AP Biology, Chapter 33
Invertebrates [by clade]

SUMMARY
INTRODUCTION

PARAZOA
	Introduction
	Phylum Porifera: Sponges are sessile with porous bodies and choanocytes
		1. Identify the parts of a sponge (including the spongocoel, porocyte, epidermis, 
		choanocyte, mesohyl, amoebocyte, osculum, and spicule) and describe the function of 
		each.
			a. Lifestyle: sessile, immobile filter feeders
			b. Water circulation
				i. Epidermis seals outside
				ii. Flagellated choanocytes lining the spongocoel push water toward the 
				osculum
				iii. As water is sucked in the porocytes, the choanocytes filter suspended 
				particles
			c. Nutrition: amoebocytes distribute digested particles
			d. Structure
				i. Mesohyl contains protein matrix and spicules
				ii. Constructed and maintained by amoebocytes
			e. Reproduction
				i. Sexual: most are hermaphrodites
				ii. Asexual: regeneration

RADIATA
	Introduction
	Phylum Cnidaria: Cnidarians have radial symmetry, a gastrovascular cavity, and 
	cnidocytes
		2. List the characteristics of the phylum Cnidaria that distinguish it from the other animal 
		phyla. 
			a. Have muscle and nerve tissue, lack well-developed mesoderm
			b. Radially symmetrical; mouth but no anus
			c. Carnivores and detritovores: cnidocytes paralyze and attach to prey
			d. Prey digested in dead end gastrovascular cavity
			e. Reproduce sexually, by budding, and by regeneration
		3. Describe the two basic body plans in Cnidaria and their role in Cnidarian life cycles.
			a. Polyp
				i. Sessile, mouth up, surrounded by tentacles
				ii. Ex.: Hydra, sea anemone
			b. Mudusa
				i. Free-swimming, mouth down
				ii. Ex.: jellyfish
		4. List the three classes of Cnidaria and distinguish among them based on life cycle and 
		morphological characteristics.
			a. Class Hydrozoa: ex. Hydra; alternate polyp and medusa
			b. Class Scyphozoa; ex. jellyfish like Aurelia; dominant medusa
			c. Class Anthozoa: ex. anemones; polyps only
	Phylum Ctenophora: Comb jellies possess rows of ciliary plates and cohesive 
	colloblasts
		5. List the characteristics of the phylum Ctenophora that distinguish it from the other 
		animal phyla.
			a. "Comb-bearer"; eight rows of fused cilia for locomotion
			b. Two long tentacles have colloblasts for feeding on plankton

PROTOSTOMIA: LOPHOTROCOZOA
	Introduction
		6. Distinguish between the following pairs: acoelomates and coelomates, protostomes 
		and deuterostomes, and Lophotrochozoa and Ecdysozoa.
			a. Acoelomates lack a body cavity; coelomates have a body cavity surrounded by 
			mesoderm
			b. Protosomes have spiral determinate cleavage, schizocoely, and "first mouth"; 
			vs. radial, indeterminate, enterocoely, and "first anus"
			c. Ecdysozoa are the molting protostomes; Lophotrochozoa are the other 
			protostomes
	Phylum Platyhelminthes: Flatworms are dorsoventrally flattened acoelomates
		7. List the characteristics of the phylum Platyhelminthes that distinguish it from the other 
		animal phyla.
			a. Acoelomate without an anus
			b. Name means "flat worms"
			c. Both parasitic and free-living forms 
		8. Distinguish among the four classes of Platyhelminthes and give examples of each.
			a. Class Turbellaria
				i. Most marine, some freshwater, predators and scavengers; body 
				surface ciliated
				ii. Ex.: planaria
			b. Class Monogenea
				i. Parasites (flukes) with a simple life history, one egg  one adult
				ii. Aquatic ectoparasites
			c. Class Trematoda
				i. Vertebrate parasites with two suckers and  complex life histories
				ii. Schistosoma
			d. Class Cestoidea
				i. Scolex with suckers and hooks; proglottids are reproductive sections; 
				no digestive system
				ii. Tapeworms 
		9. Describe the generalized life cycle of a trematode and give an example of one fluke 
		that parasitizes humans.
			a. Life cycle
				i. Sexual reproduction in human, eggs shed in feces
				ii. Larvae infect snails
				iii. Asexual reproduction in snail, larvae released
				iv. Larvae penetrate skin of human
			b. Ex.: blood fluke
		10. Describe the generalized life cycle of a tapeworm.
			a. Proglottids packed with eggs break off, exit anus
			b. Contaminated feed infects pigs/cattle
			c. Larvae encyst in muscle
			d. Transferred to humans in undercooked meat
	Phylum Rotifera: Rotifers have jaws and a crown of cilia
		11. Describe unique features of rotifers that distinguish them from other 
		pseudocoelomates.
			a. Pseudocoelom: endoderm in a cavity, not covered by mesoderm
				i. Hydrostatic skeleton
				ii. Internal transport
			b. Mouth and anus
			c. "Wheel-bearer": curved rows of cilia around the mouth with grinding jaws
		12. Define parthenogenesis and describe alternative forms of rotifer reproduction.
			a. Parthenogenesis: haploid females  haploid females in favorable conditions
			b. Sexually in unfavorable
			
