1 / 27

Chapter 34

Chapter 34. Vertebrates. Vertebrates. These are a subphylum of the phylum Chordata. They are deuterostomes. Chordates. Bilaterally symmetrical. They are deuterostomes. Have a notochord. Derived Characters of Chordates. 4 key characters of chordates: 1. A notochord

salvador-gilmore
Download Presentation

Chapter 34

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. Chapter 34 Vertebrates

  2. Vertebrates • These are a subphylum of the phylum Chordata. • They are deuterostomes

  3. Chordates • Bilaterally symmetrical. • They are deuterostomes. • Have a notochord.

  4. Derived Characters of Chordates • 4 key characters of chordates: • 1. A notochord • 2. A dorsal, hollow nerve cord • 3. Pharyngeal slits or clefts • 4. A muscular, post-anal tail

  5. 1. Notochord • A longitudinal, flexible rod between the digestive tube and the nerve cord. • It is fluid filled and provides support for the animal.

  6. 1. Notochord • Larvae and adults that retain it: • The muscles can work against it. • In animals that develop a skeleton, the remnants of the notochord are disks.

  7. 2. Dorsal Hollow Nerve Cord • Develops from a plate of ectoderm. • It rolls into a tube dorsal to the notochord. • Dorsal hollow nerve cords are unique to chordates. • The nerve cord develops into a CNS.

  8. 3. Pharyngeal Slits or Clefts • The region just posterior to the mouth is the pharynx. • All chordates have a series of pouches separated by grooves that allow water to pass in and out without having to go through the entire digestive tube.

  9. 3. Pharyngeal Slits or Clefts

  10. 4. Muscular, Post-Anal Tail • Many species of chordates lose their tail during embryonic development. • For aquatic animals that retain it, it provides a propelling force for the animal.

  11. Craniates • Craniates are cordates with a head. • They have two clusters of Hox genes. • They have a neural crest.

  12. Neural Crest • These are the cells that appear as the neural tube closes. • These cells get dispersed throughout the body. • They give rise to many structures: • Teeth, bones and cartilage of the skull, the dermis of the face, neurons, sensory organs

  13. Craniates • In aquatic craniates, the pharyngeal clefts evolved into gill slits. • In terrestrial craniates, the slits develop into important parts of the inner ear and neck.

  14. Vertebrates • Dlx gene duplication gave rise to increased nervous system complexity, more extensive skull and a backbone with vertebrae. • The vertebrae enclosed the spinal cord. • Dorsal, ventral, and anal fins stiffened with fin rays enhanced swimming.

  15. Gnathostomes • Vertebrates with jaws.

  16. Derived Characters • Jaws • Duplication of Hox genes: • Gave rise to larger brains, enhancing smell and vision. • Aquatic gnathostomes have a lateral line.

  17. Tetrapods • Animals with four feet derived from the lobe fins. • Made the move to land. • Their body changed to allow for walking.

  18. Amniotes • Tetrapods (mammals and reptiles, including birds) with adaptations for land. • Amniotic egg. • Contains extraembryonic membranes that protect the embryo. • Function in gas exchange, waste storage, and nutrient exchange.

  19. The Amnion • Bathes the embryo and acts as a shock absorber. • Eggs contain either a calcareous shell or a leathery shell to protect against dehydration. • Expanded habitat choices.

  20. Amniotes • Also acquired less permeable skin, a ribcage to ventilate the lungs, and a more upright or elevated stance.

  21. Derived Characters of Mammals • Mammary glands • Body hair • Live young • Endothermic • Differentiation of teeth

  22. Monotremes • Platypus, ant eaters. • Found only in Australia and New Guinea. • Lay eggs that hatch. • The mom secrets milk from a gland in the belly. • No nipples, the hatchlings suck milk from the mother’s fur.

  23. Marsupials • Opossum, kangaroos, and koalas. • High metabolic rate, nipples, live young. • Embryo partially develops in the uterus. • When born, it completes its development in the mother’s pouch.

  24. Eutherians • These are the placental mammals. • High metabolic rate, nipples, live young. • Longer period of gestation. • Embryonic development is completed within the uterus.

More Related