What function do the red whorls of this organism have? Figure 33.1 What function do the red whorls of this organism have?

Calcarea and Silicea ANCESTRAL PROTIST Cnidaria Common ancestor of Fig. 33-2 Review of Animal Phylogeny Calcarea and Silicea ANCESTRAL PROTIST Cnidaria Common ancestor of all animals Lophotrochozoa Eumetazoa Ecdysozoa Figure 33.2 Review of animal phylogeny Bilateria Deuterostomia

Fig. 33-3-1 Invertebrate Diversity Calcarea and Silicea (5,500 species) Placozoa (1 species) 0.5 mm A sponge Cnidaria (10,000 species) A placozoan (LM) Ctenophora (100 species) A jelly Acoela (400 species) A ctenophore, or comb jelly 1.5 mm Acoel flatworms (LM) LOPHOTROCHOZOANS Figure 33.3 For the Discovery Video Invertebrates, go to Animation and Video Files. Platyhelminthes (20,000 species) Rotifera (1,800 species) A marine flatworm A rotifer (LM) Ectoprocta (4,500 species) Brachiopoda (335 species) Ectoprocts A brachiopod

Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Fig. 33-UN1 Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

Anatomy of a Sponge Choanocyte Osculum Amoebocyte Food particles in mucus Flagellum Choanocyte Choanocyte Collar Osculum Azure vase sponge (Callyspongia plicifera) Spongocoel Phagocytosis of food particles Amoebocyte Pore Spicules Figure 33.4 Anatomy of a sponge Epidermis Water flow Amoebocytes Mesohyl

Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Fig. 33-UN2 Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

Mouth/anus Tentacle Polyp Medusa Gastrovascular cavity Gastrodermis Polyp and medusa forms of cnidarians Mouth/anus Tentacle Polyp Medusa Gastrovascular cavity Gastrodermis Mesoglea Body stalk Epidermis Figure 33.5 Polyp and medusa forms of cnidarians Tentacle Mouth/anus

Tentacle Cuticle of prey Thread Nematocyst “Trigger” Thread discharges A cnidocyte of a hydra Tentacle Cuticle of prey Thread Nematocyst “Trigger” Figure 33.6 A cnidocyte of a hydra Thread discharges Thread (coiled) Cnidocyte

Table 33-1

(a) Colonial polyps (class Hydrozoa) Fig. 33-7 Cnidarians (b) Jellies (class Scyphozoa) (c) Sea wasp (class Cubozoa) (d) Sea anemone (class Anthozoa) Figure 33.7 Cnidarians (a) Colonial polyps (class Hydrozoa)

Reproductive polyp Feeding polyp Medusa bud Gonad Medusa Egg Sperm Fig. 33-8-3 Reproductive polyp Feeding polyp Medusa bud MEIOSIS Gonad Medusa Egg Sperm SEXUAL REPRODUCTION ASEXUAL REPRODUCTION (BUDDING) Portion of a colony of polyps FERTILIZATION Figure 33.8 The life cycle of the hydrozoan Obelia Zygote 1 mm Developing polyp Planula (larva) Key Mature polyp Haploid (n) Diploid (2n)

Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Fig. 33-UN3 Lophotrochozoa includes the flatworms, rotifers, ectoprocts, brachiopods, molluscs, and annelids Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

Fig. 33-9 A marine flatworm (class Turbellaria) Figure 33.9 A marine flatworm (class Turbellaria)

Pharynx Gastrovascular cavity Mouth Eyespots Ganglia Anatomy of a planarian Pharynx Gastrovascular cavity Mouth Figure 33.10 Anatomy of a planarian, a turbellarian Eyespots Ganglia Ventral nerve cords

Male Human host Female Motile larva Ciliated larva Snail host Fig. 33-11 The life cycle of a blood fluke. Like many trematodes, it is a parasite. Male Human host Female 1 mm Figure 33.11 The life cycle of a blood fluke (Schistosoma mansoni), a trematode Motile larva Ciliated larva Snail host

reproductive structures Fig. 33-12 Anatomy of a tapeworm 200 µm Proglottids with reproductive structures Hooks Sucker Figure 33.12 Anatomy of a tapeworm Scolex

Jaws Crown of cilia Anus Stomach 0.1 mm Fig. 33-13 A rotifer Figure 33.13 A rotifer Anus Stomach 0.1 mm

(a) Ectoproct (sea mat) (b) Brachiopods Fig. 33-14 Lophophore Lophophore Figure 33.14 Lophophorates (a) Ectoproct (sea mat) (b) Brachiopods