	The lophophorate phyla: Bryozoans, phoronids, and brachiopods are coelomates with 
	ciliated tentacles around their mouths
		13. Define lophophore and list three lophophorate phyla.
			a. Lophophore = horseshoe-shaped or circular fold with ciliated tentacles
			b. Phyla
				i. Bryozoans: "moss animals"; mostly marine; some build reefs
				ii. Phoronids: marine tube worms; up to 0.5 m
				iii. Brachiopods: lamp shells; marine, sessile filter feedesrs
	Phylum Nemertea: Proboscis worms are named for their prey-capturing apparatus
		14. List the distinguishing characteristics of the phylum Nemertea.
			a. Small coelom remnant operates the proboscis
			b. Mostly marine, free-swimming or burrowing
			c. Similar to flatworms except: have an anus, closed circulatory system
	Phylum Mollusca: Mollusks have a muscular foot, a visceral mass, and a mantle
		15. List the characteristics that distinguish the phylum Mollusca from the other animal 
		phyla.
			a. Soft-bodied, many with a CaCO3 shell
			b. Muscular foot for locomotion
			c. Visceral mass
			d. Mantle that secretes the shell and surrounds the mantle cavity
			e. Radula = rasping tongue
			f. Tufted, trochophore larva
		16. Describe how the basic body plan of a mollusk has been modified in the Bivalvia, 
		Cephalopoda, Gastropoda, and Polyplacophora.
			a. Bivalvia ("two shells", clams)
				i. Flattened shell with two halves
				ii. Head reduced (less cephalized, less mobile)
				iii. Most filter-feed through siphons
			b. Cephalopoda ("head foot", octopi)
				i. Highly cephalized, fast-moving predators
				ii. Best sense organs, most complex brain/behavior
				iii. Foot modified into tentacles
				iv. Only class with closed circulatory system
			c. Gastropoda ("stomach foot", snails and slugs)
				i. Asymmetrical body usually with a coiled shell
				ii. Torsion: anus on shoulder; more compact
				iii. Foot specialized for gliding
				iv. Moderately cephalized for slow movement
			d. Polyplacophora ("many plates", chitons)
				i. Shell in the form of eight dorsal plates
				ii. Less cephalized, slow moving grazers
	Phylum Annelida: Annelids are segmented worms
		17. List the characteristics that distinguish the phylum Annelida from the other animal 
		phyla.
			a. Body composed of ring-like segments
			b. Coelomates with closed circulatory system
			c. Well-differentiated digestive system: pharynx, crop, gizzard, intestine
			d. Metanephridia excrete nitrogen waste
			e. Hermaphrodites: eggs laid in mucus capsule made by clitellum
		18. Distinguish among the classes of Annelida and give examples of each.
			a. Oligochaeta ("few bristles", earthworms)
				i. Clitellum, few or no setae
				ii. Poorly cephalized
				iii. Burrow and eat soil, feces = castings
			b. Polychaeta ("many bristles", marine worms)
				i. Better cephalized, more active
				ii. Parapodia with chitinous setae
				iii. Mostly marine, some predatory
			c. Hirudinea ("leech", L.)
				i. Undivided coelom, suckers at both ends
				ii. No setae, body flattened
				iii. Predators and scavengers

