Tulerpeton (~362 mya) Acanthostega (-365 mya) Tiktaalik (~375 mya) Eusthenopteron (~385 mya) Distal elements Fin rays Ulna and radius Humerus Figure 22.4 Transitional Features during the Evolution of the Tetrapod Limb. Fossil species similar to today's lungfish and tetrapods have fin and limb bones that are transitional features. Eusthenopteron was aquatic; Tulerpeton was semi-aquatic (mya million years ago). SOURCE: Based on E. B. Daeschler et al. 2006. A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature 440: 757-763, Fig. 6; P. E. Ahlberg and J. A. Clack. 2006. A firm step from water to land. Nature 440: 747-749, Fig. 1; N. H. Shubin et al. 2006. The pectoral fin of Tiktaalik roseae and the origin of the tetrapod limb. Nature 440: 764-771, Fig. 4; M. Hildebrand and G. Goslow. 2001. Analysis of vertebrate structures, 5th ed. John Wiley and Sons, Inc.

What does the image say about the bones in the fins of fish (on the left side) when compared to the bones in their tetrapod ancestors (on the right side)? They are homologous structures Nothing can be concluded about the relationship They are analogous structures The structures are unrelated

Amniotes are descended most closely from which of the following groups O reptiliomorphs O lepospondyls O batrachomorphs sauropodomorphs Vertebrates possess all the following synapomorphies except which? * O bone O ventral nerve cord O vertebrae O expansion of anterior nerve cord cranium

A Body kite-ike in shape (if viewed trom the top). 332 What does the abbreviation mya stand for? B. Body not kite-like in shape (if viewed from the top). Go to statern 2 0T How old is the earth? 2. A Pelvic fin absent and nose saw-like Family Pristiophoridas B. Pelvic fin present Go to staterment 3 3 A Six gill slits present Family Hexanchidae B. Five gill slits present Go to statement 4 4 A Only one dorsal fin present Family Scyliorhinidae B. Two dorsal fins present.. Go to statement 5 5 A. Mouth at front of head rather than back on ventral side of head Family Rhinocodontidae B. Mouth back on ventral side of head Go to statement 6 6 A. Head expanded on side with eyes at end of expansion. Family Sphymidae B. Head not expanded Go to statement 7 7 A. Top half of caudal fin exactly same size and shape as bottom half. .Family Isuridae B. Top half of caudal fin different in size and shape than Go to statement 8 bottom half. 8 A. First dorsal fin very long, almost half total length of body..…

What is the possible reason why some cnidarians had evolved to a stony skeleton? plz include citationsss

Sharks Ray-finned fiah Rodents & rabbits Crocodiles Dinosaurs & birds Primates Hair Two post-orbital fenestrae Amniotic egg Four limbs BONY SKELETON Hypothesis 1 Vertebrae Rodents & rabbits Crocodiles Sharks BONY SKELETON Primates Hair Two post-orbital fenestrae Amniotic egg Hypothesis 2 Four limbs Which tree is the most parsimonious? BONY SKELETON Vertebrae O tree #2 O tree #1 Amphibians Ray-finned fish Amphibians Dinosaurs & birds

Extast Cyclostomes, whichincludes has fishesnd Lampreys, are theo dest lineage of vertebrates, which chaachteran co) difforentlates extat Cycbstre from extant cartildaginaus Aish (chandraichlyns)? Lyclostomes lack Jaws Cycbstomes haye cartlaginous, skeletons Darsal and ventral fAns absent from Cyclostones Cyclostones lack a Vertebrad Colum Cyclostames have mineralization of Skelehms

Hoplophoneus primaevus Skeleton vs Siberian Tiger Skeleton vs Smilodon Necator SkeltonCompare and contrast the appearance of specific bones in the skeleton.  Compare the skeleton of the extinct creatures with the extant creature, and with themselves.  How might the variation in anatomy link to the likely function? Compare species' skeletal anatomy based on life history (aquatic vs terrestrial). What are other interesting factors noted in the skeletons?

This West Indian manatee (Trichechus manatus) is an aquaticmammal. Like amphibians and reptiles, mammals are tetrapods (vertebrates with four limbs). Explain why manatees areconsidered tetrapods even though they lack hind limbs, andsuggest traits that manatees likely share with leopards andother mammals (see Figure 26.12b). Discuss how early members of the manatee lineage might have differed from today’smanatees.

Consider the cladogram representing most of the major classes of animals. Consider the point A in the cladogram. What characteristic(s) might be used to separate fish from the other animals following in the cladogram? hale symmetnical ancestor O Endoskeleton O Non-terrestrial O Four legs or supports O The presence of scales