Invertebrates

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Radial canal

Ring

canal

Central disk

Digestive glands

Slide 100

Sea Stars

Sea stars, class Asteroidea, have multiple arms radiating from a central disk.

The undersurfaces of the arms bear tube feet, each of which can act like a suction disk.

Sea stars can regrow lost arms - regeneration.

Slide 101

Echinoderms

(a) A sea star (class Asteroidea)

(c) A sea urchin (class Echinoidea)

(e) A sea cucumber (class Holothuroidea)

(b) A brittle star (class Ophiuroidea)

(d) A feather star (class Crinoidea)

(f) A sea daisy (class Concentricycloidea)

Slide 102

Sea urchins and sand dollars have no arms

but have five rows of tube feet

Slide 103

Sea Cucumbers

Sea cucumbers lack spines, have a very reduced endoskeleton, and do not look much like other echinoderms.

Sea cucumbers have five rows of tube feet; some of these are developed as feeding tentacles.

Slide 104

Fig. 33-40e

Echinoderm - A sea cucumber

Slide 105

Chordates

Phylum Chordata consists of two subphyla of invertebrates as well as hagfishes and vertebrates.

Chordates share many features of embryonic development with echinoderms, but have evolved separately for at least 500 million years.

Slide 106

Animal Phyla

Slide 107

You should now be able to:

Describe how a sponge feeds and digests its food.

List the characteristics of the phylum Cnidaria that distinguish it from other animal phyla.

List the four classes of Cnidaria and distinguish among them based on life cycle morphology.

List the characteristics of Platyhelminthes and distinguish among the four classes.

Describe the features of molluscs and distinguish among the four classes.

Slide 108

6. Describe the features of annelids and distinguish among the three classes.

7. List the characteristics of nematodes that distinguish them from other wormlike animals.

8. List three features that account for the success of arthropods.

Define and distinguish among the four major arthropod lineages.

Describe the developmental similarities between echinoderms and chordates.