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
As in most cnidarians, there are two layers: an outer epidermis and an inner gastrodermis. The mesoglea lies b/w the 2 cellular layers. The cnidocytes are located on the tentacles, each contain a nematocyst. This freshwated hydrozoan lacks a medusoid form.
Habitat: Found attached to algae, mussels, or rocks in the low intertidal zone (marine).
Plumes 5-8cm high, usually arranged in clusters. Main stem with many hydrocladia (branches) that are joined with each "joint" having a hydrath. Feeding polyps small, usually protected by exoskeletal cups called hydrothecae.
Habitat: Cosmopolitan species found from low intertidal to subtidal attached to hard substrates attached to hard substrates.
Anatomy: Polymorphic contains both gastro and gonozooids.
Common member of "fouling" community. Found on docks and pilings in calm marinas. These individuals will lend a furry and bushy appearance to submerged objects they have settled on.
"Portuguese Man of War"
Habitat: Pelagic colonies found off gulf coasts and atlantic coasts of North America but not Pacific Coasts. Found on Western side of Pacific Ocean (east coast of Australia).
Habitat: Widely distributed coastal waters in all oceans (marine)
Liberated disc "from strobula" that is young medusa. The symmetry of adult is laid down. 8 pairs of lappets, manubrium, and mouth is visible.
This stage feeds during summer and fall and produces new scyphostomes by budding. This stage arises from planula larva. In winter, it undergoes strobilization to produce pile of disks (soon to become released ephyra).
Habitat: Found attached to submerged object in a bay or harbor with a swift current (marine).
Perisarc covers entire stem, but does not continue into hydrath (gastrozooid). Hydrath has 2 circles of tentatcles (outer ring has aboral tentacles, inner ring has oral tentacles). Many gonophores grow on surface of hydranth body (hydranths are dioecious)
|Cnidaria||Hydrozoa||Order Chondrohora||Velella||Habitat: Floats at surface of offshore water in temperate and tropical oceans throughout world (marine).|
Habitat: Common on sandflats, low intertidal, and adjacent subtidal areas (marine) **Collected daily**
Sea Pansy The heart shaped purple disk, called rachis, has a fleshy peduncle that anchors the animal in the sand. The colony, made up of many polyps, is capable of luminescing when stimulated. Prey on by nudibranchs and sand stars.
Habitat: Planktonic (marine)
Comb Jelly Body with 8 rows of ciliated plates, called comb rows made up with ctenes, which are used for locomotion. Ctenophores are the largest animals to use cilia for locomotion. A statocyst aids in orientation A voracious, gelatinous predator feeds mostly on other ctenophores, other Beroes, and salps by swallowing its prey whole.
Habitat: found on rocks, wharf pilings, and other man-made structures in the low intertidal and subtidal.
Acontia can be forced out through the mouth and weak spots in the body wall to attack other anemones such as Anthopleura elegantissima. Metridium can asexually reproduce through pedal laceration. Pedal laceration refers to when an anemone moves around breaking off pieces of pedal disk that can develop into tiny anemones. In dense clones of metridium, animals on the broader often develop â€œcatch: tentacles which are loaded with nematocysts and can stretch 12cm or more to explore their surroundings. What do you think is the purpose of these tentacles?
Habitat: Attached to rocks in depth of 24-30m (marine) **collected daily**
Purple Gorgonian Sea fan with slender purple/violet branches with white polyps. The branches form an interwoven pattern in one plane.
Habitat: In depths of about 15-60m attached to rocks (marine) **collected daily**
Red Gorgonian Sea fan with red branches and white polyps. Branches are not in a single plane. An ovulid snail lives and feeds on the branches of this gorgonian.
Habitat: Found on rocks and hard substrates subtidally from 12-30m.
Muricea generally orient at right angles to the flow to filter water and capture particles. As colonies grow, they form annual growth rings in their skeletons. The colony is mainly supported by an internal axial skeleton of gorgonin. Soft tissues of the skeleton are impregnated by spicules.
Habitat: Found on rocks and other hard substrates in the intertidal.
Colonial or solitary Wart-like tubercles on the body column are adhesive structures to which pebbles and shell fragments attach helping to reduce desiccation and provide protection from solar radiation. Acrorhagi, located under the feeding tentacles, are loaded with nematocysts. When Anthopleuera senses another anemone, it will extend the acrorhagi to do "battle" with the invading anemone. In colonies of clones, the anemones on the borders have larger acrorhagi and are called warriors.
Habitat: Found on or under rocks from the intertidal to 10m depth.
