weree m mo ore likel likelyy tto o ssurv urv urviv iv ive. e. LLarg arg argee bbeak eak eakss aare re likel likelyy ass assoc oc ociat iat iated ed with la larg rg rger er bi bird rd rds; s; th ther er erefo efo efore, re, tth he di differ ffer fferen en ence ce iin n win wing g llen en ength gth an and d bod bodyy m mas as asss bbet et etwe we ween en tthe he no nonsu nsu nsurviv rviv rvivin in ing g bi bird rd rdss aand nd th thee su surv rv rvivi ivi iving ng bird birdss wa wass si signi gni gnifica fica ficant. nt. Ta Tarsu rsu rsuss le leng ng ngth th ma mayy nnot ot be as stro strong ng ngly ly aasso sso ssocia cia ciate te ted dw with ith cchan han hanges ges in bo bod dy siz sizee aass th thee ooth th ther er ttra ra raits. its. EXTE EXTENS NS NSIO IO ION: N: Ev Evalu alu aluatin atin atingg Asso Associ ci ciate ate ated d Vari Variabl abl ables es 1. Using the data in Table 1, construct and label a scatter plot using a computer program or hand-graphing that illustrates the association between beak depth and wing length for the birds that survived the drought of 1977. Wing Lengt Length h as a Fu Functio nctio nction n of Beak Dept Depth h in SSurv urv urvivors ivors

2. Th Thee tr tren en end d liline ne is iillus llus llustr tr trated ated iin n th thee ggrap rap raph h aabo bo bove ve ve. 3. r2 = 0. 0.46 46 r = 00.68 .68 4. Based on these results, com comme me ment nt on the presence or absence of a relationship between beak depth and wing length in this population of medium ground finches. Stud Studen en ents ts nee need d onl onlyy ex expl pl plain ain tha thatt tther her heree aapp pp ppears ears tto o bbee a po positi siti sitive ve rel relatio atio ations ns nshi hi hip p be betw tw twee ee een n bbeak eak ddept ept epth h an and d wi wing ng len length gth in th thee ssur ur urviv viv viving ing gr grou ou oup p of m med ed edium ium ggrou rou round nd fin finch ch ches, es, and bi birds rds wit with h larg larger er be beaks aks ten tend d to als also o hhav av avee llong ong onger er win wings gs gs.. Note: Students may or may not provide the r2 value. For the IB curriculum, students are not expected to know how to interpret regression statistics, but they are expected to be able to add trend lines to scatter-plot data to show uncertainty in the apparent relationship between the x and y variables.

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5. Su Sugg gg ggest est a reason for the presence or absence of a relationship between beak depth and wing length in this population. Lar Large ge bbeeaks are lilikely kely as asso so socia cia ciated ted w with ith lar larger ger bi birds rds in ge gener ner neral; al; theref erefor or ore, e, bbeak eak ddep ep epth th and wi wing ng le leng ng ngth th fo forr the dro droug ug ught-s ht-s ht-surv urv urvivin ivin iving g bi birds rds are rrela ela elated ted ted.. No Notte: D Disc isc iscuss uss wi with th stu studen den dents ts tha thatt aass ss ssocia ocia ociatio tio tion n ((co co correl rrel rrelati ati ation) on) do does es no nott nec necess ess essari ari arily ly iimpl mpl mplyy ccaus aus ausati ati ation on on.. In oothe the therr w wo ords, la large rge rgerr be beaks aks aare re nnot ot ca causi usi using ng bird birdss tto o ...