Chapter 34: DEUTEROSTOMES

Which of the following structures is not a component of the watervascular system of an echinoderm?

Ossicles

Which of the following is the closest relative of lungfish?

Ray-finned fish

During embryonic development, a neural crest would be found in all of the following chordates, except

cephalochordates.

All of the following are characteristics of reptiles, except

cutaneous respiration

Although the traditional classification will be used in this chapter, what vertebrate groups display paraphyly?

fish and reptiles

The ___ of the bony fish evolved to counter the effects of increased bone density

swim bladder

List the characteristics that define chordates

-endoskeleton is TRULY internal -

What is the origin of the vertebral column both in an evolutionary context and during embryonic development.

-first appeared 545 MYA -

What are distinguishing characteristics of vertebrates?

-have vertebral column (protects the dorsal nerve cord) -head (distinct and well-differentiated possessing) -neural crest (unique group of embryonic cells that forms structures) -Internal organs(liver, kindey, endocrine glands, heart, closed circulatory system) -endoskeleton (made of cartilage and bone)

Briefly list and describe the characteristics of echinoderms.

-spiny-skinned animals -sea stars, brittle stars, sea urchins, sand dollars, sea cucumbers -exclusively marine -deuterostome development -endoskeleton -pentaradial symmetry -appeared nearly 600 MYA in the Cambrian -thought to have evolved from bilaterally symmetrical ancestors because larvae are bilaterally symmetrical

List and briefly describe five key characteristics of fishes.

-vertebral column (ex. hagfish and lamprey) -jaws and paired appendages (hagfish and lamprey exceptions) (two pairs: pectoral and pelvic fin pairs-- lobe-fined fish with a core of jointed bones) -internal gills -single-loop blood circulation -nutritional deficiencies (inability to synthesize aromatic amino acids)

Describe the basic body form of an echinoderm including the following features: water vascular system, ossicles, madreporite, tube feet, pentaradial, and radial canals.

-water vascular sys: radially organized; radial canal extends from ring canal into each body branch; water enters through madreporite; flows through the stone canal to ring canal; tube feet used in movement, gas exchange, and feeding. The ampulla has a muscular sac at the base.

List (both formal and common names) and briefly describe the five living classes of echinoderms.

1. Class Asteroidea (sea stars and daisies) -important predators -found in intertidal zones and deep ocean -5 arms -body covered w/ pigmented epiermis 2. Class Holothuroidea (sea cucumbers) - 3. Class Echinoidea (sea urchins, sand dollars) -lack arms -5 double rows of tube feet (protrude through calcareous skeletal plates) -protective movable spines -sand dollars are flattened sea urchins 4. Class Crinoidea (sea lilies, feather stars) 5. Class Ophiuroidea (brittle stars) -largest class -brittle stars -arms are easily automized -tube feet lack ampullae (used for feeding, not moving) -no anus; waste eliminated through mouth

Regarding the extant Agnatha ("jawless fishes"), list both formal and common names for the two groups and write a brief description for each.

1. Class Myxini (hagfish) -jawless fish with no paired appendages; scavengers; mostly blind; good sense of smell 2. Class Cephalaspidomorphi (lampreys) -largely extinct group of jawless fish with no paired appendages; parasitic and nonparasitic types all breed in freshwater

There are two invertebrate chordate subphyla. List (both formal and common names) and describe each group's defining characteristics

1. Subphylum Urochordata (turnicates or sea squirts) -marine animals -larvae are tadpole-like and have nootochord and nerve chord -adults lose the tail and notochord -immobile filter-feeders -no major body cavity or segmentation -secrete a tunic (cellulose sac) that surrounds the animal 2. Subphylum Cephalochordata (lancelets) -scaleless chordates -notochord persists throughout animals life -partly buried -no distinguishable head -feed on plankton using cilia-generated currents -closest relative to vertebrates

Echinoderms are part related to other bilateria, yet they are pentaradial as adults. How can this be?

Their early developmental life/history shows ancestors were bilateral symmetrical. Echinoderms are bilateral symmetrical. Their ancestors evolved to have pentaradial adult forms but their larvae still display the bilateral symmetry of their ancestors.

