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Unit 9 Chordates. Ch. 33 Comparing Chordates. The Chordate Family Tree. The chordate family tree has its roots in ancestors that vertebrates share with tunicates & lancelets. The Chordate Family Tree. Evolutionary Trends in Vertebrates.
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Unit 9 Chordates Ch. 33 Comparing Chordates
The Chordate Family Tree • The chordate family tree has its roots in ancestors that vertebrates share with tunicates & lancelets
Evolutionary Trends in Vertebrates • Over the course of evolution, the appearance of new adaptations (jaws & paired appendages) has launched adaptive radiations in chordate groups • Adaptive radiation - the rapid diversification of species as they adapt to new conditions
Evolutionary Trends in Vertebrates • A rapid increase in the # & diversity of land vertebrates followed the evolution of 4 limbs
Body Temperature & Homeostasis • The control of body temperature is important for maintaining homeostasis in vertebrates, particularly in habitats where temperature varies widely with time of day & with season
Body Temperature & Homeostasis • The internal control of body temperature allows emperor penguins to live in cold Antarctic climates, where their feathers act as insulation
Body Temperature & Homeostasis • Ectotherm - the body temperature is determined by the temperature of the environ.; the animals pick up heat from, or lose heat to, their environ. • Most reptiles, fishes, & amphibians are ectotherms
Body Temperature & Homeostasis • Endotherm - an animal whose body temp. is controlled from within; they can generate & retain heat inside their bodies • Birds & mammals are endotherms
Form & Function in Chordates • Feeding: • The blunt, broad jaws & numerous teeth of crocodiles help them catch large prey, even in thick vegetation
Form & Function in Chordates • Feeding: • The digestive system of vertebrates have organs that are well adapted for different feeding habits
Form & Function in Chordates • Respiration: • As a general rule, aquatic chordates (tunicates, fishes, & amphibian larvae) use gills for respiration • Land vertebrates (adult amphibians, reptiles, birds, & mammals) use lungs
Form & Function in Chordates • Circulation: • During chordate evolution, the heart developed chambers & partitions that help separate oxygen-rich & oxygen-poor blood traveling in the circulatory system • The heart of fishes have 2 chambers, amphibians & most reptiles have 3 chambers, & crocodilians, birds, & mammals have 4 chambers
Form & Function in Chordates • Response: • Nonvertebrate chordates have a simple nervous system with a mass of nerve cells that form a brain • Vertebrates have a more complex brain with distinct regions, each with a different function
Form & Function in Chordates • Movement: • The skeletal & muscular systems support a vertebrate’s body & make it possible to control movement • Muscles & ligaments attach the appendages to the backbone & help control movement
Form & Function in Chordates • Reproduction: • Almost all chordates reproduce sexually • Vertebrate evolution shows a trend from external to internal fertilization