section 1: echinoderm characteristics

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Chapter 27 Echinoderms and Invertebrate. Chordates. Section 1: Echinoderm Characteristics. Section 2: Invertebrate Chordates. Echinoderms and Invertebrate Chordates. Chapter 27. 27.1 Echinoderm Characteristics. Echinoderms are deuterostomes. - PowerPoint PPT Presentation


  • Echinoderms are deuterostomes.27.1 Echinoderm CharacteristicsEchinoderms and Invertebrate ChordatesThe approximately 6000 living species of echinoderms are marine animals.Chapter 27

  • Body StructureEchinoderms and Invertebrate ChordatesThe endoskeleton consists of calcium carbonate plates covered by a thin layer of skin.Pedicellariae aid in catching food and in removing foreign materials from the skin.27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesAdult brittle starEchinoderm larvae have bilateral symmetry.All echinoderms have radial symmetry as adults.27.1 Echinoderm CharacteristicsChapter 27

  • Water-vascular SystemEchinoderms and Invertebrate ChordatesThe water-vascular system is a system of fluid-filled, closed tubes that work together to enable echinoderms to move and get food.Tube feet are small, muscular, fluid-filled tubes that end in suction-cuplike structures and are used in movement, food collection, and respiration.27.1 Echinoderm CharacteristicsChapter 27

  • Feeding and DigestionEchinoderms and Invertebrate ChordatesExtend their arms and trap foodPush their stomachs out of their mouths and onto their preyTrap organic materials in mucus on their armsScrape algae off surfaces27.1 Echinoderm CharacteristicsChapter 27

  • Respiration, Circulation, and ExcretionEchinoderms and Invertebrate ChordatesOxygen diffuses from the water through the thin membranes of the tube feet.Circulation takes place in the body coelom and the water-vascular system.Excretion occurs by diffusion through thin body membranes.27.1 Echinoderm CharacteristicsChapter 27

  • Response to StimuliEchinoderms and Invertebrate ChordatesSensory neurons respond to touch, chemicals dissolved in the water, water currents, and light.27.1 Echinoderm CharacteristicsChapter 27

  • MovementEchinoderms and Invertebrate ChordatesThe structure of the endoskeleton is important for determining the type of movement an echinoderm can undertake.Swimming CrawlingBurrowing27.1 Echinoderm CharacteristicsChapter 27

  • Reproduction and DevelopmentEchinoderms and Invertebrate ChordatesMost echinoderms reproduce sexually.Echinoderms can regenerate lost body parts. 27.1 Echinoderm CharacteristicsChapter 27

  • Sea StarsEchinoderms and Invertebrate ChordatesFive arms arranged around a central diskA single tube foot can exert a pull of 0.250.30N.Might have as many as 2000 tube feet27.1 Echinoderm CharacteristicsChapter 27

  • Brittle StarsEchinoderms and Invertebrate ChordatesMost brittle stars have five arms.Arms are thin and very flexible.Move by rowing themselves quickly over the bottom rocks and sedimentsBrittle star27.1 Echinoderm CharacteristicsChapter 27

  • Sea Urchins and Sand DollarsEchinoderms and Invertebrate ChordatesSand dollars can be found in shallow water burrowing into the sand.Sea urchins burrow into rocky areas.Tests reflect the five-part pattern of arms.Sea urchins can be herbivorous grazers or predators.Sand dollars filter organic particles.27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesSand dollarSea urchin27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesSea Lilies and Feather StarsSessile for part of their lives.Can detach themselves and move elsewhereCapture food by extending their tube feet and arms into the water where they catch suspended organic materialsFeather star27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesSea CucumbersTube feet are modified to form tentacles which extend from around their mouths to trap suspended food particles.Tentacles are covered with mucus.When threatened, it can cast out some of its internal organs through its anus.Sea cucumber27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesSea DaisiesLess than 1 cm in diameterDisc-shaped with no armsTube feet are located around the edge of the disc.Sea daisies27.1 Echinoderm CharacteristicsChapter 27

  • Echinoderms and Invertebrate ChordatesChapter 27

  • Echinoderms and Invertebrate ChordatesEcology of EchinodermsSea cucumbers and sea urchins are sources of food.Commensal relationships exist between some echinoderms and other marine animals.27.1 Echinoderm CharacteristicsChapter 27

  • Invertebrate Chordate Features27.2 Invertebrate ChordatesEchinoderms and Invertebrate ChordatesLanceletFossil evidence and recent molecular data show that the amphioxus, or lancelet, is one of the closest living relatives of vertebrates.Chapter 27

  • Chordates have four distinctive features.Echinoderms and Invertebrate ChordatesA dorsal tubular nerve cordA notochordPharyngeal pouchesA postanal tail27.2 Invertebrate ChordatesChapter 27

  • The notochord is a flexible, rodlike structure that extends the length of the body.Echinoderms and Invertebrate ChordatesA notochord made fishlike swimming possible.27.2 Invertebrate ChordatesChapter 27

