EVSC 4320 Midterm 2

Sipuncula
“Peanut worms”
Found buried in rock/sediments
Soft body, sometimes have a shell
Introvert connects the tenticles to the trunk, and is retractable
U-shaped disgestive system, anus near mouth, close to edge of benthos
Pogonophora
Small worm
Tentacles at one end, anchor to tube at other
No digestive system
Found in deep vent communities, can be large and red (hemoglobin)
Absorbs nutrients, or symbiosis with bacteria
Echiura
Beige colored, somewhat rare, several inches long
Proboscis is unretractable, like a rolled tongue
Lays proboscis out, and scilia brings in organic material that comes into contact
Tardigrada
Smallest of metazoa, looks like tiny scaled bears
Herbivorous, right stylets puncture cell walls, mouthp placed near, pharynx sucks out cytoplasm.
Can form cysts
Lophophorates
Phylums that share a lophophore, food gathering structure.
Includes Phoronida, Byrozoa, Brachiopoda, Entoprocta
Phoronida
Lophophore looks like a coiled horseshoe with tentacles
Mouth in middle, U digestion
small, lives in sediments
Bryozoa
Very common in coastal environments
Live in colonies, can attach to piers, etc
Looks almost like plants
Tentacles pull down food, passes food down and shares with others in colony
Some individuals are assigned to reproduction, feeding, etc
Later step of “fowling communities”, after bacteria and barnacle buildup
Brachiopoda
Two values, different from molluscs, b/c valves are different, dorsalHave to open to feed, uses lophophore to feed, adductor muscles to open
Lophophore contains most of valve space
Entoprocta
Benthic, have an attachment disc
U shaped digestion
Chaetognatha
“Arrow worms” plankton
Benthic members are more robust, move in interstitial spaces
Can be pelagic, transparent
Structured as a long tube, two sets of lateral fins
Aggregation of nervous ganglier material near ventral surface
Head region contains grasping spines teeth, sensory pits
Little hairs all over body, every species has different placement
Used to sense pressure waves, different species sense different frequencies, go after different prey
Echinodermata, Stelleroida
Phylum, class
Derived radial symmtetry
Exclusively marine
Internal skeleton composed of calcium carbonate plates
Water vascular system, like internal hydraulics
None are parasitic, found in all marine environments
Enchinodermata, Asteroida
Subclass, sea stars
Central disc, 5 soft arms (connected), oral surface faces down
Osicles (internal skeleton) embedded in outer tissue
Tube feet connected to canal system, suction powered by “hydraulics”, attaches to shells, rocks, etc
Two stomachs, one can be exuded out of mouth, begin digesting things like bivalves
Regenerative, can survive as long as severed arm contains part of central disc
Echinodermata, Ophiuruidea
(sub class) “Brittle stars”
Lots of space between arms on central disc
Stomach does not exit, uses teeth to devour food brought in with arms
Ossicles are now in the middle of arms, (wooden snake ex)
Uses arms to wave around, crawl
Has tube feet, more round and not used for feeding
Echinodermata, Echinoidea
(class), urchins, etc
Ossicles are like skull plates, fused together into a sphere
Spines and podia protrude
Oral and aboral surfaces
Diadema, spp
Black spiny sea urchin (Echinoidea class)
Mucusy epidermis covers layer over all of spines, can be left in your skin
Jaws on oral surface, 5 arrow shaped teeth that extend upwards – “Aristotle’s Lantern”
Sand Dollars
Part of Echinodermata, Echinoidea
Compressed urchins
Podia etc, uses them to bury self in sediment through holes in skeleton
Echinodermata, Holothuroidea
Sea cucumbers
Live on benthos, or in sediments
Surface on bottom has highest concentration of tubefeet/podia, called sole
Crown of tentacles at one end
Ossicles are nearly absent,
Wave tentacles in sediment or water column, food sticks to it, wipes it off and consumes in mucus gland
Echindoermata, Crinoidea
(class) most primitive, used to dominate
Well defined ossicles,
Feathery area attached to main body
Suspension feeders
Chardata, Urchardata, Ascidiacea
(class) sea squirts
Can be relatively transparent
In-current pore, ex-current pore, sued for filter feeding
“Turicates”
Basket inside filters out water, endostyle secretes mucus, which spreads out around basket, transports everything into digestive system
Larval form , almost like a tadpole, pelagic
Find a place on benthos to attach, metamorphose into a benthic adult
Chordata, Urchardata, Thaliacea
(class) salps
Entirely pelagic, found in open ocean
Barrel-like form, water flows through cylinder
Contains endostyle that creates mucus web, funnels particles into mouth, constantly consuming
Attach together to form salp chains
So good at capturing small particles, most live in clearer non coastal water
Alternation of generation, stick together with asexually reproduced organisms to form chains
Other organisms live on salp chains (fish, etc)
Chordata, Urchardata, Larvacea
(class)
Secretes gelatinous house
Pelagic, open ocean, filtering
Two channels for water to move through
Moves tail in house to move current
Filters out large particles, smaller particles are led to smaller filer so it can eat
When large filter (grid) is clogged, animal flicks its tail and loses its house, secretes new one