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
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