Only true coral that lives intertidally on the California coast Bears no endosymbiotic algae in its tissues. Can trap food on tentacles or directly on the mesenteries when the mouth opens widely.
Habitat: On shaded rocks and ledges in the low intertidal to 30m depth.
Lack a calcareous skeleton The feeding tentacles have bulbous tips that contain very large nematocysts. When attacked by another anemone, the mesenteries can be extended through the mouth and have extra nematocysts to help repel the attack.
|cnidocyte||contains cnidocil, nematocyst capsule, operculum, nematocyst, and nucleus|
|nematocyst||concentrated on feeding tentacles and gut, secreted by cnidocyte, released by touch and chemical stimuli, discharged w/ explosive force, used for food capture, digestion, and defense, loaded with nasty toxins, secreted into nematocyst capsule, has barbs, spines, and coiled tube|
|cnidocil||sensory hair, triggers build up of osmotic pressure|
|polyp||tubular body shape, generally stationary, thin mesoglea, has a stalk|
|medusa||umbrella body shape, moves, thick mesoglea, has manubrium. Both polyp and medusa have mouth, epidermis, gastrodermis|
|epidermis||layer of living tissue that has contact with external environment|
|gastrodermis||layer of living tissue that lines the gut|
|mesoglea||layer of non living tissue between epidermis and gastrodermis, gives form, may contain living cells|
|coelenteron||a.k.a. gastrovascular cavity, where digestion occurs|
|manubrium||muscular cylinder where the mouth is attached at the end|
|velum||shelf of tissues from the fringe of the bell towards the manubrium (but not attached!), opening of bell is restricted by length of velum, helps with speed (more force going through a smaller opening) Hydrozoan is faster than Scyphozoan b/c|
|gastrozooid||feeding polyp of Hydrozoans, has tentacles (not all) and mouth|
|gonozooid||reproducing polyp of Hydrozoans|
|dactylozooid||defensive polyp of Hydrozoans, not all Hydrozoans have them, tentacles|
|hydranth||in Order Hydroida, oral end of polyp (mouth & tentacle end)|
|hydrotheca||perisarc surrounding the hydranth|
|thecate||has perisarc surrounding polyps|
|athecate||doesn't have perisarc surrounding polyps|
|gonophore||abortive medusae never set free; here fertilization take place (female)|
|planula larva||what zygote develops into in Scyphozoans and Hydrozoans|
|actinula larva||develop directly into medusae; they swim and feed; in Hydrozoans|
|hydrocoral||Order Hydrocorallina; colonial; secrete substantial calcareous skeleton; only in warm waters; dactylozooids esp. abundant and potent; aka fire coral; Hydrozoan|
|pneumatophore||gas-filled (often CO) float in Order Siphonophora (Class Hydrozoa)|
|scyphistoma||comes from non-feeding planula larva; asexual reproducing polyp form of Scyphozoans; undergo strobilization|
|strobiliation||process where scyphistoma undergoes transverse fission to produce medusa|
|ephyra||reproductive unit = immature medusa that broke away from scyphistoma.|
|body column||the cylindrical portion of Anthozoan that can contract and relax against a hydrostatic skeleton; water volume is constant|
|oral disk||at the end of the body column; contains tentacles and mouth|
|acontia||in Metridium, inside cavity, mostly for digestion, can go out through pores to fight, thin filaments|
|zooxanthellae||symbiotic dinoflagellates; golden brown; in Anthopleura; give animal organic compounds 20-95% and gets metabolic wastes and protection from herbivores and residence from animal; photosynthetic; this is what makes corals able to live and thrive clear tropical waters|
|zoochlorellae||symbiotic green algae that does the same thing as zooxanthellae|
|brain corals||corals in which sinuous grooves lined with sclerosepta (thin raised ridges)|
|gorgonin||pigment found in axial rod of gorgonians|
|sclerites||(=ossicles) calcareous spicules|
|rachis||heart part of sea pansy; contains autozooids (w/ tentacles and mouths) and siphonozooid clusters (suck in or spit out water) and covered with spicules|
|peduncle||tongue looking thing attached to sea pansy; used to stabilize sea pansy in sand (think mollusk foot)|
|comb rows||run oral to aboral; comprised of ctenes; 8 in ctenophores (?)|
|ctenes||used for swimming; partially fused, remarkably long cilia. (comb, think teeth on a comb)|
|colloblasts||sticky cells on the retractable tentacles of ctenophores; used for feeding|
|statocyst||sense organ that informs the bearer of orientation of the body to gravity; comprised of a statolith and setae|
|statolith||single sphere of CaCO3; in the statocyst|