Great Transitions Interactive

GREAT TRANSITIONS INTERACTIVE INTRODUCTION 1. Tetrapods are YVESTODYANES birds rcomes Examples of tetrapods include mammals and amphibians 2. Tetrapods first appear in the fossil record 365 million years ago. 3. Charles Darwin predicted that tetrapods evolved from fisn What observation leads to that hypothesis? Darwin observed that fun fassius appeared in rocks that are more than 500 million yrs old Meaning, fisn predare tetrapods 4. What evidence would you expect to find to support that hypothesis? What age rocks would you look in and why? 1011000d fossils appeared in rocks from aus million yrs ago. Su so the transition from water (tish) to land occured Defort inen I would loon Gilis or Lungs? ransitional I for a todon 360 10 300 10 dare whether fish came befert tetrapods 5. Fish use Gills to breathe underwater. (However, many species of lobe-finned fishes that evolved during the Devonian period also had, Lunge 6. In fossils, what anatomical evidence indicates that gills were present? 10oulder poner and shuns 7. Many transitional species had gills which means that they lived in 9000110 1ncurions 8. Lungs allow an animal to breathe Why did this adaptation evolve? The ability to breathe air evolved as an adaptation to life in water poor in Oxygen rever or as suppicmentory brearning for shallow water 9. Tetrapods use ungs to breathe. Do any modern tetrapods have gills? Explain. ves, for examtpitro or omir ampnicians have gius as larvat since their birth iolation is aquatic) but most lost meir gils as adum The Ribcage 10. Why is a sturdy ribcage important for tetrapods? Istuigy Riocage is needed in order to support the weignt Tht of ine body out of water and it prevens int jungr from Collapsing. Humerus (Limbs) 11. What is homology? To what are fins homologous? Homology is the shared ancestry blwsimilar structures Fol, Exampit fins are nomelogous to limbs. 12. Why are lobe-finned fish thought to be the closest relatives to tetrapods? It is partly because the fisn's front and back pairs of fins are supporrld of ar int post by a single bone similar to the numerw and femur. Digits 13. Most modern tetrapods have five digits on front limbs and digits on back limbs, although some species have fewer. How does this number compare to the number of digits on the limbs of transitional fossil forms? with transitional species. the # of digits during the tetrapod eveivrion changed from 8, 107 in the back is unknown in the front), in total, and then w in the back and s in the front. The croivrionary paterm snows the # of digits decrease probably bic of lack of usage Head and Neck or a change in terrain 14. Why do many of the transitional fossils between fish and tetrapods have flat heads? During the transition from water to land, the nead became flat / the eyes locared on the top, maybe as an adaptation to living in the shallow water environment. 15. How did the anatomy of the shoulder and head change during tetrapod evolution? During tetrapod evolution, the head shoulder bones Jeperated from meshvil p the skull was abic to more independently from the shoulder & the rest of the body COMPARING FOSSIL FORMS 16. Panderiinthus and Eurhen optellare fossil species have characteristics unique to fish as well as characteristics found in fish and tetrapods. Describe the characteristics of lobe-finned fish that are similar to those of tetrapods. int lopt-finned fish nad lungs and a numerus which are retrapod features the ability to brearne air was Laitol mainly a retrapod feature as waw the numerw, however both appear in lope-finned fish 17. Which lobe-finned fish is alive today? Coelacanth 18. Acanthostega and icythyostega have been called fish-like tetrapods. Explain why they are described as such and describe the environment in which they probably lived. The Acaninostead and kyrnasiiga both nave gilu and limited movement of strengen in their times (couldn't support body wright to predominantly ve on land) However, their limb structures resemble those of modern retrapods tren though their Fish-line teatures meant ingy had a mort aquatic lifestVic 19. Why is Tiktaalik such an important transitional fossil? The Tiktaalik is not labeled as a retra pod-line fish ora fishing tetrapod but rather as the bridge biw the two groups As it has retrapod features, such as strong back fins to support its body weight and fused Dip bond that creared a "Thuray structure the fismline tearvin navde a flat nead, which 20. Pellerpes and fuierpeton neipe it live in inanew warer are early tetrapods that do not have features unique to fish. Describe how these two species differ anatomically and what that means about where they each lived. The twitsperon's limbs are more developed than a other fossil species is shoulder bones are more davanced thon the Acanthostega meaning it spentier time in water but was still considered a marint species. wncreas, ine prorepes nod limbs and feet made for a terrestrial plain, and was not a predominantly aquant species.