1 / 17

Chordates

Chordates. The group of chordata includes all the vertebrates Fish, amphibians, reptiles, birds, and mammals. Common Characterisics. All chordata have the following characteristics: Notochord

wolfe
Download Presentation

Chordates

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chordates

  2. The group of chordata includes all the vertebrates • Fish, amphibians, reptiles, birds, and mammals

  3. Common Characterisics • All chordata have the following characteristics: • Notochord • A firm, flexible tube of tissue that is located on the dorsal side of the body (back-side of the body) • Hollow Nerve cord • Post anal tail

  4. Pharyngeal pouches • are small out-pockets of the anterior part of the digestive tract that become gills in aquatic chordates & jaws, inner ear, & tonsils in terrestrial chordates

  5. Fish • Fish were the first vertebrates to develop • The first fish were jawless • Fossil record shows jawless fish without paired fins appeared first about 550 million years ago

  6. Some common characteristics of Fish • Respire through gills • Body covered with protective scales & mucus layer to reduce friction when swimming • Cold-blooded • Move using fins • Eat plants, insects, and other fish • Lay eggs • Two-chambered heart

  7. Anatomy of a Fish

  8. Amphibians • Evolved from lobed fish • Adaptations: • Four limbs with claws on digits (toes) • Lungsinstead of gills • Both internal & external nares (nostrils) • Three chambered heart (two atria & one ventricle) Double loop blood circulation to lungs & rest of body cells

  9. Most with smooth, moist skin to take in dissolved oxygen • Some with oral glands to moisten food they eat • External fertilization

  10. Reptiles • Reptiles were 1st vertebrates to make a complete transition to life on land (more food & space) • Arose from ancestral reptile group called cotylosaurs(small, lizard like reptile) • Amniote (shelled) egg allowed reptiles to live & reproduce on land

  11. Dry, watertight skin covered by scales made of a protein called keratin to prevent desiccation (water loss) • Toes with claws to dig & climb

  12. Birds • Evolved from reptiles • Warm-blooded • Well adapted to marine, freshwater and terrestrial habitats

  13. Body covered with feathers made of protein called keratin • Thin, hollow bones • Some bones fused for extra strength • Forelimbs modified into wings for  flight • Two hind limbs with claws to support upright body

  14. Scales on legs • Toothless, horny beak • Additional air sacs  with lungs for more oxygen • Four chambered heart • Amniote egg with calcium carbonate shell

  15. Mammals • Four chambered heart • Mammary glands in females are modified sweat glands that make milk containing sugars, proteins, & fats to nourish young • Single jawbone • Specialized teeth for biting, cutting, & chewing • Highly developed brain (large cerebrum)

  16. Warm-blooded • Majority have fur • Have sweat glands for cooling • Fossil records show mammals arose from group of reptiles called therapsidsat the end of the Paleozoic era

More Related