Animals

Question 1

Sponge

Answer 1

Organizational Grade.
No true tissues.
Cells retains great deal of autonomy.
Body Form.
Inner LayerFeeding layerlined with choanocytes.
Choanocytes.
Middle LayerMesohylSpongin, spicules, amoebocytes, archeocytes.
Spongin.
Spicules.
Amoebocytes.
Archeocytes.
Outer LayerPinacoderm, pores.
Pinacoderm.
Pores.
Basic Life History.
Sessile.
Filter Feeding.
Asexual reproduction.
Fragmentation.
Gemmules for overwintering.
Sexual reproduction.
Cross fertilization.
Ciliated larvae.
Occurrence.
Mostly marine.
Many deep-water.
Some freshwater.
Importance.
Economicbath sponges.
Biologicalnature of multicellularity and self-non-self recognition.

Question 2

Cnidarian

Answer 2

Organizational Grade
True Tissues Diploblastic.
-some cells with multiple functions, e.g., epitheliomuscular cells.
-nerve net and decentralized nervous system.
A few genuine organs (gonads).
Body Form
Gastrodermis.
Blind pouch.
Gastrovascular.
Extracellular and intracellular digestion.
Mesoglea.
Fluid filled.
A few cells in some, but no tissues.
Epidermis.
Cnidocytes.
Gastrodermal and/or epidermal.
Nematocystsstinging cells.
Gonadsgastrodermal or epidermal.
Body Types.
Medusafree-swimming (mostly), sexually mature.
Polypsessile (mostly), asexual reproduction by budding.
-colonialism common.
Basic Life History
Generalized life cycle.
Polyp that buds medusa.
Medusae reproduce sexually.
Zygote develops into polyp.
Other groups with just polyp or medusa stage.
Predatory.
Occurrence
Marine with few freshwater and parasitic species.
Coral reefs.
Reef types.
Reef distribution.

Question 3

Flatworm

Answer 3

Organizational Grade
True Tissues Triploblastic, acoelomate, spiral cleavage.
Organs and organ systems.
Centralized nerve system.
-Anterior ganglion.
-Longitudinal nerve cords and transverse commissures (ladder-like).
Body Form
Gastrodermis.
Blind pouch or absent.
Gastrovascular.
Extracellular and intracellular digestion.
Mesoderm.
Parenchyma.
Complex musculature.
Epidermis.
Cellular or syncytial.
Can be ciliated.
Basic Life History
Adults generally hermaphroditic.
Free-living forms with short-lived larvae and fairly direct development.
Parasitic forms generally with 1 or more larval stages and complex life cycles.
Turbellarians.
Few freshwater species (planarians); many marine species.
Scavengers and predators.
Monogeneans.
Ectoparasitic.
Mostly on fish gills, fins, scales, and skin.
1-host life cycle.
Cestodes (tapeworms).
Gut absentabsorb nutrients from host digesta.
Endoparasitic (adults in gut of definitive host).
Larval development in invertebrates and/or vertebrates.
Trematodes (flukes).
Endoparasitic (adults in many different places in definitive host, depending on species).
1st intermediate host usually a mollusk.
-fluke undergoes asexual reproduction.
-cercaria stage shed and infects next host.
2nd intermediate host highly variable (vertebrate, invertebrate, plant, or absent).
-metacercariae develop.
-infective to definitive host.
Importance
Libbie Hyman.
Monogenes and cultured fish mortality.
Tapeworms and human/animal health.
Trematodes and human/animal health.

Question 4

Nematode

Answer 4

Organizational Grade.
Triploblastic; Pseudocoelomate; cleavage pattern unique.
Eutely in some species.
Complete gut.
Body Form.
Linear and tubular.
Semi-rigid cuticle.
Longitudinal muscles only.
Hydrostatic pressure.
S-shaped movement.
Basic Life History.
Highly varied.
Gonochoristic.
Sexual dimorphism.
Chemical signaling among mates.
Occurrence.
All habitats.
Soil and marine sediments probably with most species.
Parasitic forms of enormous significance.
Importance.
Parasites of humans, livestock, companion animals, and crops.
Dirofilaria, Ascaris, Meloidogyne, Hookworms (Ancylostoma; Necator), Whipworm (Trichuris).

Question 5

Annelida

Answer 5

Organizational Grade.
Triploblastic; Eucoelomate; Protostome.
Segmentation; some tagmatism.
Body Form.
Linear and tubular.
Longitudinal and circular muscles.
Segmented organ system except for gut.
Dorsal and ventral blood vessels—closed circulatory system.
Ventral nerve cord.
Three major groups:
Oligochaetesearthworms and relatives; few setae; clitellum; no parapodia.
Hirudinealeeches; no setae, clitellum; no parapodia; posterior sucker.
Polychaetesmany setae; no clitellum; parapodia; highly diverse.
Basic Life History.
Highly varied.
Hermaphroditic or gonochoristic.
Trochophore larva or not.
Occurrence.
All habitats.
Soil and marine sediments probably with most species.
Very few parasitic or commensal species.
Importance.
Varied ecological roles in marine sediments.
Earthworms and soil healthintroduced species.
Leeches and medicine.

Question 6

Mollusca

Answer 6

Organizational Grade.
Triploblastic; Eucoelomate; Protostome.
Coelom reduced to sac around hearthemocoel.
Open circulatory system.
Body Form.
Generalized Ancestral Mollusk.
-Dorsal shell; Secreted by dorsal mantle tissue.
-Ventral foot; muscular; creeping locomotion.
-Anterior head; radula.
-Posterior mantle cavity; gills, anus, nephridiopore.
Modifications in modern forms.
Monoplacophorashell flat; foot flat, locomotion.
Polyplacophorashell in 8 plates; foot flat, locomotion.
Scaphopodashell as elongate cone; foot shovel-shaped, burrowing.
Gastropodashell varied (helical & spiral); foot flat, locomotion.
Bivalviashell in 2 hinged (dorsal) valves (lateral); foot tongue shaped, burrowing.
Cephalopodashell reduced, absent, or chambered; foot as arms and tentacles.
Basic Life History.
Highly varied.
Gonochoristic or hermaphroditic.
Aquatic and terrestrial forms with direct development.
Marine forms often with larval stages (pelagic).
Occurrence.
All habitats.
Marine forms most diverse.
Freshwater snails, bivalves.
Terrestrial snails and slugs.
Importance.
Gigantic fossil record, oh my goodness.
Intermediate hosts to trematodes of human and animal health significance.
Foodall the rough and tough tasty tubes and the squishy salty snotty slickery goo-balls.