1. Nervous system (except Porifera)

2. Extracellular matrix w protein fibers

3. Cell junctions 

4. seuxal repro via sperm and egg 

5. hox gene (except Porifera) 

Classification: Tissue Types 

Presence (example) 

Absence (example)

Presence: Eumetazoa (all other phyla)

Absence: Parazoa 

Classification: Body Symmetry 
Radial (def and example)

Bilateral (def and example)

Radial: oral/aboral sides 

Radiata: Cniderians, Ctenophores 

Bilateral: dorsal, ventral, anterior, posterior 

Bilateria: all other phyla

Classification: Body Cavities 

Acoelomate (def and ex)

Pseudocoelomate (def and ex)

Coelomate (def and ex) 

Acoelomate: diploblastic, no body cavities 

Cnideria, platyhelminthes

Pseudocoelomate: triploblastic, mesoderm surrounds only  outside of endoderm

Rotiferia, Nemotodes 

Coelomate: triploblastic: Body cavities completely surrounded by mesoderm 

All others 

Classification: Embryonic Development 

Protostomes vs Deutrostomes

Cleavage 

Blastopore 

(examples) 

Protostomes: Spiral mitotic cleavage,

determinate cleavage

blastopore: mouth first 

(platy, rotifers, mollusks, annelids, nemotods, arthro)

Deuterostomes: Radial mitotic cleavage, 

indeterminate cleavage 

blastopore: anus first 

(echinoderms, chordates) 

osculum, spongocoel, ostia, choanocytes, amoebocytes, mesohyl, spicules 

Cnidaria anatomy 

hydra 

Obelia medusa 

hydra: mouth/anus, tentacles with cnidocytes, epidermis, mesoglea, gastrodermis, gastervascular cavity, nematocysts 

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Platyhelminthes anatomy

Planaria 

ocelli, auricles, pharynx, pharyngeal pouch 

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corona, mastax, digestive tract 

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Annelida anatomy 

earthworm 

metameres, pharynx, esophagus, aortic arches, seminal vesicles and receptacles, crop, gizzard, intestines, nephridia, anus 

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Porifera 

GI: 

Repro: 

Sponges
GI: Specialized for filter-feeding:                                                                                              ostiaàamoebocytesàspongocoelàchoanocytesàosculum

Mesohyl contains spongin fibers and spicules of CaCO2/silica
Repro: broadcast spawning or asexual budding 

(hydras, jellyfish, corals, anemones)

Diploblastic, acoelomate

GI: Gastrovascular cavity

NS: Nerve net

Repro: broadcast

Cnidocytes, nematocysts 

(comb jelly, bioluminescent)

Diploblastic, acoelomnate

GI: Complete gut – separate mouth and anus

NS: Nerve net

Repro: broadcast

(planaria, tapeworms, parasitic flukes)

Triploblastic, acoelomate

Cephalization: ocelli (photoreception) auricles (chemoreception) 

GI: Incomplete gut: ventral pharynx

GU: protonephridia, flame cells

NS: Nerve net + central ganglia, lateral/transverse nerve cords

Repro: sexual or asexual (hermaphrodic)

Proglottids segments, full of eggs breaks off

(platyhelminthes only) 

osmoregulation allows them to live in freshwater 

flame cell removes excess water

Triploblastic, pseudocoelomate

Cephalization: corona, mastax

Repro: parthenogenesis: save energy when low resources 
amictic diploid eggsàfemale

haploid eggsàmales fertilize other diploid eggs 

(gastropods, bivalves, cephalopods)

Triploblastic, coelomate

GI: complete w radula

GU: metanephridia able to reabsorb

NS: nerve cord

Circ: open circ w heart – hemolymph (O2 and nutrients)

Repro: external fertilization: trochophoreàveligeràadult 

(segmented worms, polychaeta, earthworms, leeches)

Segmented metameres

GI: complete unsegemented tract: pharynx, esophagus, crop, gizzard, intestines 

GU: metanephridia in each metamere

NS: cerebral ganglia, ventral nerve cord

Circ: aortic arches with blood and hemoglobin

Repro: sexual repro, internal fertilization, seminal vesicles 

(parasitic roundworms, c. elegans)

Triploblastic, pseudocoelomate, longitudinal muscles

GI: Complete w stylets (fangs)

GU: excretory cells and ducts

NS: simple brain w nerve cords

Repro: internal fertilization, vagina, ovaries, uterus 

(spiders, millipedes, centipedes, insects, crustaceans)

Exoskeleton segmented tagmata: head, thorax, abdomen

Cephalization: ommatidia, antennae

NS: Brain with ventral nerve ganglia

GI: mouth, crop, stomach, intestines, rectum

Circ: open circ system w hemolymph

Resp: tracheal system, book lungs

 GU: malphghian tubules for uric acid

Repro: sexual repro, female lays fertilized eggs 

(sea stars, urchins)

