Lophotrochozoa Flashcards
(16 cards)
Lophotrochozoa members
Lophophore: a crown of ciliated tentacles
ex. Ectoprocts and Brachiopods
Trochophore larva stage: ex. Molluscs and Annelids
Molecular evidence: Rotifers - lophophore-like feeding device
platyhelminthes - some of which have trochophore-like larvae
Platyhelminthes - Flatworms
- organ-level organization
- majority are parasitic
- no specialized circulatory or respiratory structures
- cephalization (concentration of sense organs, nervous control, etc., at the anterior end of the body)
- Bilateral symmetry
- ladder-type nervous system
Platyhelminthes - Turbellarians or Planarians
- Live in marine and freshwater habitats
- head: blunt arrow shape
- auricles = sense organs
- two light-sensitive eye spots
- Excretory organ functions in osmotic regulation and water excretion
- Asexual
- Hermaphroditic
Platyhelminthes - Flukes (trematodes) and Tapeworms (cestodes)
- Termatodes (flukes) largest group of flatowrms
- well developed reproduction system
- usually hemaphroditic (possessing both male and female reproductive organs)
- complex life cycle
Clonorchis Sinensis - Liver Fluke
food born infection caused by fluke worms
cestodes (tapeworms)
- anterior region w/ modifications fro attachment to intestinal wall of hosts (scolex)
- Body: long series of proglottids
- each segment contains a full set of male and female sex organs
- complicated life cycles
Rotifera
- organ and locomotion and aid direction of food to mouth
- Mastax = pharynx (jaw, crushes food)
- Trophi = jaw for grinding (within mastax)
- abundant in freshwater
- Food source = small fish/animals
Major Annelida Groups
Errantia and Sedentaria
Errantia
- mostly marine annelids
- motile: crawl and burrow on sea floor and swim
- each body segment has a pair of paddle like parapodia for moving
- free ranging predators
- well developed eyes and powerful jaws
Sedentaria
- Less mobile
- some species live inside tubes and gills or tentacles for filter feeding
- Chaetae close to body wall to facilitate anchoring in burrows
ex. Earthworms and leaches
earthworms
- do not have well developed head or parapodia
- Chaetea protrude in pairs from surface of body
- food drawn to mouth by muscular pharynx
- closed circulation
- Hermaphrodictic reproduction
- Clitellum - secretes
1) mucus to protect perm
2) the cocoon - Direct development
Leeches
- found in freshwater
- dorsal flattened head
- No chaetea; no head
- No muscular body wall
- two additional suckers
- some temporarily parasitic
Phylum Mollusca Three Body Plan
Viceral Mass: contains internal organs
Mantle: may secrete shell and/or contribute to development of gills or lungs
Bivalves
ex. Clams, Oysters, Mussels, Scallops
- No head, no radula
- circulatory system open
- separate sexes
- ciliated gills hang down within mantel cavity
- capture tiny food products suspended in water
Gastropods
snails, slugs, nudibranchs, limpets
- elongated flattened foot
- well developed head region
- eyes & tentacles project from coiled shell
- gills found in mantle cavity in aquatic gastropods
mantle functions as lungs in terrestrial gastropods
Cephalopods
Nautilus, Cuttlefish, Squid, octopus
- Head footed: force water out mantle cavity
- tentacles and arms capture prey
- beak used to tear prey apart
- well-developed sense organs
- closed circulatory system
- spermatophore
- Chromatophores
