1. 29.1 Section Objectives – page 763 Compare similarities and differences among the classes of echinoderms. Section Objectives: 29.1 Interpret the evidence biologists have for determining that echinoderms are close relatives of chordates.

2. Section 29.1 Summary – pages 763-769 _________ move by means of hundreds of hydraulic, suction-cup-tipped appendages and have skin covered with tiny, jawlike pincers. Echinoderms are found in all the _____ of the world.

3. Section 29.1 Summary – pages 763-769 If you were to examine the skin of several different echinoderms, you would find that they all have a hard, _____, or bumpy endoskeleton covered by a thin ________.

4. Section 29.1 Summary – pages 763-769 ___ ___, sometimes called starfishes, may not appear spiny at first glance, but a close look reveals that their long, tapering arms, called ___, are covered with short, rounded spines.

5. Section 29.1 Summary – pages 763-769 Some of the spines found on sea stars and ___ _____ have become modified into pincer-like appendages called _________ (PEH dih sih LAHR ee ay).

6. Section 29.1 Summary – pages 763-769 An echinoderm uses its jaw-like _______ for protection and for cleaning the surface of its body. Pedicellariae

7. Section 29.1 Summary – pages 763-769 You may remember that ____________is an advantage to animals that are stationary or move slowly. Radial symmetry enables these animals to sense potential food, predators, and other aspects of their environment from all directions.

8. Section 29.1 Summary – pages 763-769 The water vascular system is a _____ system that operates under water pressure. Water enters and leaves the water vascular system of a sea star through the _______ (mah druh POHR ite), a sieve-like, disk- shaped opening on the upper surface of the echinoderm’s body.

9. Section 29.1 Summary – pages 763-769 The underside of a sea star has ____ feet that run along a groove on the underside of each ray.

10. Section 29.1 Summary – pages 763-769 Tube feet are hollow, thin-walled tubes that end in a ______ cup. Tube feet look somewhat like miniature droppers. The round, muscular structure called the ______ (AM pew lah) works something like the bulb of a dropper.

11. Section 29.1 Summary – pages 763-769 Each ____ foot works independently of the others, and the animal moves along slowly by alternately pushing out and pulling in its tube feet. Ampullae

12. Section 29.1 Summary – pages 763-769 Tube feet also function in gas exchange and excretion. Gases are exchanged and wastes are eliminated by ________ through the thin walls of the tube feet.

13. Section 29.1 Summary – pages 763-769 All echinoderms have a mouth, stomach, and intestines, but their methods of obtaining food vary. Sea stars are _________ and prey on worms or on mollusks such as clams.

14. Section 29.1 Summary – pages 763-769 Most sea urchins are ___________ and graze on algae. ______ stars, ___ lilies, and sea _______ feed on dead and decaying matter that drifts down to the ocean floor.

15. Section 29.1 Summary – pages 763-769 Echinoderms have no head or brain, but they do have a ____ ____ ____ that surrounds the mouth. Ring canal

16. Section 29.1 Summary – pages 763-769 Nerves extend from the _____ ____down each ray. Each ______ nerve then branches into a nerve net that provides sensory information to the animal.

17. Section 29.1 Summary – pages 763-769 ___ ____are an exception. A sea star’s body consists of long, tapering rays that extend from the animal’s central disk. A sensory organ known as an ______ and consisting of a cluster of light-detecting cells is located at the tip of each arm, on the underside.

18. Section 29.1 Summary – pages 763-769 _______ enable sea stars to detect the intensity of light. Sea stars also have chemical ______ on their tube feet.

19. Section 29.1 Summary – pages 763-769 If you examine the larval stages of echinoderms, you will find that they have ___________ ______. Through __________, the free-swimming larvae make dramatic changes in both body parts and in symmetry.

20. Section 29.1 Summary – pages 763-769 Echinoderms are deuterostomes. This pattern of development indicates a close relationship to ______, which are also deuterostomes.

21. Section 29.1 Summary – pages 763-769 Approximately 6000 species of echinoderms exist today. About one-fourth of these species are in the class _______ (AS tuh ROY dee uh), to which the sea stars belong.

