Verterbrates online Worksheet Tetrapod Evolution 1. Great Transformations Interactive: Exploring Transitional Fossils A. What is the reasoning behind the expectation that transitional fossils must exist? B. Based on limb structure, explain why we think that Coelacanth is the ancestor of tetrapods. C. What is the importance of the rib cage for life on land, compared to life in water? What features are different? D. How did the number of digits change during tetrapod evolution? 2. Tiktaalik A. What three things do researchers need to address in order to find transitional fossils that demonstrate how a particular animal evolved? B. Why did Shubin collect tropical fossils in Pennsylvania? C. What anatomical features did Tiktaalik possess that were both fish-like and tetrapod-like? D. Why is Tiktaalik important? E. Why do many of the transitional fossils between fish and tetrapods have flat heads? Ancient Fish 1. Why is the coelacanth called a "living fossil"? 2. Approximately when was the coelacanth thought to have gone “extinct”? When was it rediscovered, and by whom? 3. What features make the coelacanth important in the evolution of land vertebrates? Fish 1. What is a significant challenge to living in water compared to land? 2. Starfish live in water too. How do we know starfish are not actually “fish?” Is a jellyfish a “fish?” Why or why not? 3. What two structures assist fish in swimming? 4. Why is the swim bladder an important example of “function follows form”? 5. Which was the earliest group of bony fishes to become widespread? 6. Why is the evolution of the jaw so important to the subsequent diversification of fish? 7. How is fish fertilization different from human fertilization? Amphibians 1. What does the term “amphibian” mean? 2. Although terrestrial, why do frogs need to live near water? 3. What are the three stages of the frog’s life cycle? 4. Why is the jelly-like coat beneficial to the frog eggs? 5. In which ways is the larval stage of the developing frog like a fish? 6. How would the embryonic development of a frog be similar or different from a human? How about a chicken or a reptile? 7. Why is it important that the frog evolved to have eyelids? 8. What are two anatomical features that relates to an aquatic lifestyle? 9. How does the frog undergo respiration? How does this relate to their environment? 10. Into what structure does the digestive, excretory & reproductive systems empty their products in a frog? Reptiles 1. Video 1 A. Reptiles are categorized into what major groups? B. What feature(s) have reptiles evolved that make them less dependent on water compared to amphibians? C. Name two roles scales serve in snakes and tortoises. D. What two adaptations allow crocodiles to swim and breath under water? E. Which class is more diverse? Reptilia or Mammalia? F. Reptiles are “cold blooded” or ectothermic. Explain why this does not necessarily mean their blood is cold on a hot summer day. G. What is the advantage of being cold blooded? 2. Video 2 A. These terrestrial vertebrates were the first to do what? B. Reptilian amniotic eggs are also produced by __________ and __________ C. What does the term poikilothermic mean? D. Amphicoelias was 270,000lbs. How many of YOU is that? Show how you calculate the answer. Birds: 1. Why are the bones hollow in birds? 2. Why do birds need very efficient lungs? 3. What is the function of the crop? 4. What is the evidence that birds evolved from dinosaurs? Explain your answer… 5. Where did feathers come from evolutionary wise?? Mammals: 1. Video 1 1. Describe the characteristics that all mammals have in common. 2. Which characteristic points at mammals having evolved from reptiles? 3. What are the maing groups within the mammalian lineage? 4. What are the functions of the sebaceous and sweat glands? 5. How are the teeth of mammals different from that of a reptile? 6. What does it for an animal to be endothermic? 2. Video 2 7. What is the main basis for separating mammals into three major groups? 8. Describe the basic characteristics of the 3 major mammalian groups.