Kingdom AnimaliaInvertebrates

All animal phyla except Phylum Chordata (the chordates)

97% of animals are invertebrates

Review of animal phylogeny

Parazoa: Phylum Porifera

No Embryonic Tissues Asymmetrical Mostly Marine

Sponges are filter feeders

Choanocyte : specialized feeding cells

Skeletal fibers:Spicules- calcium carbonate or silicacollagen protein: spongin

Sponges

Group Radiata• Radial Symmetry

• Diploblastic

• Phylum Cnidaria

• Phylum Ctenophora

Phylum Cnidaria

• Jellyfish, hydras, sea anemones, corals

• Exist as polyp or medusa body form

• Gastrovascular cavity with single opening

Figure 33.4 Polyp and medusa forms of cnidarians

Figure 33.7 The life cycle of the hydrozoan Obelia (Layer 3)

Cnidaria have unique cells called cnidocytes

Some cnidocytes contain stinging capsules called nematocysts

Table 33.1 Classes of Phylum Cnidaria

Classes of CnidariaHydrozoa

Anthozoa

Scyphozoa

Phylum Ctenophora

• Comb jellies• Only 100 spp.• Rows of cilia

Group Bilateria

• Bilateral symmetry• Triploblastic• Protostomic or

Deuterostomic

Protostomia- Group 1 Lophotrochozoa:

• Based on new molecular data

• Includes acoelomates, Phylum Platyheminthes

• Includes psuedocoelomates, Phyla Rotifera

• Includes old Lophophorates Phyla Bryozoa, Phoronida, Brachiopoda

• Includes old Protostomia, Phyla Mollusca, Annelida

Phylum Platyhelminthes – flatworms

• Acoelomate• Free-living and

parasitic species• Marine and freshwater• Mesoderm--> organs,

organ systems, muscle tissue

• Gastrovascular cavity with one opening

Table 33.2 Classes of Phylum Platyhelminthes

Class Turbellaria: Planarians

Class Trematoda: Flukes

Child with schistosomiasis

Class Cestoidea: Tapeworms

Tapeworms have no digestive track, absorbs food from host

Phylum Rotifera

• common, usu. freshwater microscopic

• smaller than some protists!• pseudoceol is hydrostatic skeleton• complete gut

Lophophorate Phlya• Phyla Bryozoa, Phoronida, Brachiopoda• True coelomates• U-shaped gut• Circular/U-shaped ridge bearing ciliated tentacles (lophophore)

Phylum Mollusca: snails, clams, squid, octopi

• Unsegmented bodies

• Body made of foot, visceral mass, and mantle

• Feed using radula (most)

• Shell secreted by mantle (most)

Basic Body Plan of a Mollusk

Table 33.3 Major Classes of Phylum Mollusca

Class Gastropoda• Snails, slugs, abalones• Torsion• Herbivores or predators

Class Bivalia• Scallops, clams,

mussels, oysters• Shell divided into 2

halves• Filter feeders

Class Cephlapoda

• Squids, octopus, nautilus

• largest, fastest, smartest inverts

• Reduced and internal shell

• advanced nervous system – learning

Phylum Annelida

• Segmented: series of repeating segments– controlled by separate

muscles– evolutionary important

for movement• hydrostatic skeleton• closed circulatory system• Cerebral ganglia• excretory organs –

nephridia

Table 33.4 Classes of Phylum Annelida

Annelids

Oligochaeta Polychaeta

Hirudinea

Protostomia-Group 2Ecdysozoa

• Animals that molt• Phyla Nematoda and

Arthropoda

QuickTime™ and aPhoto - JPEG decompressor

are needed to see this picture.

Phylum Nematoda• Roundworms• Pseudocoelomate• Thin cuticle• Complete digestive tract

Some Nematodes are parasiticTrichinella: trichinosis in humans

Ascaris in pig guts

Heartworms in a dog

Hookworms and pinworms can burrow through the skin

Figure 33.26 External anatomy of an arthropod

Phylum Arthropoda

• Insecta, Arachnida, Crustacea

• Exoskeleton made of

chitin and protein• Jointed appendages• Body segments: head,

thorax, abdomen

Table 33.5 Some Major Arthropod Classes

Trilobites

• Jointed appendages, very diverse

• Once dominant • Closest living

relative: horseshoe crab

Horseshoe crabs: a living fossil (a chelicerate)

Class Arachnida

• Spiders, scorpions, mites• 2 body regions

– 2 pairs of appendages on head (feeding)

– 4 pairs of legs on cephalothorax

• Many inject digestive enzymes

• Tracheae or book lungs• Simple eyes (often

multiple)

Class Diplopoda & Chilopoda

• Millipedes – 2 pairs of legs/segment

• Centipedes– 1 pair of legs/segment– Poison claws for

paralyzing prey

Class Insecta

•At least 1.5 million species

•3 regions, 1 pair of antennae on head, 3 pairs of legs on thorax, usu. 2 (1) pairs of wings

•Tracheae takes air to all parts of body

Table 33.6 Some Major orders of Insects (Anoplura-Dermaptera)

Table 33.6 Some Major orders of Insects (Diptera-Hymenoptera)

Table 33.6 Some Major orders of Insects (Isoptera-Odonata)

Table 33.6 Some Major orders of Insects (Orthoptera-Trichoptera)

Insects grow by metamorphosis

Complete metamorphosis

Class Crustacea• decapods (crabs,

shrimp, crayfish), isopods, amphipods, copepods

• most aquatic, marine• 3 body regions (fused

segments)• Multiple appendages• carapace, gills

Crustacean

pictures

Phylum Echinodermata• Deuterostomes• Sea stars, sea urchins,

brittle stars, sea lilly, sea cucumbers

• Radial symmetryQuickTime™ and aGIF decompressor

are needed to see this picture.

Echinoderms have a water vascular system including tube feet which function

in movement and feeding

Echinoderms have an endoskeleton of calcareous plates

Table 33.7 Animal phyla