End Show Slide 1 of 25 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 25 Copyright Pearson Prentice Hall 30-1 The Chordates

End Show 30-1 The Chordates Slide 3 of 25 Copyright Pearson Prentice Hall What Is a Chordate? What characteristics do all chordates share?

End Show 30-1 The Chordates Slide 4 of 25 Copyright Pearson Prentice Hall 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. What Is a Chordate?

End Show 30-1 The Chordates Slide 5 of 25 Copyright Pearson Prentice Hall Characteristics of Chordates Muscle segments Mouth Pharyngeal pouches Anus Tail What Is a Chordate? Hollow nerve cord Notochord

End Show 30-1 The Chordates Slide 6 of 25 Copyright Pearson Prentice Hall The notochord is a long supporting rod that runs through the body just below the nerve cord. What Is a Chordate? Notochord

End Show 30-1 The Chordates Slide 7 of 25 Copyright Pearson Prentice Hall Pharyngeal pouches are paired structures in the throat (pharynx) region. Pharyngeal pouches What Is a Chordate?

End Show 30-1 The Chordates Slide 8 of 25 Copyright Pearson Prentice Hall The tail can contain bone and muscle and is used for swimming by many aquatic species. Tail What Is a Chordate?

End Show 30-1 The Chordates Slide 9 of 25 Copyright Pearson Prentice Hall 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. What Is a Chordate?

End Show 30-1 The Chordates Slide 10 of 25 Copyright Pearson Prentice Hall 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. What Is a Chordate?

End Show 30-1 The Chordates Slide 11 of 25 Copyright Pearson Prentice Hall Phylogeny of Chordates Sharks & their relatives Bony fishes Amphibians Reptiles Birds Mammals Invertebrate ancestor Jawless fishes Nonvertebrate chordates What Is a Chordate?

End Show 30-1 The Chordates Slide 12 of 25 Copyright Pearson Prentice Hall Nonvertebrate Chordates What are the two groups of nonvertebrate chordates?

End Show 30-1 The Chordates Slide 13 of 25 Copyright Pearson Prentice Hall Nonvertebrate Chordates The two groups of nonvertebrate chordates are tunicates and lancelets. Nonvertebrate Chordates

End Show 30-1 The Chordates Slide 14 of 25 Copyright Pearson Prentice Hall Nonvertebrate Chordates 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.

End Show 30-1 The Chordates Slide 15 of 25 Copyright Pearson Prentice Hall Nonvertebrate Chordates Mouth Waste- eliminating organ Hollow nerve cord Tail Notochord Intestine Stomach Heart Larva Tunicates The larval form of filter-feeding tunicates have all of the chordate characteristics. Pharynx with gill slits

End Show 30-1 The Chordates Slide 16 of 25 Copyright Pearson Prentice Hall Adult filter-feeding tunicates have neither a notochord nor a tail. Tunic Heart Pharynx with gill slits Siphon to mouth Siphon from anus Anus Intestine Reproductive organs Stomach Adult Nonvertebrate Chordates

End Show 30-1 The Chordates Slide 17 of 25 Copyright Pearson Prentice Hall Tunicates

End Show 30-1 The Chordates Slide 18 of 25 Copyright Pearson Prentice Hall Lancelets Lancelets are small, fishlike creatures that live on the ocean bottom. Mouth Pharynx with gill slits Reproductive organs Intestine Anus Tail Segmented muscles Notochord Hollow nerve cord Nonvertebrate Chordates

End Show 30-1 The Chordates Slide 19 of 25 Copyright Pearson Prentice Hall 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. Mouth Pharynx with gill slits Nonvertebrate Chordates

End Show 30-1 The Chordates Slide 20 of 25 Copyright Pearson Prentice Hall 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. Nonvertebrate Chordates

End Show 30-1 The Chordates Slide 21 of 25 Copyright Pearson Prentice Hall Lancelet

End Show - or - Continue to: Click to Launch: Slide 22 of 25 Copyright Pearson Prentice Hall 30-1

End Show Slide 23 of 25 Copyright Pearson Prentice Hall 30-1 A characteristic of most, but not all, chordates is a.pharyngeal pouches. b.a backbone. c.a hollow nerve cord. d.a tail that extends beyond the anus.

End Show Slide 24 of 25 Copyright Pearson Prentice Hall 30-1 In vertebrates, the developing backbone replaces the a.pharyngeal pouches. b.hollow nerve cord. c.notochord. d.siphon and tunic.

End Show Slide 25 of 25 Copyright Pearson Prentice Hall 30-1 To which group of vertebrates are tunicates most closely related? a.amphibians b.fishes c.reptiles d.mammals

End Show Slide 26 of 25 Copyright Pearson Prentice Hall 30-1 An animal that retains a notochord as an adult is a a.tunicate. b.lancelet. c.fish. d.reptile.

End Show Slide 27 of 25 Copyright Pearson Prentice Hall 30-1 In the lancelet, the pharynx and gill slits are used for a.feeding and gas exchange. b.reproduction and excretion. c.circulation and sensory detection. d.movement and digestion.

END OF SECTION