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Caterpillar feeding on host plant |
Phylum Porifera
Mostly marine, radially symmetrical or asymmetrical
Free-swimming larvae, sessile adults
Maintain internal water currents to obtain food
Intracellular digestion by archaeocytes
No nervous system or sensory organs, spongocoel
Phylum Cnidaria
Radially symmetrical
Sessile, sedentary, or slow
Tissue level of organization, saclike body plan
Oral & aboral ends, tentacles, nerve net, mouth
Aquatic, mostly marine, muscles for locomotion
Polyp & medusa
Jellyfish, corals, sea anemones, etc
Phylum Ctenophora also radially symmetrical
Protostomes
Phylum Platyhelminthes (flatworms)
Bilateral symmetry, head, protostome, 3 germ layers, cross section
Organ-system level of organization, free-living or parasitic
Anterior ganglia for "brain", sensory organs
Class Turbellaria--mostly free-living
Planarian
sac-like digestive system, ventral mouth, pharynx, intestine
eyespots & auricles
Class Trematoda (flukes)--endoparasitic
Class Monogenea (monogenetic flukes)--ectoparasitic
Class Cestoda (tapeworms)--endoparasitic
Phylum Nematoda (roundworms)
Found everywhere--aquatic, terrestrial, parasitic
Tube-within-a-tube digestive system: mouth, pharynx, intestine, rectum, anus
Ascaris lumbricoides--human intestinal roundworm
Phylum Annelida (segmented worms)
Segmentation, somites, cerebral ganglia for brain
Complete, unsegmented digestive system
Nephridia (kidneys) in each segment remove waste from blood
Some annelid species have trochophore larvae
Class Polychaeta--mostly marine
Class Oligochaeta
Earthworms
Add nutrients to soil
Mouth, pharynx, esophagus, crop, gizzard, intestine, anus
Class Hirudinida--leeches (ectoparasitic)
Phylum Mollusca
Protostome, spiral cleavage, unsegmented, organ systems, shell, foot
Trochophore larvae in many--relation to annelid development
Gastropods (snails, slugs, etc)
Bivalves (clams, mussels, etc)--2 shells, burrow or creeping locomotion w/ foot
Cephalopods (squid, octopi, etc)--predators, eyes, tentacles
Phylum Arthropoda
diversity & abundance, somites, jointed appendages, metamorphosis
horseshoe crabs, spiders, scorpions, crustaceans, insects, centipedes, millipedes, etc.
beneficial (pollinators) & harmful insects
Deuterostomes
Phylum Echinodermata
radial cleavage, spiny skin, water vascular system, bilateral larvae, radial adults
oral & aboral aspects
sea stars, brittle stars, sand dollars, sea urchins, sea cucumbers, crinoids
Phylum Hemichordata
Phylum Chordata
Notochord (develops into endoskeleton in vertebrates)
Dorsal hollow nerve cord
Predation prevalent, leading to highly developed nervous & sensory organs
Pharyngeal slits (develop into gills in many aquatic and amphibious species)
Paired appendages--fins, limbs, wings
Postanal tail, segmented myotomes
Subphylum Urochordata--tunicates
sea squirts
Subphylum Cephalochordata--lancelets
Amphioxus
Subphylum Vertebrata--vertebrates
The Fishes
Class Myxini (hagfishes)--jawless, feed on dead or dying animals
Class Petromyzontida (lampreys)--jawless, ectoparasitic
Larvae (ammocoetes) resemble Amphioxus
Class Chondrichthyes (cartilaginous fishes)--jaws
Sharks, rays, skates, chimaeras
Class Osteichthyes (bony fishes)--jaws
Bass, sunfish, perch, trout, salmon, tuna, catfish, etc.
Tetrapods
Early tetrapods, colonization of land, fins become legs, lungs
Class Amphibia
Can use land, but usually tied to water for reproduction
Ectothermic
Respiration: gills as larvae; lungs as adults
Salamanders, frogs, toads, caecilians
Amniotes
Class Reptilia
Shelled, amniotic egg
Extraembryonic membranes: amnion, chorion, allantois
Most species entirely terrestrial, ectothermic
Dry, scaly skin
Turtles, snakes, lizards, crocodiles, etc.
Class Aves (birds)
Descended from dinosaurs (reptiles), endothermic, feathers
Class Mammalia
Hair, endothermic, glands in skin
Opossums, moles, bats, humans, rabbits, rodents, dogs, deer, etc.