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Echinoderms and : Introduction to the and (pp. 737 – 757,1211-1212)

Sharks

Bony fishes

Lancelet Figure 34.1: phylogeny of the Deuterostomes

Protostomes

This phylum includes that are not : , vertebrates are collectively bony fishes, , known as . Over (including ), 95% of the known and are invertebrates, including the development echinoderms, , and xenoturbellids. Triploblasty Bilateral symmetry Echinoderms have a . Podia project from the underside of the body.

Opening to exterior

Tube foot

Podia Podia

Figure 34.3 Mutable connective tissue

Left photo: when first touched or handled, the stiffens its connective tissue. Right photo: after being rubbed vigorously, the body becomes so soft that it flows between the experimenters fingers. diversity: Asteroidea (Sea stars) Echinoderm diversity: Class Echinoidea (sea urchins, sand dollars) eating kelp Echinoderm 100 diversity: Class 80 Echinoidea 60 40 To really understand number (% max. count) (% max. count) 20 how cool sea urchins 0 are, I must tell you a (a) abundance story about keystone species: 400 300

2

m 200 100

Grams per 0.25 0 (b) Sea urchin biomass

10 8 sea 2 6 4 as keystone species 0.25 m 2 Number per 0 in the N. Pacific 1972 1985 1989 19931997 Food chain before killer (c) Total kelp density Food chain after killer involvement in chain started preying on otters Prey shift in killer whales after sea otters’ numbers have diminished. Echinoderm diversity: Class Holothuroidea (Sea cucumbers) Bizarre defense mechanisms in sea cucumbers: 1. Expel cuverian tubules

2. Eviscerate (water ) are very small animals that live on . They have segmented bodies and unjointed limbs. They grow by molting. Who are they most closely related to? a. b. platyhelminthes c. d. Mollusks e. Figure 34.1: The other large Deuterostome phylum, the Chordata Deuterostomes

Protostomes

This phylum includes Animals that are not vertebrates: sharks, vertebrates are collectively bony fishes, amphibians, known as invertebrates. Over reptiles (including birds), 95% of the known animal species Deuterostome and mammals are invertebrates, including the development echinoderms, hemichordates, Coelom and xenoturbellids. Triploblasty Bilateral symmetry the 4 characteristics Sub-phylum Urochordata: the sea squirts or

They are sessile and often colonial Sea squirts possess pharyngeal slits:

Fig 34.5a: But where is the ? The dorsal hollow cord? the postanal ? The larvae has them!

Fig. 34.5 Urochordata (tunicates) Water flow Adult Pharyngeal slits

Dorsal hollow nerve cord Water flow Notochord

Muscular, Pharyngeal gill slits post-anal tail Cephalochordata: the

Lancelet ( or Amphioxus)

Fig. 34.5b Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn

Deuterostomes CHORDATA Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Vertebrates Pharyngeal gill slits Lancelets possess elaborate with Tunicates CHORDATA large and a cranium, Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail and a .

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned fishes , internal ()

Lungfish Lobed

AMPHIBIA TETRAPODA , toads

Salamanders

Lactation, fur Limbs AMNIOTA Mammals

REPTILIA , Amniotic

Scales with hard

Alligators,

Birds Lampreys (jawless vertebrates)

Sea lampreys (Petromyzon marinus) invaded Lake Ontario in 1830 from the sea. When the Welland Canal was built to bypass Niagara falls (1919), they migrated to the rest of the lakes. The catch of dropped from 15 million pounds at the beginning of the 20th century to ≈ 300,000 in the 60s. Spread of lampreys Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Vertebrates Pharyngeal gill slits Lancelets possess elaborate heads with Tunicates CHORDATA large brains and a cranium Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail and a vertebral column. Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, The Gnathostomata are skates vertebrates that possess Ray finned Jaws fishes SARCOPTERYGII jaws. Coelacanths Lungs, internal bone (endoskeleton)

Lungfish Lobed fins

AMPHIBIA TETRAPODA Frogs, toads

Salamanders

Lactation, fur Limbs AMNIOTA Mammals

REPTILIA Lizards, snakes Amniotic egg

Scales with hard keratin Turtles

Alligators, crocodiles

Birds OF THE Jawless

Gill arches Fig. 34.10: The vertebrate jaw likely Intermediate form ( acanthodian ) evolved from 2 pairs of gill arches Gill (skeletal structures arches that supported the Jaw phayrngeal gill slits)

Fossil

Gill arches Jaw While snorkeling, you come across an animal that is bilaterally symmetrical, has segments, a coelom, does not molt, and whose blastopore forms the mouth. The animal could be a/an: a. Chordate b. c. mollusk d. e. echinoderm Class : Sharks, rays, and chimeras.

chimeras

rays

sharks ≈ 750 species of the cartilagenous fishes. The system that is used to detect tiny vibrations in the water

Neuromasts (tiny pores that open into the lateral line) Sharks have internal fertilization and a diversity of reproductive modes

Claspers are paired sperm-transfer organs of male sharks

Mating bull sharks viviparous oviparous:

Shark propaganda….. Bony Vertebrates This include 3 taxa (classes) of“fishes” and (amphibians, reptiles and mammals).