Regarding amphibians: (a.) What are the five distinguishing characteristics of amphibians? (b.) List and briefly describe three extant orders of amphibians.

a) -legs (adaptation to life on land) -lungs -cutaneous respiration (supplement lungs) -pulmonary veins (separate pulmonary circuit allows higher pressure blood to tissues) -partially divided heart (improves separation of pulmonary and systematic circuits) b) -Anura: frogs and toads; they are compact, tailless body, large head fused to the trunk, rear li,bs specialized for jumping -Caudata: salamanders and newts; slender body, long tail and limbs set out at right angles to the body -Apoda: Caecilians; tropical group with a snakelike body, no limbs, little or no tail

Regarding the major groups of bony fishes: (a.) List each group by formal and common names and briefly describe each. (b.) When did lobe-finned fish evolve? Add this to your timeline. (c.) Which group shares the most recent ancestor with tetrapods?

a) 1. Ray-finned fishes (Class Actinopterygii) -parallel bony rays support and stiffen each fin -no muscles within the fins 2. Fleshy fin (CLass Sarcopterygii) -have pared fins that consist of a long fleshy muscular lobe -supported by central core of bones with fully articulated joints -Includes coelacanths (sC Actinistia, 2 spp) and lungfish (sC Dipnoi, 6spp) -almost certainly amphibian ancestors

Regarding the evolution of sharks: (a.) In what vertebrate class are sharks classified? (b.) When did this group first appear? Add this to your timeline. (c.) When did sharks become dominant in the seas? Add this to your timeline. (d.) What are some basic characteristics of this class of fish? (e.) Briefly describe teeth, the lateral line system, and reproduction in sharks. (f.) What other groups of cartilaginous fishes evolved after the Permian mass extinction?

a) Sharks are in Class Chondrichthyes b) Sharks and bony fish first appeared in the early Devonian, 400 MYA c) in the Carboniferous period (360-280 MYA) d) -cartilage skeleton calcified with granules of calcium carbonate e)- teeth evolved from rough scales on mouth's skin. -Sharks and bony fish have a lateral line system in which there is a series of sensory organs under the skin that detects changes in pressure waves. -reproduction: eggs are fertilized internally; most pups are born alive; sharks have long gestation periods (embryotic development) f)

Regarding the evolution of amphibians: (a.) Ancestors of modern amphibians moved onto land but had to overcome the challenges of moving to land part time. What were these challenges? (b.) What was one of the first tetrapods and what time period did it live based on the age of the rocks it was found? Mark this as an early amphibian on your timeline. (c.) What is Tiktaalik and why is it significant to the evolution of tetrapods? (d.) Document on your timeline the evolution of early tetrapods, which shows the rise and fall of amphibians.

a) They required adaptations-- legs to support body's weight, lungs to extract oxygen from air, redesigned heart and circulatory system to drive larger muscles, reproduction still in water to prevent egg drying, system to prevent whole body desiccation b)

Regarding bony fishes: (a.) When did bony fish fish first evolve? Add this to your timeline. (b.) Briefly describe features of bony fishes (including the skeleton, swim bladder, and operculum) that have helped make them the most diverse/dominant group today? Make labeled sketches where appropriate.

a) bony fish first evolved 400 MYA (same time as sharks) b) *skeleton: -heavy internal skeleton made completely of bone -swim bladder: gas-filled sac that allows bony fishes to regulate their buoyant density -operculum (gill cover): ventilates their gills so they don't have to keep swimming; flexing plate permits water pumping over gills and efficient bellows system when stationary.

Regarding the evolution of the jaw: (a.) When did jaws first evolve and in what groups of fish? Add these groups to your timeline.. (b.) Sketch and provide a written description for the evolution of the jaw.

a) in the late Silurian period; plactoderms and spiny fish (class Acanthodii) b) Jaws evolved from the anterior gill arches that were made of cartilage. Jaw was first seen in spiny fish which were extinct at close of Permian period. In Plactoderms the jaw was improved--upper jaw fused to the skull and the skull hinged at the shoulder.

The fact that monotremes lay eggs

is a plesiomorphic trait.