PROTOSTOMIA: ECDYSOZOA
	Introduction
	Phylum Nematoda: Roundworms are nonsegmented pseudocoelomates covered by 
	touch cuticles
		19. List the characteristics of the phylum Nematoda that distinguish it from other 
		wormlike animals.
			a. Pseudocoelom for support and circulation
			b. Parasitic and free-living forms
			c. Unsegmented, relatively uncephalized, tapered body
			d. Collagen-chitin cuticle; grows by molting (ecdysis)
		20. Give examples of both parasitic and free-living species of nematodes.
			a. Parasitic
				i. Trichinella  forms cysts in skeletal muscle
				ii. Ascaris are found in the digestive systems of farm animals
				iii. Dog heartworm
				iv. River blindness
				v. Many plant diseases
			b. Free-living
				i. Common in soils; important decomposers
				ii. Caenorhabditis elegans is an important research system 
	Phylum Arthropoda: Arthropods are segmented coelomates with exoskeletons and 
	jointed appendages 
		21. List the characteristics of arthropods that distinguish them from the other animal 
		phyla.
			a. Segmented, hard exoskeleton, specialized jointed appendages
			b. Grows by molting (ecdysis)
			c. Well-developed sensory structures; most are well-cephalized
			d. Open circulatory system
			e. Extremely diverse; 1018 individuals
		22. Describe advantages and disadvantages of an exoskeleton.
			a. Advantages: protection, stiffer levers, hard tool surfaces
			b. Disadvantages
				i. Most have specialized appendage for each job
				ii. Locked in; must molt before enlargement, vulnerable at that time
		23. Define and distinguish between the major independent arthropod lines of evolution 
		represented by: Trilobita, Chelicerata, Crustacea, Uniramia.
			a. Trilobita
				i. All extinct
				ii. Head, thorax, and tail; branched appendages; calcite lenses
			b. Chelicerata
				i. No mandibles, clawlike chelicerae for feeding
					.Fangs in spiders
					.Pincers in scorpions
				ii. Cephalothorax and abdomen
				iii. No antennae
			c. Crustacea
				i. Mandibles, two pairs of antennae, compound eyes
				ii. Branched (biramous) appendages
				iii. Includes decapods, copepods, and isopods
			d. Uniramia
				i. Mandibles, one pair of antennae, compound eyes
				ii. Unbranched (uniramous) appendages
				iii. Includes centipedes, millipedes, and insects
				iv. Both complete and incomplete metamorphosis
		24. Describe the different views regarding the relationship between arthropods and 
		annelids.
			a. Arthropods from annelids
			b. Or, both from a segmented common ancestor
			c. Or, evolved segmentation independently; Lophotrochozoa vs. Ecdysozoa
		25. Describe the basic mechanism for the development of segmented bodies.
			a. Embryo mesoderm forms blocks (somites) that map the embryo 

DEUTEROSTOMIA
	Introduction
	Phylum Echinodermata: Echinoderms have a water vascular system and secondary 
	radial symmetry
		26. List the characteristics of echinoderms that distinguish them from other animal phyla.
			a. Deuterostomes
			b. Bilateral symmetry in larvae, radial in adult
			c. Molecular data puts them in Bilateria
			d. Water vascular system, use suction in tube feet to move and feed
			e. Endoskeleton of calcareous plates
		27. Distinguish among the five classes of echinoderms and give examples of each.
			a. Asteroidea
				i. Arms with tube feet
				ii. Predators: grip and pull clams open, evert stomach
			b. Ophiuroidea
				i. Brittle stars; snake-like segmented arms
				ii. Tube feet lack suckers
			c. Echinoidea
				i. Sea urchins and sand dollars
				ii. Endoskeleton fused into a rounded test
				iii. Movable spines on pivots for protection, burrowing
			d. Crinoidea
				i. Sessile sea lilies and slow-moving feather stars
				ii. 500 mya fossils look like today's
			e. Holothuroidea
				i. Sea cucumbers lack spines; have reduced endoskeleton
				ii. Superficial pentaradial symmetry and tube fett
	Phylum Chordata: The chordates include two invertebrate subphyla and all 
	vertebrates
		28. Explain why the phylum Chordata is included in a chapter on invertebrates.
			a. Urochordates and cephalochordates have no backbone
		29. Describe the evolutionary relationships between echinoderms and chordates.
			a. They share a deuterostome ancestor
			b. Diverged 500 mya