  • A postanal tail is a structure used primarily for locomotion and is located behind the digestive system and anus.Echinoderms and Invertebrate Chordates27.2 Invertebrate ChordatesChapter 27

  • The dorsal tubular nerve cord is located dorsal to the digestive organs and is a tube shape.Echinoderms and Invertebrate ChordatesThe anterior end of this cord becomes the brain and the posterior end becomes the spinal cord during development of most chordates.27.2 Invertebrate ChordatesChapter 27

  • Pharyngeal pouches were used first for filter feeding and later evolved into gills for gas exchange in water.Echinoderms and Invertebrate ChordatesIn terrestrial chordates, pharyngeal pouches developed into the tonsils and the thymus gland.27.2 Invertebrate ChordatesChapter 27

  • Diversity of Invertebrate ChordatesEchinoderms and Invertebrate ChordatesAll invertebrate chordates are marine animals.23 species of lancelets1250 species of tunicates27.2 Invertebrate ChordatesChapter 27

  • LanceletsEchinoderms and Invertebrate ChordatesBurrow their bodies into the sand in shallow seasFilter feeds27.2 Invertebrate ChordatesChapter 27

  • Echinoderms and Invertebrate ChordatesThe nervous system consists of main branching nerves and a simple brain.27.2 Invertebrate ChordatesChapter 27Swim with a fishlike motion

  • TunicatesEchinoderms and Invertebrate ChordatesSessileOnly in the larval stages do they show typical chordate featuresFood particles are trapped in a mucous net and moved into the stomach where digestion takes place.27.2 Invertebrate ChordatesChapter 27

  • Echinoderms and Invertebrate ChordatesCirculation is performed by a heart and blood vessels that deliver nutrients and oxygen to body organs.27.2 Invertebrate ChordatesChapter 27The only chordate feature that remains in the adult tunicate is pharyngeal gill slits.

  • Echinoderms and Invertebrate ChordatesChapter Resource MenuChapter Diagnostic QuestionsFormative Test QuestionsChapter Assessment QuestionsStandardized Test Practicebiologygmh.comGlencoe Biology TransparenciesImage BankVocabularyAnimationClick on a hyperlink to view the corresponding feature.Chapter 27

  • ABCDCDQ 1Which is not an echinoderm? sea cucumber sand dollar cuttlefish feather starEchinoderms and Invertebrate ChordatesChapter Diagnostic QuestionsChapter 27

  • ABCDCDQ 2Echinoderms and Invertebrate ChordatesChapter Diagnostic QuestionsChapter 27What type of symmetry is typical of adult echinoderms? radial bilateral asymmetry planar

  • ABCDCDQ 3Echinoderms and Invertebrate ChordatesChapter Diagnostic QuestionsChapter 27How do pedicellariae function? frighten predators catch food remove wastes move the echinoderm

  • ABCDFQ 1Echinoderms and Invertebrate ChordatesChapter 27What characteristic does a starfish have that an octopus and beetle do not have? a coelom an endoskeleton bilateral symmetry segmentation27.1 Formative Questions

  • ABCDFQ 2Echinoderms and Invertebrate ChordatesChapter 2727.1 Formative QuestionsHow are echinoderms closely related to animals that have bilateral symmetry? They have a segmented coelom. They have radial segmentation. Their larvae have bilateral symmetry. Their nervous system is advanced.

  • ABCDFQ 3Echinoderms and Invertebrate ChordatesChapter 2727.1 Formative QuestionsWhat is the term for the fluid-filled tubes that enable echinoderms to move and get food? hydroradial apparatus madreporite assemblage radial-canal junction water-vascular system

  • ABCDFQ 4Echinoderms and Invertebrate ChordatesChapter 2727.1 Formative QuestionsWhy are sea urchins and sea cucumbers called bioturbators? They create water currents. They have spiral bodies. They move in circles. They stir up sediment.

  • ABCDFQ 5Echinoderms and Invertebrate ChordatesChapter 27What feature does a lancelet and a tunicate lack? a backbone a dorsal nerve cord a notochord a postanal tail27.2 Formative Questions

  • ABCDFQ 6Echinoderms and Invertebrate ChordatesChapter 2727.2 Formative QuestionsWhat feature is unique to chordates? a postanal tail segmentation deuterostome development an endoskeleton

  • ABCDFQ 7Echinoderms and Invertebrate ChordatesChapter 2727.2 Formative QuestionsWhich animals on the cladogram are believed to be the first vertebrates? tunicates lancelets hagfish lampreys

  • Explain the benefit of regeneration in echinoderms. Echinoderms and Invertebrate ChordatesChapter Assessment QuestionsChapter 27CAQ 1

  • ABCDCAQ 2Echinoderms and Invertebrate ChordatesChapter 27Which structure of the chordate allows for side-to-side movements? dorsal tubular nerve cord notochord phar


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