Pre Chapter 21
1. Hexapods can be identified from other arthropods because they have the
characteristic 6 legs. Entognatha have internal mouthparts while Insecta have
external mouthparts and wings.
2. Ability to fly, lightweight exoskeleton, small size, readilydispersed eggs (well
protected), limited evaporation, dormancy in adverse conditions, continuing rabid
3. Insect exoskeleton is lightweight and more highly jointed to allow for movement.
The crustaceans’ exoskeleton is heavier. Mineral deposits provide rigidity in
crustaceans, but scleroproteins provide rigidity in insects.
Post Chapter 21
1. Foregut, midgut, hindgut. Fore mouth, esophagus, crop, gizzard. Mid stomach
and cecum. Hind intestines, rectum, anus.
2. Grasshopper tearing
3. Parasitoid: kill host. Hyperparasitism: parasite has a parasite.
4. The spiracles let air in, keep in water, and keep out debris. Then air travels
through the tracheae supported by taenidia, then air goes to the tracheoles in
individual cells, which is where gas exchange occurs.
5. Malphighean tubules and rectal glands. Rectal glands secrete Chloride, Sodium,
and water. Secrete uric acid.
6. Direct development: offspring are just like parents. Incomplete metamorphosis:
egg, nymph, and adult. Complete metamorphosis: egg, pupa, and adult.
7. Prothoracic gland secretes ecdysone. The Corpora Allata secretes juvenile
hormone. Juvenile hormone critically low ▯pupa. None ▯adult. Prothoracic gland
degenerates and ecdysis stops.
8. Estivation: summer. Hibernation: winter. Diapause: regardless of conditions.
9. Pheromones: attraction to other individuals/ communication. Sound production
and reception: mating. Tactile: tapping, stroking, grazing. Visual:
1. Chaetognatha: Have characteristics of deuterostomes and protostomes.
Deuterostomes have a welldeveloped coelom and a complete digestive system.
They share nucleotide sequences with ecdysozoans.
2. Their larval forms have bilateral symmetry. Advantage to pentaradial symmetry is
interaction with environment from all sides.
3. Five characteristics: pentaradial symmetry, calcareous spiny endoskeleton, dermal
branchiae, pedicellariae, water vascular system.
4. Water enters the madreporite, goes into the stone canal, goes into the ring canal,
enters the rays through the ray canals. Then the water is pushed out of the tube
foot as jet propulsion (inner end ampulla)
5. Respiration: dermal branchiae. Feeding: everts stomach through mouth.
Digestion: short esophagus, cardiac stomach, pyloric stomach and ceca, some
small intestine, anus inconspicuous. Excretory: through diffusion; excrete
ammonia. Reproduction: most dioecious, pair of gonads in each ray, ext.
fertilization in early summer, most freeswimming larvae. 6. Class Ophiuroidea: brittlestars have thinner limbs, lack pedicellariae. Class
Echinoidea: lack arms. Class Holothuroidea, sea cucumbers, elongated oralaboral
axis. Class Crinoidea: lack pedicellariae, sessile.
7. Echinoderms are important for research and we eat them.
1. Traditional classifications include para, poly, and monophyletic groupings.
Cladistics includes only monophyletic groupings.
2. Notochord: muscle attachment and endoskeleton, dorsal tubular nerve cord: brain
arises from it, postanal tail: greater movement, endostyle or thyroid helps with
metabolism and iodinated proteins—filter feeding, pharyngeal pouches or slits:
3. SubPhylum urochordata are chordates because their larval forms have the 5
hallmark characteristics even though their adult forms go through metamorphosis
and do not.
4. Amphioxus are interesting to zoologists because they still show the 5 hallmark
characteristics in the adult form. They are similar to vertebrates because they
show all 5, but dissimilar because they don’t have a 3 part brain. Amphioxus have
pharyngeal slits (filter feeding)—cilia beat to create water flow and bring food to
the siphon, the endostyle secretes mucous, mucous net collects food, rolled into
ball and engulfed. Closed circulatory system with no heart. Muscular contractions
push blood around.
5. All vertebrates share the cranium.
6. Musculoskeletal adaptations: exo and endoskeleton, better muscles for movement,
body size, myomeres V to W shaped. Physiological pharynx from filter feeding to
respiration, more developed digestive tract, liver and pancreas, chambered heart,
paired kidneys. New head, brain, and sensory systems: Forebrain, midbrain,
hindbrain; paired special sense organs; neural crest and ectodermal placodes.
7. Neural crest: cranium, pharyngeal slits, tooth dentine, cranial nerves, ganglia,
schwann cells, endocrine glands. Ectodermal placodes: olfactory epithelium, eye
lens, inner ear epithelium, mechano and electro receptors, some ganglia and
8. Garstrang hypothesized that some failed to metamorphose and gained gonads and
reproduced. Free swimming ancestral animals. It’s been rejected.
9. Urochordata is the closest living relative.
1. Fish aren’t monophyletic they don’t include tetrapods.
3. Hagfishes and Lampreys are in subphylum vertebrata because they have a
4. Gnathostomes have a jaw.
5. Aquatic vertebrate that has gills, fins, Wshaped Myomeres, they use swimming
for locomotion, and have a swim bladder for buoyancy.
6. Class Myxini: hagfishes, Class Petromyzontida: lampreys; keratinized teeth and
anticoagulant, Class Sarcopterygii: lobef