Nephridium Visceral mass Heart Coelom Intestine Gonads Mantle Stomach Fig. 33-15 Basic Body plan of a Mollusc Nephridium Visceral mass Heart Coelom Intestine Gonads Mantle Stomach Mantle cavity Shell Mouth Radula Anus Gill Figure 33.15 The basic body plan of a mollusc Radula Mouth Nerve cords Foot Esophagus

Fig. 33-16 A chiton Figure 33.16 A chiton

Gastropods (a) A land snail Figure 33.17 Gastropods (b) A sea slug

Mantle cavity Stomach Intestine Anus Mouth Torsion - causes the animal’s anus and mantle to end up above its head. Mantle cavity Stomach Intestine Anus Mouth Figure 33.18 The results of torsion in a gastropod

Bivalve Figure 33.19 A bivalve

Clam Anatomy Coelom Hinge area Mantle Gut Heart Adductor muscle Digestive gland Anus Mouth Excurrent siphon Figure 33.20 Anatomy of a clam Shell Water flow Palp Foot Incurrent siphon Mantle cavity Gonad Gill

Cephalopods Octopus Squid Figure 33.21 Cephalopods Chambered nautilus

Annelid: Earthworm Cuticle Septum (partition between segments) Epidermis Coelom Circular muscle Metanephridium Longitudinal muscle Anus Dorsal vessel Chaetae Intestine Fused nerve cords Ventral vessel Nephrostome Metanephridium Clitellum Figure 33.22 Anatomy of an earthworm, an oligochaete Esophagus Crop Giant Australian earthworm Pharynx Intestine Cerebral ganglia Gizzard Mouth Ventral nerve cord with segmental ganglia Subpharyngeal ganglion Blood vessels

Leech Figure 33.24 A leech

Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Fig. 33-UN4 Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

A free-living nematode - round worm Figure 33.25 A free-living nematode (colorized SEM) 25 µm

Juveniles of the parasitic nematode Trichinella spiralis encysted in human muscle tissue Encysted juveniles Muscle tissue Figure 33.26 Juveniles of the parasitic nematode Trichinella spiralis encysted in human muscle tissue (LM)

trilobite fossil Figure 33.27 A trilobite fossil

Arthropod External Anatomy Cephalothorax Abdomen Antennae (sensory reception) Thorax Head Swimming appendages (one pair located under each abdominal segment) Figure 33.29 External anatomy of an arthropod Walking legs Pincer (defense) Mouthparts (feeding)

Horseshoe crabs Figure 33.30 Horseshoe crabs (Limulus polyphemus)

Arachnids Scorpion Dust mite Web-building spider 50 µm Figure 33.31 Arachnids Web-building spider

Anatomy of a spider Stomach Intestine Heart Brain Digestive gland Eyes Ovary Poison gland Figure 33.32 Anatomy of a spider Book lung Anus Gonopore (exit for eggs) Chelicera Pedipalp Spinnerets Sperm receptacle Silk gland

millipede Figure 33.33 A millipede

Centipedes, class Chilopoda, are carnivores Centipedes, class Chilopoda, are carnivores. They have one pair of legs per trunk segment Figure 33.34 A centipede

Anatomy of a grasshopper, an insect Abdomen Thorax Head Compound eye Antennae Heart Cerebral ganglion Dorsal artery Crop Anus Vagina Figure 33.35 Anatomy of a grasshopper, an insect Malpighian tubules Ovary Tracheal tubes Mouthparts Nerve cords

Metamorphosis of a butterfly (a) Larva (caterpillar) (b) Pupa (c) Later-stage pupa Figure 33.36 Metamorphosis of a butterfly (d) Emerging adult (e) Adult

Insect diversity Figure 33.37 Insect diversity

Crustaceans (a) Ghost crab (b) Krill (c) Barnacles Figure 33.38 Crustaceans (b) Krill (c) Barnacles

Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia Fig. 33-UN5 Calcarea and Silicea Cnidaria Lophotrochozoa Ecdysozoa Deuterostomia

Anatomy of a sea star, an echinoderm Stomach Anus Spine Gills Central disk Digestive glands Madreporite Radial nerve Figure 33.39 Anatomy of a sea star, an echinoderm Gonads Ring canal Ampulla Podium Radial canal Tube feet

Echinoderms Figure 33.40 Echinoderms (a) A sea star (class Asteroidea) (b) A brittle star (class Ophiuroidea) (c) A sea urchin (class Echinoidea) (d) A feather star (class Crinoidea) Figure 33.40 Echinoderms (e) A sea cucumber (class Holothuroidea) (f) A sea daisy (class Concentricycloidea)

Animal Phyla

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.

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.