Echinoderms & Chordates

Phylum Echinodermata (echinoderms) About 6,000 species All _______________

Phylum Echinodermata (echinoderms) Eucoelomates, triploblastic

Phylum Echinodermata (echinoderms) Eucoelomates, triploblastic Pentamerous (5-part) radial symmetry as adults Parts arranged around oral/aboral axis

Phylum Echinodermata (echinoderms) Why not in ___________? Larva bilaterally symmetrical!

Phylum Echinodermata (echinoderms) Calcareous endoskeleton. Plates form surrounded by tissues. Arises from mesoderm. “echino-” means spiny, “-derm” means skin.

Phylum Echinodermata Water vascular system in _____________ Connect to tube feet Note madreporite on aboral surface of starfish (takes water into system)

Phylum Echinodermata Tube feet in action

Phylum Echinodermata (echinoderms) Complete digestive system Reproduction: have good regeneration abilities, some can break into parts and reproduce asexually.

Phylum Echinodermata (echinoderms) Most reproduce sexually Dioecious, fertilization external

Phylum Echinodermata No head or well developed brain (nerve ring) No excretory organs (no flame cells, nephridia, etc.) No respiratory system (tube feet and papulae help exchange gases)

Phylum Echinodermata (echinoderms) Deuterostomes

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Class Asteroidea (sea stars) Class Ophiuroidea (brittle stars) Class Echinoidea (sand dollars and sea urchins) Class Holothuroidea (sea cucumbers)

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Sessile for some or all of life. Add new __________ as they grow. Have mouth and anus on upper surface.

Phylum Echinodermata Class Crinoidea (sea lilies/feather stars) Glorious fossil past (6000 fossil species, 600 living ones). Wisconsin

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Class Asteroidea (sea stars) Class Ophiuroidea (brittle stars) Class Echinoidea (sand dollars and sea urchins) Class Holothuroidea (sea cucumbers)

Phylum Echinodermata (echinoderms) Class Asteroidea (sea stars) 1500 species. Active and important marine predators Move about on tube feet

Phylum Echinodermata (echinoderms) Class Asteroidea (sea stars) Predation may cause problems Ex, crown of thorns starfish (coral predator)

Phylum Echinodermata (echinoderms) Class Asteroidea (sea stars) The rest of the story: part of problem may be overcollecting of tritons, a gastropod that preys on these starfish

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Class Asteroidea (sea stars) Class Ophiuroidea (brittle stars) Class Echinoidea (sand dollars and sea urchins) Class Holothuroidea (sea cucumbers)

Phylum Echinodermata (echinoderms) Class Ophiuroidea (brittle stars) 2000 species. Abundant, nocturnal. Move using two arms at a time Feed on plankton and organic debris with tube feet.

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Class Asteroidea (sea stars) Class Ophiuroidea (brittle stars) Class Echinoidea (sand dollars and sea urchins) Class Holothuroidea (sea cucumbers)

Phylum Echinodermata Class Echinoidea (sea urchins/sand dollars) Lack arms. 1000 species. Endoskeleton of fused calcareous plates No arms or rays. Have rows of spines and tube feet. Spines and feet moveable.

Phylum Echinodermata (echinoderms) Class Echinoidea (sea urchins/sand dollars) Sea urchins: long spines Sand dollars: short spines

Phylum Echinodermata (echinoderms) Class Echinoidea (sea urchins/sand dollars) Pedicillariae. Discourage small invertebrates from settling on surface.

Phylum Echinodermata (echinoderms) Class Echinoidea (sea urchins/sand dollars) Aristotle’s lantern: complex chewing apparatus.

Phylum Echinodermata Can be important members of marine ecosystems Ex, sea urchins as herbivores

Urchins, sea otters, and kelps Sea otters hunted almost to extinction on West Coast Now expanding back Top carnivores (almost): eat mussels, abalone, sea urchins. Purple sea urchin

Urchins, sea otters, and kelps Urchins eat __________ of kelp Fewer urchins now that otters are back.

Urchins, sea otters, and kelps Giant kelp forests recovering as otters return. Fish and other associates rebounding.

