OCEA 80A – Life in the Sea Spring 2013 Worksheet for fishes, seabirds, and marine reptiles SECTION ONE – MARINE FISHES The fishes and marine mammals belong to the Phylum Chordata. To which Subphylum do they belong? What makes animals in this subphylum different from the invertebrate chordates? Which fin(s) would you expect to see in a jawless fish such as a hagfish? Which fin(s) do they lack? How does this affect their ability to swim? Describe how a jawless fish such as a hagfish can take a bite out of its prey. What are the advantages of an entirely cartilaginous skeleton, compared to a skeleton that is primarily bone? What group of fishes has ampullae of Lorenzini? What does the fish do with these structures? How does a fish's lateral line system work? What kind of information does it collect? Describe 3 anatomical adaptations for fast swimming would you see in a tuna. How does each of these adaptations contribute to a tuna's ability to swim at high speeds for long periods of time? Define the following terms: mouth brooding gill arch demersal ovoviviparous oviparous viviparous swim bladder countercurrent exchange What is the evolutionary significance of the coelacanth? Explain the evidence for your answer. Fishes evolved in the sea, while other vertebrate groups (birds, reptiles, mammals) evolved from land ancestors and returned to the sea. Compare and contrast marine fishes with other marine vertebrates, addressing the following: method of locomotion, how the animal obtains oxygen, sensory systems, thermoregulation. Hint: your textbook will give you a lot of insight about these matters. SECTION TWO – MARINE REPTILES Define the following terms: tetrapod vertebrate poikilotherm fibropapilloma tumor behavioral thermoregulation What are the three main challenges to terrestrial life that were faced by the first tetrapod vertebrates? Which animal is the likely evolutionary ancestor to the tetrapod vertebrates? What is the evidence for this? Which marine reptile is the most likely to make long migrations at sea and return to the beach where it was born? To which group of land snakes are sea snakes most closely related? What is the significance of this relationship, from the sea snake's point of view? Which marine reptiles are herbivores? Which are carnivores? Which are most likely to attack humans? SECTION THREE – SEABIRDS What are the four main orders of seabirds? What birds are in each order? What are the major characteristics of each order? Most birds have hollow bones. Why are hollow bones advantageous for these birds? Which seabirds have solid bones? How do these particular birds get away with having solid bones? A seabird that lacks nostrils most likely feeds in what way? What is "central place foraging"? What is the central place to which the foraging birds return? What are some challenges to life at sea, for birds? For each challenge you come up with, describe an adaptation that allows seabirds to overcome it. Explain why large body size is advantageous in seabirds. What are the life history traits that characterize seabirds? How do these traits affect seabird populations? Do seabird populations grow quickly? Why or why not? In what ways are seabirds threatened at sea? What threats do they face on land? .