-
porifera
- sponges
- basal
- lack true tissues
- suspension feeders
- choanocytes - engulf food particles; similarities between choanocytes and choanoflagellates
- mesohyl separates cell layers - gas exchange and waste removal occur by diffusion
- amoebocytes - everything, variety of functions
- hermaphrodites
-
cnidarians
- true tissues
- hydras, corals, jellies
- diploblastic, radial
- gastrovascular cavity
- sessile polyp; motile medusa
- cnidocytes contain cnidae (organelles); nematocysts - "stinging" cnidae
- no brain, noncentralized nerve net
-
lophotrochozoans
- platyhelminthes
- lophophores (ectoprocts and brachiopods)
- molluscs
- annelids
-
platyhelminthes
- flatworms
- triploblastic
- acoelomates
- diffusion
- protonephridia - network of tubules with flame bulbs; pull liquid through branched ducts to outside
- free-living species - move by cilia; ganglia; predators, scavengers; move by cilia and mucus
- parasitic species - tough covering and suckers; lots of reproductive organs; ex. tremadoes, tapeworms
-
ectoprocts and brachiopod similarities:
- u-shaped alimentary canal
- absence of a distinct head
- sessile
- true coelom completely lined by mesoderm
-
ectoprocts
- bryozoans
- colony encased in exoskeleton with pores
- lophophores (cilia crown)
- reef builders
-
brachiopods
- ex lamp shells
- two halves of each shell are dorsal and ventral
- marin
- attached to seafloor by a stalk
-
molluscs
- majority are marine
- all are soft-bodied
- many secrete a protective shell of calcium carbonate
- coelomates
- trochophore - ciliated larval stage
- 3 parts - foot, visceral mass, mantle
- radula scrapes up food
- chitons, gastropods, bivalves, cephalopods
-
chitons (mollusca)
- shell composed of eight dorsal plates
- body itself is unsegmented
- marine
-
gastropods
- developmental process known as torsion - visceral mass rotates 180 degrees, anus ends up above mouth
- distinct head with eyes at the tips of tentacles
- often leave a trail of slime
- snails
-
bivalves (mollusca)
- aquatic
- clams, oysters, mussels, scallops
- hinged shell; powerful adductor muscles
- no distinct head
- no radula
- suspension feeders
- sedentary
-
cephalopods (mollusca)
- marine predators with tentacles and beak-like jaws
- poison
- foot --> excurrent siphon/part of tentacles
- shell is generally reduced, internal, missing
- chamber nautiluses - only living cephalopod with an external shell
- complex brain
- first - close circulatory system
-
annelids
- segmented worms
- coelomates
- polychates, oligochates
-
polychaetes (annelida)
- each segment has a pair of parapodia - has numerous chitae (chitin bristles), supplied with blood vessels and function as gills
- mostly marine
- many live in tubes
-
oligochaetes (annelida)
- sparse chaetae
- earthworms - alimentary canal, soil, hermaphrodites or cross-fertilization
- leeches - suck blood by attaching temporarily
-
ecdysozoans
- shed a tough external coat (cuticle)
- molt (ecdysis)
- nematodes, arthropods, chelicerates, myriapods, hexapoda, crustaceans
-
nematoda
- roundworms
- tapering at ends
- alimentary canal
- lack a circulatory system
- pseudocoelomate
- muscles are longtitudinal; contraction produces a thrashing movement
- play impt role in decomposition and nutrient recycling
- humans are host to over 50 nematode parasites
-
arthropods: origins
- body plan - segmented body, hard exoskeleton, jointed appendages
- segments tended to fuse together and became fewer
- appendages became specialized for a variety of functions
- two unusual hox genes, both of which influence segmentation
-
arthropods: general characteristics
- appendages (modified)
- jointed and comes in pairs
- cuticle
- open circulatory system - hemolymph
- coelomates (reduced coelom; hemocoel is main body cavity)
- specialized gas exchange organs
- chelicerates (arachnids), myriapods, hexapoda, curstaceans
-
chelicerates
- chelicerae (clawlike feeding appendages)
- lack antennae
- simple eyes
- arachnids - the bulk of modern chelicerates
-
arachnids
- scorpions, spiders, ticks, mites
- cephalothorax (6 pairs of appendages)
- pedipalps - appendages that function in sensing, feeding, reproduction
- gas exchange carried out by book lungs
-
myriapods
- terrestrial
- pair of antennae
- three pairs of appendages modified as mouth parts, mandibles
- millipedes - herbivores, each segment has 2 pairs of legs
- centipedes - carnivores, each segment has 2 pair of legs
-
hexapoda (insects)
- several complex organ systems
- wings (evolved once in insect species) are extension of the cuticle
- incomplete metamorphosis (grasshopper) vs complete metamorphosis (butterfly)
- sexual reproduction, mate once
- carriers of many diseases
- consume enormous quantities of plant matter; play key roles as predators, parasites, and decomposers, an essential source of food for larger animals
-
hypotheses for diversification of insects:
- specialized feeding on gymnosperms and other carboniferous plants
- evolutionary expansion of angiosperms
- flight advantages - escape predators, find food and mates, disperse to new habitats
-
crustaceans
- highly specialized appendages
- may have swimming larval stages
- cuticle for diffusion or lungs
- ex barnacles - sessile, extend appendages outward, cuticle hardened into shell
- decapods - lobsters, crayfish, crabs, shrimp, etc
-
echinoderms (deuterostomia)
- slow moving or sessile, marine
- thin epidermis covers an endoskeleton of calcareous plates; prickly from skeletal bumps
- typically radially symmetrical (not truly, disproved by madreporite of the water vascular system)
- larvae have bilateral symmetry
- water vascular system - branch into tube feet
-
asteroidea (echinodermata)
- sea stars - arms radiating form a central disk
- underfaces bear tube feet
- begin digestive process out of its own body
- regenerative
- tube feet - attach by combination of muscular and chemical action
- sea daisies - armless, absorb nutrients though a membrane that surrounds their body
-
ophuroidea (echinodermata)
- brittle stars - long flexible arms
- move primarily by lashing arms
- use tube feet to grip substrates
- some are suspension feeders, others are predators or scavengers
-
echinoidea (echinodermata)
- sea urchins and sand dollars
- no arms
- 5 rows of tube feet, slow movement
- muscles that pivet their long spines
- jaw-like structures
-
crinoidea (echinodermata)
- use arms in suspension feeding
- sea lilies - live attached to a substrate by a stalk
- feather stars - crawl about by using their long flexible arms
-
holothuroidea (echinodermata)
- sea cucumbers
- lack spines
- endoskeleton much reduced
- bilaterally symmetrical (elongated in their oral-aboral axis)
- five rows of tube feet
-
chordates
- mostly vertebrates
- includes two subphyla of invertebrates: lancelets (cephalochordata) and tunicates (urochordata)
- plus hagfishes (mynixi)
- bilaterally symmetrical coelomates with segmented bodies
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