Aecoi"din(s to the i'esult,; of the stiidy, for the Group 3 p()t.%. whLII ivas the iiveraiye plant Inas% in g/plant, and whilt w'i% the cqi'LratFe (ri-ain yield in g ot gi-ain/plaiit'? aTreri2ge plant Inass averaoe grain yield ACT-74H 41 GO ON TO THE NEXT PAGE. 40000000004 Passage 111 Student 2 Their both haviniF wings 1% a good indicatioii that bats and birds are more closely ielated to each other than either is to other vertebrates without wings. The MRCA of all vertebrates with wings must have had wings. As ¥hown in Figure 2, the MRCA ot bats and birds. represented at Node Z, evolved to give risc to all winged vertebrates. Both bats and birds have wings used for flight. Two students pi'esent opposing views about whether the pres- ellce of the wings is an indication that bats and birds are more clo,%ely related to each other thali either is to other vertebrates without wings, such as humans. Included in each student's presentation is a cladogram, a diagram that show8 the evolutionary history of several species. A clado- gram organizes species into clades based on descent from a commoii ancestor. A clade is a set of related species and their iiiost recent common ancestor (MRCA). Point W humans S114dent I Although both have wings, bats and birds are not moTe closely related to each other than either is to other verte- brates without wings. Although the wings of bats and birds evolved in response to similar selective forces, they evolved independently of one another, as shown in Figure l. The wings ol birds evolved at Point A, whereas the wings of bats evolved at Point B. Point X bats Nodey Node Z Point A Figure 2 birds Evidence that the bone structure of a bat win(F is simi- lar to that of a hutnan hand doe.8 not indicate that bats and human8 are clo.sely related beciiuse bats. bii'd.%, cind human, all have a similar forelimb bone slructure. Humans and bats are both mammals. but the Inammalian characteri8tics of humans and of bats evolved at Points W and X. respectively. Point B bats Node C Node D humans Fi(rure I
