11:1;: Evidence for Evolution RM 6

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1 RM 6 Statin 1: Fssils Fssils are preserved evidence f prehistric life. Fssils are either bdy fssils, like bnes, teeth, r shells, r trace fssils, like ftprints r burrws. Scientists study fssils t understand the evlutinary histry f life. Since the shape f an anial's teeth depends n what it eats, studying fssil teeth can tell yu abut a prehistric anial's fd and habitat. Herbivres that eat grasses have a high crwn abve the rt f the tth. This adaptatin is an advantage because the teeth f grass-eating herbivres cnstantly get wrn dwn by abrasive silica particles in the cells f grass leaves. Herbivres that eat the relatively sft leaves f trees and shrubs have a lw crwn abve the rt. Lking at the pattern f change in hrse teeth ver the past 50 illin years, palentlgists have hypthesized that tday's grassland herds f zebra and ther hrses evlved fr frest-dwelling anials that ate the leaves f trees r shrubs. Ouestins: 1. D yu think the pattern f change shwn by the hrse teeth supprts this hypthesis? Why r why nt? 2. Hw wuld yu test this hypthesis? 11:1;: TExASElXr.Al1ONA TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 163

2 g. I'\.:) -l en c 2:j :z»(j) :z :-<» r r :IJ (j) :r: -l en :IJ (J) :IJ <!=J fl..... il.li,'. I c If i:,![. Ir'!. ;.. \, I " \, > JJ :s: :::. <J)Q. (1) (') ::l (1) _. :J C 0 CD -:.. -t: _. ::J Figure 1. Hyractheriu (apprx. 52 illin years ld) Figure 2. Meshippus (apprx illin years ld) Figure 3. Merychippus 15 illin years ld) (apprx. Figure 4. Equus (apprx. 5 illin years ld t present) --A. OJ (j1

3 RM7 Statin 2: Bigegraphy Bigegraphy is the study f species distributin patterns acrss gegraphical areas. With the intrductin f new technlgies, bigegraphy nw als includes the study f gene distributin patterns acrss gegraphical regins. Sickle cells are abnrally shaped red bld cells caused by a recessive utant gene that cdes fr an abnral fr f the heglbin prtein. Peple wh inherit a cpy f the utated gene fr each parent develp sickle cell disease, which causes fatigue, pain, strke, rgan daage, and ften death befre adulthd. Peple wh nly have ne cpy r n cpies f the utant heglbin gene are generally healthy..."..".'... '::'.: '.' :': <.' ".:.:: t : '. '... Percent f Ppulatin With the Sickle-Cell Allele _14+ " !8-10 1l Since the disease caused by the hzygus cnditin is deadly, dctrs wrking in Africa were puzzled by the abnrally high rate f the utant gene fund there cpared t the rest f the wrld. (g t next card) TAli. TEXASEDUcA110NAGrnCY 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 167

4 RM 7 cntinued Statin 2: Bigegraphy (cntinued) Wrking in the 1950s, British dctr Anthny Allisn nticed a pattern: ppulatins with elevated rates f the utant sickle-cell gene are lcated in the sae gegraphical areas as the rganis that causes severe alaria. Malaria is an infectius disease caused by a parasite transitted by squits. Severe alaria ften causes ca and death. Dr. Allisn hypthesized that the evlutin f this gene ust prvide an advantage in regins where alaria is present. _ Gegraphical Range f Malaria (st severe frs) : J.\ - Questins: 1. D yu think the infratin and ap data supprt Allisn's hypthesis? Why r why nt? 2. Hw wuld yu test this hypthesis? 1111: TEXASEDcAllONAtiNCY 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 169