Radial symmetry, deuterostome

Water vascular system: tube feet, ampullae

GI: evertable stomach

GU: None, osmoconformer

NS:  nerve cords 

Chordata

(4 characteristics and subphyla)

(tunicates, lancelets, vertebrates)

Characteristics of chordate:

1.     Notochord

2.     Dorsal hollow nerve cord

3.     Pharyngeal slits

4.     Postanal tail

Urochordates: larval shows all 4 traits, as adults only slits

Cephalochordata: all four traits as adults

Vertebrata: three or four traits as adults

Myxini: Hagfish 

Cranium: enclose brain

Neural crest: embryonic cells that make jaw, cranium, peripheral nerves 

Chordata: 

Vertebrata 

Petromyzontida: Lampreys 

Vertebral column is bony 

Endoskeleton 

complex interal organs: liver 

Jaws: Gnathostomes and Chondrichthyes

resp

circ

NS

repro

Cartilaginous fish: sharks, rays 

placoid scales: calcified tissues, teeth evolved from scales 

resp: uncovered gill slits, continuous swimming 

Circ: 2-chambered heart, single circulation 

NS: lateral line to detect pressure waves

Repro: ovoviviparous vs viviparous 

Bony fish: Ostiechthyes

2 subclasses 

bony skeleton 

operculum gill flap 

swim bladder 

Actinopterygii: Ray finned (most successful) 

Resp: countercurrent exchange 

Actinistia: lobe finned: lungfish 

most similar to tetrapods, appendages, gills + lungs 

1.     Higher O2 content: evolution of lungs

2.     Lack of buoyancy: stronger limbs

3.     Variable habitats: more specialization in characteristics

4.     Variable temperature: ectothermic to generate own heat

5.     Limited water availability: conserving water, not needed for repro

Amphibians

resp 

circ

repro 

Require terrestrial and aquatic environments

 Resp: buccal pumping

Circ: 3 chambered heart, closed circulation, maintains BP

Repro: external fertilization, female lays eggs, eggsàtadpoleàadult

Frogs/toads (anurans)

Salamanders/newts (caudata): paedomorphosis: retain juvenile traits 

Critical innovations for life on land

Amnionic egg (membranes) 

Amnion: inner membrane

 Yolk sac: nutrients

Allantois: embryonic waste sac

Chorion: gas exchange for embryo 

Thoracic breathing: contract diaphragm to create (-)P

Keratinized skin: protection

Internal fertilization: no water required

 Kidneys: water conservation 

1.     Feathers – keep warm and enable flight

2.     Lightweight skeleton – hollow bones

3.     Air sacs – efficient breathing

4.     Reduction of organs: single ovary, no bladder 

1.     Mammary glands – secrete milk for newborns

2.     Hair – temperature regulation, endothermic

3.     Differentiated teeth – incisors, canines, molars

4.     Enlarged skull – large brain, single lower jaw, pinnae 

viviparous: placenta (mammals) 

ovoviviparous: yolk (birds, reptiles) 

Nervous systems: 

Nerve Net 

Cerebral Ganglia 

Subdivided Brain 

CNS/PNS

Nerve net: net of tissues control contractile muscles,

no brain

Cniderians, ctentophores (w nerve ring: echinoderms)

Cerebral Ganglia w cords: sensory touch, photo-chemoreception, motor swimming, feeding 

Platyhelminthes, molluska, annelids, nemotods

Subdivided brain: cephalization, coordinated sensory and motor 

Arthropods, celphelopods 

CNS/PNS: hindbrain: basic reflexes, midbrain: sensory, forebrain: cognition 

Chordata 

Circulatory system 

gastrovascular cavity 

open circulation 

closed circulation 

2-chambered, 3-chambered, 4-chambered hearts

gastrovascular cavity: single opening to outside, diffusion, cila promotes circulation 

cniderians, platyhelminthes

open circulation: hemolymph pumped by heart into body cavity 

arthropods, mollusks 

closed circulation: blood pumped by heart into vessels, BP

annelids, cephalopods, vertebra 

2-chambered heart: single circ with gills 

fish 

3-chambered heart: double circ, mixed blood 

amphibians, reptiles 

4-chambered heart: double circ (pulmonary and systemic) 

crocs, birds, mammals

Respiratory system 

diffusion 

tracheal system 

gills 

lungs: tidal breathing 

lungs: crosscurrent air sacs

diffusion: nutrients move across cells in body cavities 

cniderians, platy, rotofers, echinoderms 

diffusion through skin: only amphibians 

tracheal system: surface of exoskeleton

spiracles-->trachea-->trachioles (amphibians)

gills: buccal pumping, ram ventilation (fish)

lungs: tidal breathing: diaphragm -P (mammals)

crosscurrent air sacs: separate air quality (birds)