1 / 13

Nonvertebrate Chordates, Fishes, and Amphibians

Nonvertebrate Chordates, Fishes, and Amphibians. What Is a Chordate?. Members of the phylum Chordata are called chordates .

obedience
Download Presentation

Nonvertebrate Chordates, Fishes, and Amphibians

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. Nonvertebrate Chordates, Fishes, and Amphibians

  2. What Is a Chordate? • Members of the phylum Chordata are called chordates. • A chordate is an animal that has, for at least some stage of its life, a dorsal, hollow nerve cord; a notochord; pharyngeal pouches; and a tail that extends beyond the anus.

  3. Characteristics of Chordates Notochord Muscle segments Hollow nerve cord Anus Tail Mouth Pharyngeal pouches

  4. Characteristics of Chordates • The notochord is a long supporting rod that runs through the body just below the nerve cord. • Pharyngeal pouches are paired structures in the throat (pharynx) region. • The tail can contain bone and muscle and is used for swimming by many aquatic species.

  5. What Is a Chordate? Most Chordates Are Vertebrates • About 96 percent of all chordate species are vertebrates. • Most vertebrates have a vertebral column, or backbone. • In vertebrates, the dorsal, hollow nerve cord is called the spinal cord.

  6. What Is a Chordate? • As a vertebrate embryo develops, the front end of the spinal cord grows into a brain. • The backbone is made of individual segments called vertebrae. • In addition to support, vertebrae enclose and protect the spinal cord.

  7. Phylogeny of Chordates Mammals Birds Reptiles Amphibians Bony fishes Sharks & their relatives Jawless fishes Nonvertebrate chordates Invertebrate ancestor

  8. Nonvertebrate Chordates • The two groups of nonvertebrate chordates are tunicates and lancelets. • Similarities in anatomy and embryological development indicate that vertebrates and nonvertebrate chordates evolved from a common ancestor. • Both tunicates and lancelets are soft-bodied marine organisms.

  9. Tunicates (Larva) Tail • The larval form of filter-feeding tunicates have all of the chordate characteristics. Hollow nerve cord Waste- eliminating organ Notochord Mouth Intestine Stomach Pharynx with gill slits Heart Larva

  10. Tunicates (Adult) Siphon to mouth Pharynx with gill slits Siphon from anus Anus Tunic Intestine Reproductive organs Heart Stomach Adult

  11. Lancelets • Lancelets are small, fishlike creatures that live on the ocean bottom. Hollow nerve cord Notochord Segmented muscles Mouth Tail Pharynx with gill slits Anus Intestine Reproductiveorgans

  12. Lancelets • An adult lancelet has a definite head region that contains a mouth. • As water passes through the pharynx, a sticky mucus catches food particles. • The lancelet swallows the mucus into the digestive tract.

  13. Lancelets • Lancelets use the pharynx for gas exchange. • Lancelets are thin enough to exchange gases through their body surface. • Lancelets have a closed circulatory system and do not have a true heart.

More Related