5 I Evidence fr Evlutin RM 8 Statin 3: Mlecular Hlgies In bilgy, a hlgy is defined as a siilar trait shared ang rganiss that evlved fr a cn ancestr. The trait ay have changed ver tie depending n whether the variatin prvided an advantage fr survival. Scientists lk fr hlgies as part f the evidence fr evlutin. With careful study, scientists can supprt r reject a hypthesis abut a cn rigin. Scientists have discvered a prtein fund in the cells f st eukarytic rganiss called cytchre c. It is a critical part f cellular energy transfer and thus necessary fr life. This akes cytchre c an ideal lecule t study evlutinary relatinships. The re clsely related tw species are, the fewer the differences in the ain acid sequence. The re distantly related tw species are, the larger the nuber f differences in the ain acid sequence. Use the table "Ain Acid Sequences f Cytchre c in Fur Organiss" t analyze the evlutinary relatinship between three rganiss f yur chice. T get started, chse tw f yur rganiss and cunt the nuber f ain acid differences. Recrd yur data in yur ntebks n a data table siilar t this ne: Nuber f ain acid differences Organis A vs. Organis B Organis A vs. Organis C Nte: Ain acid sequences that are identical ang all fur rganiss are illustrated by a dash in the table. Questins: 1. Which rganiss did yu chse t analyze? 2. Based n yur analysis, hypthesize which tw rganiss are re clsely related. 3. Hw wuld yu further test yur hypthesis? Tfll TEXASEIlX'.A11ONftO' 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 171

6 RM 8 cntinued Statin 3: Mlecular Hlgies (cntinued) Ain Acid Sequences f Cytchre c in Fur Organiss "':.$ga(poj: l1u lail ll \!i'a:ii7""''''''a109l;lu!llilh'5c enf(oq &"V%eaC:ll 1 x x x Ala 57 Thr Thr Thr Ser 2 X x x Ser 58 Asp Ala Asp Ala 3 x x x Phe x x x Ser x x x Glu x x x Ala x x x Pr x x x Pr 64 Glv Glv Glv Ala lie lie lie Val 10 Asp Asp Asp Asn 66 Thr lie Thr Glu 11 Val Val Val Pr Glu Glu Glu Asp 68 Glv Glv Glv Glu 13 Lvs Lvs Lvs Ala 69 Glu Glu Glu Glu Asp Asp Asp Asn 15 Lvs Lvs Lvs Ala Met Met Met Tvr Glu Glu Glu Asp 19 Val lie Val Lvs Gin Met Gin Thr "I , II UIU Glu Glu LC;U Ala Ser Ala Ala Val Val eve Val Glu Glu Glu Asp Lvs Lvs Lvs Ala Glv Glv Glv Ala Lvs Lvs Lvs Glv 89 lie lie lie Val Ala Val Ala Pr 36 Thr Thr Val Gin lie lie lie Leu Lvs Lvs Lvs Pr 41 Asn His Tvr His 97 Glv Glu Glv Gin Glu Glu Glu Asp 43 lie Leu Leu Leu 99 Ara Ara Arc Arc 44 Phe Phe lie Phe 100 Ala Ala Gin Ala Lvs Lvs Lvs Gin Thr Thr Thr Ser Gin Gin Gin Thr Ala Ala Ala Thr Pr Pr Ala Ala 108 Lvs Lvs Ser Lvs Phe Tvr Phe Tvr 110 Thr Thr eve Thr 55 Thr Ser Ser Ser 111 Asn Asn Ser Ser Glu Glu Lvs Ser TE/f TEXASElXr.ATIONAliNCY 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 173

7 RM 9 Statin 4: Anatical Hlgies In bilgy, a hlgy is defined as a siilar trait shared ang rganiss that evlved fr a cn ancestr. The trait ay have changed ver tie depending n whether the variatin prvides an advantage fr survival. Scientists lk fr hlgies as part f the evidence fr evlutin. With careful study, scientists can supprt r reject a hypthesis abut a cn rigin. Scientists wh have cpared the skulls, teeth, and tusks f different elephant fssils hypthesize that the tusks f dern elephants evlved fr teeth. <->:» /' J, '..> /A\\ The skull f Meritheriu, an elephant that lived abut 55 illin years ag The skull f Gphtheriu, an elephant that lived abut 20 illin years ag The skull f the ath, Mauthus, an Ice Age relative f Hving elephants Questins: 1. D yu think the illustratins supprt this hypthesis? Why r why nt? 2. Hw wuld yu test this hypthesis? Nte: artist renderin nt t scale TE1i TEXASEDcATIONAGENCY 2010 TEXAS EDUCATION AGENCY. ALL RIGHTS RESERVED. 175