22. Section 29.1 Summary – pages 763-769 The five other classes of living echinodems are Ophiuroidea (OH fee uh ROY dee uh), the brittle stars; Echinoidea (eh kihn OY dee uh), the sea urchins and sand dollars.

23. Section 29.1 Summary – pages 763-769 Holothuroidea (HOH loh thuh ROY dee uh), the sea cucumbers; Crinoidea (cry NOY dee uh), the sea lilies and feather stars; and Concentricycloidea (kon sen tri sy CLOY dee uh), the sea daisies. Sea Cucumber

24. Section 29.1 Summary – pages 763-769 Most species of sea stars have ____ rays, but some have more. Some species may have more than 40 rays.

25. Section 29.1 Summary – pages 763-769 Brittle stars are extremely ______. This adaptation helps the brittle star survive an attack by a predator. While the predator is busy with the broken off ray, the brittle star can escape. A new ray will ________.

26. Section 29.1 Summary – pages 763-769 Brittle stars propel themselves with the snake like, slithering motion of their flexible rays. They use their tube feet to pass particles of food along the rays and into the mouth in the ____ ____.

27. Section 29.1 Summary – pages 763-769 Sea urchins and sand dollars are _____ or disk-shaped animals covered with spines; they do not have rays. A living sand dollar is covered with minute, hair-like spines that are lost when the animal dies. A sand dollar has tube feet that protrude from the petal-like markings on its upper surface.

28. Section 29.1 Summary – pages 763-769 These tube feet are modified into ____ and are used for respiration. Tube feet on the animal’s bottom surface aid in bringing food particles to the mouth.

29. Section 29.1 Summary – pages 763-769 Sea urchins look like living pincushions, bristling with long, usually pointed spines. Sea urchins have long, slender tube feet that, along with the spines, aid the animal in ________.

30. Section 29.1 Summary – pages 763-769 Sea cucumbers are so called because of their vegetable-like appearance. Their leathery covering allows them flexibility as they move along the ocean floor.

31. Section 29.1 Summary – pages 763-769 When sea cucumbers are threatened, they may expel a tangled, sticky mass of tubes through the anus, or they may rupture, releasing some internal organs that are _______ in a few weeks. Sea cucumbers reproduce by shedding ____ and _____ into the water, where fertilization occurs.

32. Section 29.1 Summary – pages 763-769 Sea lilies and feather stars resemble plants in some ways. Sea lilies are the only ______ echinoderms. Feather stars are sessile only in _____form. The adult feather star uses its feathery arms to swim from place to place.

33. Section 29.1 Summary – pages 763-769 Sea daisies are flat, disk-shaped animals less than 1 cm in diameter. Their tube feet are located around the edge of the disk rather than along radial lines, as in other echinoderms.

34. Section 29.1 Summary – pages 763-769 The earliest echinoderms may have been bilaterally symmetrical as adults, and probably were attached to the ocean floor by _______. Another view of the earliest echinoderms is that they were bilateral and ____ swimming.

35. Section 29.1 Summary – pages 763-769 The echinoderms represent the only major group of deuterostome ___________. This pattern of development is one piece of evidence biologists have for placing echinoderms as the closest invertebrate relatives of the ________.

36. Section 29.1 Summary – pages 763-769 Most echinoderms have been found as fossils from the early Paleozoic Era. Fossils of brittle stars are found beginning at a later period. Not much is known about the origin of sea daisies.

37. 29.2 Section Objectives – page 770 Summarize the characteristics of chordates. Section Objectives: 29.2 Explain how invertebrate chordates are related to vertebrates. Distinguish between sea squirts and lancelets.

38. Section 29.2 Summary – pages 770-775 The phylum _________includes three subphyla: Urochordata, the ________ (sea squirts); Cephalochordata, the ______; and Vertebrata, the vertebrates. Invertebrate chordates have a ______, a dorsal hollow nerve cord, ______pouches, and a ______ tail at some time during their development.

