chapter 28- invertebrates

invertebrates

no backbones, more than 97 percent of species on world, diverse, more than 35 phyla

porifera

basal, sponges, aquatic, sessile adults, no nervous or digestive or respiratory/circulatory/reproductive system, filter feeders, no true tissue/cephalization

choanocyte

water current and filters food from water (collar cells)

amoebocyte

nutrients to cells and differentiates to other cells

mesohyl

structure support

structure of porifera sponges

supported by spicules and protein fibers (spongin) made me ameobocytes in mesohyl

porifera reproduction

asexually (fragmentation or budding), sexually (hermaphroditic diffe M and F), no gonads (gametes in mesohyl), larvae disperse

Eumetazoans (Cnidaria)

Cnidaria (Basal), radial symmetry, diploblastic, aquatic, 2 body forms sessile polp or free swimming medusa, no cephalization

Cnidaria characteristics

sac body with gastrovascular cavity, 1 opening to digestive sac, mesoglea (non cell layers as skeleton, flexible), simple nervous system (non centralized nerve net)

eating habits (Cnidaria- Eumetazoans)

aquatic (sit and wait carnivores), stinging tentacles around moth, catch prey with cnidocytes

namatocyst

organelle in cnidocyte for stinging

Eumetazoans (Ctenophora)

comb jellies, radial and diploblastic, transparent medusa body, moves with cillia, 8 comb plates, carnivores, 2 tentacles

gastrovascular cavity

digestive sac with one opening

lophotrochozoa

some develop lophophore for feeding or pass through trochophore larval stage or neither

plathyhelminthes

lophototrochozoa, marine, flatworms, flukes, tapeworms, gas exhange and waste through diffusion across body surface , acoelomates, cephalization, gastrovascular cavity, no respiratory or circulatory systems,

syndermata

lophototrochozoa, rotifers, free living, aquatic, microscopic, cylindrical body, crown of cillioa, jaws grind up organisms, psuedocoelom, alimentary canal, parthogenisis

annelida

lophototrochozoa, segmented worms, metamerism (external and internal features are repeated), soft body (true coleom acts as hydrostatic skeleton, well developed organ system, closed circulatory system, gas exchange through moist body surface

mollusca

lophototrochozoa, marine, soft bodied with shell, true coeloms, cephalization except bivalves, seperate sexes, trochophore larvae (disperses snail to new locations)

ectoprocta

lophototrochozoa, ex- bryzoan, crown of cilliated tentacles (lophophore) for feeding around mouth

brachiopoda

lophototrochozoa, pedicle, ex- lampshell, crown of cilliated tentacles (lophophore) for feeding around mouth

planaria

free living flatworm (plathyhelminthes)

alimentary canal

digestive tube with 2 openings

parthenogenisis

asexual reproduction, females make more females from unfertilized eggs

major clades of mollusca

polyplacophora (chitons), gastropoda (snails and slugs), bivalvia (clams, oysters), cephlopoda (squids, octopus)

mollusca body plan

muscular foot (locomotion), visceral mass (internal organs), mantle (secretes minerals that makes shell), gas exchange (gills, simple lungs), open circulatory system

earthworms

sedentarians (annelidea), few bristles no parapodia, deposit feeders, aerate soils

leeches

sedentarians (annelids), no bristles no parapodia, fresh water mostly, anti-coagulant (hirudin)

ecdysozoans

ex- crayfish, lobsters, crabs, barnacles, spiders, ticks, and insects, covered by tough coat called cuticle, cuticle is shed or molted (ecdydisis)

2 large phyla in ecdysozoans

nematodes and arthropods

nematoda

roundworms, no segmentation, pseudeocoelom, cuticle, C elegans, plant and animal parasites

tardigrada

water bear, segmented with cutilcle, 2 stubby legs, lives in water, moss, soil, extreme conditions

arthropoda

most diverse, segmented body (2-3 parts), hard exoskeleton and jointed appendages, open circulatory system, and all systems

4 groups in arthropoda

chelicerata, myriapoda, crustacean, hexapoda

hemolymph

fluid pumped in vessels and bathes tissues

chelicerates

most modern (arachnids, spiders, scorpions, ticks, mites), 4 pairs of walking legs, feed appendages (pedipalps and chelicerae), no atennae

chelicerates body plan

cephalothorax and abdomen

myriapods

many identical segments, chewing mandibles, 1 pair of attenae, all terrestrial, milipedes (2 pairs) centipedes (1 pair) poison claw

crustaceans

lobsters, shrimp, crayfish, krill, barnacles, marine, 2 pairs of attenae, chewing mandibles, many legs

hexapods

insects, first animals to fly, wings from cuticle extensions

insects bodyplan

head, thorax, abdomen, 3 pairs of legs, 1 pair of atennae, compound eyes, mandibles, complex organ systems

malphigan tubules

excretion of metabolic waste

tracheal system

gas exchange

dueterostomes- enchinodermata

pentaradial symmetry, larvae bilateral symmetry, oral (bottom) and aboral (top) sides (central mouth), no head/brain

characteristics of echinodermata

marine, free living, endoskeleton, large coelom, water vascular system, tube feet

chordata

(lacelets, tunicates, vertebrates), notochord, dorsal hollow nerve cord, pharyngeal slits, post anal tail, endostyle or thyroid gland