Sea urchins Eggs (roe) edible, delicacy (known as uni in sushi bars)

Phylum Echinodermata (echinoderms) Class Crinoidea (sea lilies/feather stars) Class Asteroidea (sea stars) Class Ophiuroidea (brittle stars) Class Echinoidea (sand dollars and sea urchins) Class Holothuroidea (sea cucumbers)

Phylum Echinodermata Class Holothuroidea (sea cucumbers) Elongate Soft bodied (endoskeleton plates reduced or absent) Often with feeding tentacles around mouth

Phylum Echinodermata Class Holothuroidea (sea cucumbers) Have respiratory organ (respiratory tree) (11, F), arising from cloaca (12, G: near anus, 13) Gonads (8, H) Intestine (10, I)

Phylum Echinodermata Class Holothuroidea (sea cucumbers) Symbiosis story: black pearlfish can be found living in _________ of sea cucumbers

Phylum Echinodermata Class Holothuroidea (sea cucumbers) Sea cucumber defense tactic: regurgitate internal organs and _____________ them later

Phylum Echinodermata (echinoderms) Class Holothuroidea (sea cucumbers) Edible: braised sea cucumber with tea leaves

Phylum Chordata (chordates) About 43,000 species Triploblastic, eucoelomates

Phylum Chordata (chordates) Bilateral symmetry Deuterostomes

Segmentation Present in chordates Often visible in embryo

Internal skeleton Differs from echinoderms. Rodlike, deeper in body. Gives attachment points for muscles. Human skeleton

4 Key Features 1) Hollow (tubular!) nerve cord under *dorsal* surface

4 Key Features 1) Hollow (tubular!) nerve cord under *dorsal* surface Becomes brain and spinal cord *Invertebrates usually have ventral nerve cords.

4 Key Features 2) Notochord: flexible rod just under nerve cord. Originally served as muscle attachment point

4 Key Features 3) Pharyngeal pouches in embryo In humans, only one remains to form Eustachian tubes connecting inner ear to __________.

4 Key Features 4) Postanal tail (at least during embryonic stages). Nearly all other animals with terminal anus

Chordate survey Subphylum Urochordata (tunicates) Subphylum Cephalochordata (lancelets) Subphylum Vertebrata (vertebrates)

Chordate survey Subphylum Urochordata (tunicates) Marine. 1300 species.

Chordate survey Subphylum Urochordata (tunicates) Adult sessile, filter feeder. Has holdfast, siphons (incurrent & excurrent, pharynx). Cilia in pharynx create water current.

Chordate survey Subphylum Urochordata (tunicates) Pharynx used to feed, traps food in mucus on endostyle Pharynx has gill slits for breathing Many adults secrete tunic: tough sac of ______________ around body.

Chordate survey Subphylum Urochordata (tunicates) Subphylum Cephalochordata (lancelets) Subphylum Vertebrata (vertebrates)

Chordate survey Subphylum Cephalochordata (lancelets) Marine. 20 species. Ex, Amphioxus or Branchiostoma

Chordate survey Subphylum Cephalochordata (lancelets) Filter feeder, can swim Oral hood has tentacles (sensory) Cilia create water current, used for breathing and filter feeding. Water exits via _________________.

Chordate survey Subphylum Cephalochordata (lancelets) No head, brain, eyes, etc. Skin only 1 cell layer thick (vertebrates with multi-layered skin) ________________: segmented muscles.

Chordate survey Subphylum Cephalochordata (lancelets) Model version (as seen in lab)

Chordate survey Subphylum Urochordata (tunicates) Subphylum Cephalochordata (lancelets) Subphylum Vertebrata (vertebrates)

Subphylum Vertebrata (vertebrates) Distinctive features 1) Have vertebral column. Bony segments replace __________, enclose spinal cord

Subphylum Vertebrata (vertebrates) Distinctive features 2) Have well-developed head (with skull and brain)

Subphylum Vertebrata (vertebrates) Other features 3) Neural crest in embryo. Cells migrate to form many tissues (parts of muscle, nerve, skin, systems, etc.) in various places in body.

Subphylum Vertebrata (vertebrates) Other features 4) Internal organs: liver, kidneys, endocrine glands, heart and closed circulatory system 5) Endoskeleton of _________ (protein) or bone (protein and calcium crystals). Bone strong but not brittle. Can make big bodies this way.

Chordate survey Subphylum Vertebrata (vertebrates) Class Agnatha Class Chondrichthyes Class Osteichthyes Class Amphibia Class Reptilia Class Aves Class Mammalia