39. Section 29.2 Summary – pages 770-775 In addition, all chordates have ______ symmetry, a well-developed ______, and segmentation. Postanal tail Anus Muscle blocks Pharyngeal pouches Mouth Dorsal hollow nerve cord Notochord

40. Section 29.2 Summary – pages 770-775 The embryos of all chordates have a _____ (NOH tuh kord) — a long, semirigid, rod-like structure located between the digestive system and the dorsal hollow nerve cord. Gill slits Nerve cord Notochord

41. Section 29.2 Summary – pages 770-775 In invertebrate chordates, the notochord may be retained into adulthood. But in vertebrate chordates, this structure is replaced by a _______. ________ chordates do not develop a backbone.

42. Section 29.2 Summary – pages 770-775 The pharyngeal pouches of a chordate embryo are paired openings located in the _______, behind the mouth. In aquatic chordates, pharyngeal pouches develop openings called _____ ____. In terrestrial chordates, pharyngeal pouches develop into other structures.

43. Section 29.2 Summary – pages 770-775 At some point in development, all chordates have a _____ tail. Humans are chordates, and during the early development of the human _____, there is a postanal tail that disappears as development continues. Postanal tail

44. Section 29.2 Summary – pages 770-775 In most animals that have tails, the digestive system extends to the tip of the tail, where the ____ is located. _______, however, usually have a tail that extends beyond the anus.

45. Section 29.2 Summary – pages 770-775 Muscle _____ aid in movement of the tail. Muscle blocks are modified body segments that consist of _______ muscle layers. Muscle blocks are anchored by the notochord, which gives the muscles a firm structure to pull against.

46. Section 29.2 Summary – pages 770-775 _______ genes specify body organization and direct the development of tissues and organs in an embryo. Studies of chordate homeotic genes have helped scientists understand the process of development and the relationship of invertebrate chordates to vertebrate chordates.

47. Section 29.2 Summary – pages 770-775 The invertebrate chordates belong to two subphyla of the phylum chordata: subphylum Urochordata, the tunicates (TEW nuh kaytz), also called sea squirts, and subphylum Cephalochordata, the lancelets.

48. Section 29.2 Summary – pages 770-775 Although adult tunicates do not appear to have any shared chordate features, the _____ stage, has a tail that makes it look similar to a tadpole.

49. Section 29.2 Summary – pages 770-775 Tunicate larvae do not ___and are free swimming after hatching. They soon settle and attach themselves with a sucker to boats, rocks, and the ocean bottom. Many adult tunicates secrete a ____, a tough sac made of _______, around their bodies.

50. Section 29.2 Summary – pages 770-775 Colonies of tunicates sometimes secrete just one big tunic that has a common opening to the outside. Only the ______ ____in adult tunicates indicate their chordate relationship.

51. Section 29.2 Summary – pages 770-775 If you remove a tunicate from its sea home, it might squirt out a jet of water-hence the name sea squirt.

52. Section 29.2 Summary – pages 770-775 ______ are small, streamlined, and common marine animals, usually about 5 cm long. Like tunicates, lancelets are ____ ____.

53. Section 29.2 Summary – pages 770-775 Unlike tunicates, however, lancelets retain all their chordate features throughout life. Postanal tail Anus Muscle blocks Intestine Notochord Dorsal hollow nerve cord Oral hood with tentacles Mouth Gill slits in pharynx

54. Section 29.2 Summary – pages 770-775 Although lancelets look somewhat similar to fishes, they have only one layer of skin, with no pigment and no scales.

55. Section 29.2 Summary – pages 770-775 Lancelets do not have a distinct ____, but they do have light sensitive cells on the _______ end. They also have a ____ that covers the mouth and the sensory _______ surrounding it.

56. Section 29.2 Summary – pages 770-775 Biologist are not sure where sea squirts and lancelets fit in the phylogeny of chordates. According to one hypothesis, echinoderms, invertebrate chordates, and vertebrates all arose from ancestral ______animals that fed by capturing food in tentacles.

57. Section 29.2 Summary – pages 770-775 Recent discoveries of fossil forms of organisms that are similar to living lancelets in rocks 550 million years old show that invertebrate chordates probably existed before vertebrate chordates.