Examples of “fishes”:

Hypopocampus erectus Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Bony Vertebrates Pharyngeal gill slits Lancelets include 3 taxa of fish, and Tunicates CHORDATA tetrapods (amphibians, Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail mammals and reptiles): Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned Jaws fishes SARCOPTERYGII Coelacanths Lungs, internal bone (endoskeleton)

Lungfish Lobed fins

AMPHIBIA TETRAPODA Frogs, toads

Salamanders

Lactation, fur Limbs AMNIOTA Mammals

REPTILIA Lizards, snakes Amniotic egg

Scales with hard keratin Turtles

Alligators, crocodiles

Birds Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Bony Vertebrates Pharyngeal gill slits Lancelets include 3 taxa of fish, and Tunicates CHORDATA tetrapods (amphibians, Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail mammals and reptiles): Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned How would you describe the Jaws fishes SARCOPTERYGII Coelacanths phylogeny of fish (highlightedLungs, internal bone (endoskeleton)

Lungfish in )? Lobed fins AMPHIBIA TETRAPODA a.Aphyletic Frogs, toads b.Monophyletic Salamanders Lactation, fur Limbs AMNIOTA c.Oligophyletic Mammals REPTILIA Lizards, snakes d.Paraphyletic Amniotic egg e.polyphyletic Scales with hard keratin Turtles Alligators, crocodiles

Birds Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Bony Vertebrates Pharyngeal gill slits Lancelets include the fish, and Tunicates CHORDATA tetrapods (amphibians, Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail mammals and reptiles): Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned How would you describe the Jaws fishes SARCOPTERYGII Coelacanths phylogeny of ChondricthyesLungs, internal bone (endoskeleton)

Lungfish (sharks)? Lobed fins AMPHIBIA TETRAPODA a.Aphyletic Frogs, toads b.Monophyletic Salamanders Lactation, fur Limbs AMNIOTA c.Oligophyletic Mammals REPTILIA Lizards, snakes d.Paraphyletic Amniotic egg e.polyphyletic Scales with hard keratin Turtles Alligators, crocodiles

Birds Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: Bony Vertebrates Pharyngeal gill slits Lancelets include the fish, and Tunicates CHORDATA tetrapods (amphibians, Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail mammals and reptiles): Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned Although, fishes are Jaws fishes SARCOPTERYGII Coelacanths paraphyletic,the “fish” are Lungs, internal bone (endoskeleton)

Lungfish composed of 6 monophyletic Lobed fins AMPHIBIA TETRAPODA lineages (see 6 blue lines) Frogs, toads

Salamanders

Lactation, fur Limbs AMNIOTA Mammals

REPTILIA Lizards, snakes Amniotic egg

Scales with hard keratin Turtles

Alligators, crocodiles

Birds The ray-finned fishes have all sorts of fins that can be greatly modified.

Scorpion fish Traits of ray-finned fishes:

swimbladder Radial symmetry Echinoderms Water vascular system Loss of pharyngeal gill slits Protostomes Outgroups to Chordata Acorn worms

Deuterostomes CHORDATA Xenoturbella Loss of pharyngeal gill slits

CHORDATA Fig. 34.12: The aquatic bony Pharyngeal gill slits Lancelets vertebrates also include the Tunicates CHORDATA (a lobe-finned Dorsal hollow nerve cord Notochord VERTEBRATA Muscular, post-anal tail fish). Hagfish

Lampreys

GNATHOSTOMATA Vertebrae, cranium Sharks, rays, skates

Ray finned Jaws fishes SARCOPTERYGII Coelacanths Lungs, internal bone (endoskeleton)

Lungfish Lobed fins

AMPHIBIA TETRAPODA Frogs, toads

Salamanders

Lactation, fur Limbs AMNIOTA Mammals

REPTILIA Lizards, snakes Amniotic egg

Scales with hard keratin Turtles

Alligators, crocodiles

Birds Lungfishes (6 species) are found in , , and . All have a pair of lungs. fish have a transparent “forehead” and that can pivot!