Animal Phylogenies

Biology 211 - Principles of Biology I

Phylum Echinodermata

Calcareous plate endoskeleton, complete digestive system, pentaradial adults, muscle and nervous tissue, water vascular system, sexual reproduction

Phylum Chordata

Pharyngeal slits/pouches, dorsal hollow nerve cord, notochord, and a post-anal tail

Subphylum Cephalochordata

Suspension feeders that filter small food particles using pharyngeal slits

Subphylum Urochordata

Filter feeders with incurrent and excurrent siphons, adults do not possess chordate characteristics

Subphylum Vertebrata

Pronounced cephalization, vertebral column enclosing nerve cord (replacing notochord function), 3-part brain, endoskeleton, paired sense organs, closed circulatory system

Jawless Fish

Hagfish and lampreys; lost vertebrae over time

Chondrichthyes

Sharks, rays, and skates; Cartilaginous skeleton, paired appendages, lost jaws, bones, and lungs

Ray-finned Fish

Gills (from pharyngeal slits) used in respiration, lungs used for swim bladder, notochord present in embryo

Lobed fins

2 pairs that articulate, support weight over short distances

Tetrapoda

Limbs evolved from fins, pelvis fused to vertebrae, no gill slits, pharyngeal clefts form inner ear

Amphibians

Eggs and larvae are aquatic, adults are terrestrial; undergo metamorphosis, external fertilization, gas permeable skin

Amniotes

Shelled egg (post-fertilization), extra-embryonic membranes, allows for development on land, includes reptiles (+bird), mammals

Function of the chorion

Gas exchange

Function of Allantois

Waste storage

Function of the Yolk sac

Nutrient transfer

Function of the Amnion

Fluid protecting embryo

Reptiles (Non-bird)

Ectothermic, scaly skin reduces water loss, egg incubation, temperature dependent sex determination

Birds

Feathers, reduced organ systems, keel on sternum, hollow bones, endothermic

Mammals

Mammary glands, internal incubation of young, ahir, diaphragm, specialized teeth

Monotremes

No placenta (egg-laying), no nipples; echidna and platypus

Marsupials

Embryo born undeveloped; most in Australia, one North American species (opossum)

Eutherians

Placental mammal

Class Trematoda

Ectoparasites or endoparasites, complex lifestyles for multiple hosts; flukes

Superphyla Lophotrochozoa

Triploblastic, bilateral symmetry, spiral and determinate cleavage, indirect development

Function of lophophore and which life stage is it found in

Feeding and respiration; adults

Function of trochophore and which life stage is it found in

Feeding and movement; larvae

Phylum Platyhelminthes

Acoelomate, no lohophore/triploblast, bilateral symmetry, cephalization, central nervous system, incomplete digestive system or none at all, parasitic or free living

Class Cestoda

Found in intestines of vertebrates, no digestive system, have a scolex; tapeworms

Scolex

Organ on head designed to attach to a host; has hooks and/or suckers

Phylum Annelida

True coelomates, are segmented, live in marine, freshwater, and damp terrestrial habitats

Subclass Oligochaeta

Earthworms

Subclass Hirudinea

Leeches (parasitic)

Phylum Mollusca

Triploblasts, mostly marine, some freshwater, generally separate sexes, six-part body plan

Six-part body plan of Mollusca

Foot, mantle, shell, visceral mass, gill, radula

Protostomes

Blastopore becomes mouth

Deuterostomes

Blastopore becomes anus

Lophotrochozoans

Protostomes

Ecdysozoans

Protostomes