By Levi Clancy for Student Reader on
- Binomial Nomenclature
- Caenorhabditis elegans
- Coliform Bacteria
- Darwinian Evolution
- Drosophila melanogaster
- Evolutionary Chronometer
- Evolutionary Constraints
- Evolutionary agents
- Phylum Annelida
- Phylum Cnidaria
- Phylum Platyhelminthes and Nemertea
- Phylum Porifera
- Reconstructing Phylogenies
- Taxonomic Units
Habitat: Benthic in lakes, ponds, streams, and springs all over the world (Freshwater)
Mouth opens on ventral surface and leads to pharyngeal cavity (elongate chamber that houses pharynx). Frequently used in studies of regeneration. Differ from Planaria in possessing eyes with multicellular retinas and pigment cups. Over 100 species have been described, many of which reproduce by asexual fission.
Habitat: Freshwater, occurring only in Northern hemisphere.
Approx. 80 species described (from family planariidae). Characterized by a digestive tract in 3 branches: One anterior to pharynx, 2 parallel posterior to pharynx.
Habitat: Parasites in the bile passages of many kinds of mammals especially ruminants (sheep and cattle), humans occasionally infected.
Flute or Digenean. Adults feed on the lining of biliary ducts. Eggs are passed out of the liver with the bile and into the intestine to be voided with host feces. If eggs are shed into water they develop in larvae and enter the cell intermediate host. Additional development occurs within the snail and multiple parasites leave the snail and encyst on aquatic vegetation. Encysted vegetation is eaten by the final host (a mammal) and the life cycle is complete.
Habitat: Found in the intestine of most carnivores, dogs, cats, wolves, foxes, humans (parasitic)- the tapeworms.
Bidy consists of segments called proglottids. As proglottis enlarge and become older, they contain male and female reproductive organs which become functional (proglottids). Individuals 3-5 meters long have been reported.
Commensal in book gills of horseshoe crabs. Attach to the host using sticky secretions and a specialized posterior sucker. Females deposit their egg on the host's gills.
Habitat: Found on the lower shore coiled in writhing knots beneath boulders and on muddy sand. This species can often be found in rock pools entangled amongst laminaria holdfasts or in rock fissures. In deeper subtidal areas, it occurs on muddy, sandy, stony, or shelly substrata.
Unsegmented elongated ribbon worm. Common on east coast. Posses proboscis which is used in feeding.
|Auricle||Chemical receptors; ears-like flaps; on Dugesia and Planaria; two pairs of ciliated paddle/tentacle-like structures unique to lobate ctenophores and assist in prey capture.|
|Pharynx||Everts out of mouth to suck up food.|
|Vans Deferens||Where sperm comes from.|
|Penis Bulb||Conical mass inside genital atrium.|
|Gonopore||Where male and female reproductive systems come together and open to the outside.|
|Caudal Sucker||Bdelloura uses it to stick to gills of horseshoe crab.|
|Epidermis||Layer of cells on external side of animal.|
|Gastrodermis||Layer of cells that lines the gut.|
|Parenchyma||Mesoderm; loose collection of cells; forms muscles.|
|Miracidium||Free swimming larva of Trematode Himasthla rhigedana; gutless and ciliated; eaten by intermediate host.|
|Cercaria||Free swimming larva; looks like sperm; get out of first intermediated host; encyst onto snail operculum or belly of crab (2nd intermediate hosts).|
|Metacercaria||Encysted waiting stage on 2nd intermediate hosts.|
|Miller's Larva||Rare planktonic larva of Class Turbellaria.|
|Proboscis||Found on Phylum Nemertea; shot out by hydrostatic pressure of rhyncocoel; used prey capture; hollow.|
|Rhynocoel||Where inverted proboscis lies; fluid filled tubular cavity; aka proboscis sheath.|
|Stylets||At ends of proboscis; spears prey; can secrete toxins.|
|Pilidium Larva||Nemertean larva; feeding, swimming, long-lived (vs. Platyhelminthes).|