Phylum Chordata Chordate Characteristics - Home - … Chordata- vertebrates Animal phylogeny based on sequencing of SSU-rRNA Phylum Chordata • Distinguishing Features – 1. Pharyngeal
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Chordata- vertebratesAnimal phylogeny based on sequencing of SSU-rRNA
Counter-current gas exchange 7 Basic Requirements 7 Basic Requirements of Animal Lifeof Animal Life
1. Gas exchange2. Nutrition3. Distribution and transport4. Disposal of cellular wastes5. Internal water and salt balance6. Reproduction and development7. Support and movement
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Vertebrate Invasion Onto Land• Demands of terrestrial life:
– How to move on land?– How to exchange gases?– How to prevent desiccation?– How to reproduce and develop?
A coelocanth (Latimeria), the only extant lobe-finned genus
Amphibians: the first tetrapods• 3 Orders
– Urodela - salamanders and newts– Anura - frogs and toads– Apoda - caecilians (legless amphibs)
• General Features– Locomotion– Feeding– Gas exchange– Osmoregulation– Circulation– Reproduction and development
• Metamorphosis– Hearing and voice
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Figure 34.18 “Dual life” of a frog (Rana temporaria)
Modern Reptiles: Adaptations• Desiccation resistant
Avian Characteristics1. Endothermic Homeotherms2. Feathers3. Hollow bones4. Skeletal fusion5. Loss of tail6. Beak7. Gizzard8. Digestive and urinary changes9. Respiratory changes10. Circulatory changes 11. Reproductive changes12. Parental care
Form fits function: the avian wind and feather A bald eagle in flight
Mammalian Characteristics1. Endothermic Homeotherms2. Hair or fur covering3. Mammary glands4. Single boned jaw5. Heterodont dentition6. Rearrangement of pectoral and
Australian monotremes and marsupials: echidna (top left), marsupial mouse (lower left), sugar glider (right) Mammalian Reproductive Strategies:
• Monotremes: Echidna and Duck-billed platypus
• Marsupials: premature delivery
• Placental Mammals: – internal development– Reuse of extra-
embryonic membranes
PlacentaEvolutionary convergence of marsupial and eutherian
(placental) mammals
• Move from trees onto ground
• Concomitant morphological changes
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Hominid Evolution• Lucy ~ 3.5 mya
7 Basic Requirements 7 Basic Requirements of Animal Lifeof Animal Life
1. Gas exchange2. Nutrition3. Distribution and transport4. Disposal of cellular wastes5. Internal water and salt balance6. Reproduction and development7. Support and movement