34 terms

Echinodermata and invertebrate Chordates

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Echinodermata
Animal phylum most closely related to our own; strictly marine, seem to be radially symmetrical, have no head, heart, brain, jointed appendages, or segmentation; deuterostomes, enterocoelous, indeterminate development and radial cleavage
Tube feet
Writhing, suction cup like feet connected with a series of tubes; used in locomotion, feeding, and has exchange
Water vascular system
Series of tubes connected to tube feet; powers tube feet with fluid pressure changes and transports oxygenated fluid throughout the body
Oral surface
Surface on echinoderm instead of a head and tail containing mouth
Aboral surface
Surface on echinoderm containing the anus
Pedicellariae
Tiny pincers that normally attack small animals that settle on the sea star, but can also be large, wickedly curved, and strong enough to capture small fish
Papulae
Specialized structures included in the extrusions echinoderms depend on for gas exchange
Dioecious
Separate sexes
Asteroidea
Sea stars; carnivorous; some can turn their stomachs inside out and secrete digestive enzymes or slide thin flexible stomach inside shells of prey
Brittle star
Ophiuroidea; tend to be solid in construction, tube feet play little role in locomotion, tend to be filter feeders, predators, scavengers, and deposit feeders
Ophiuroidea
Brittle stars and basket stars; typical inhabitants of soft bottoms in the deep sea, may be the most abundant and successful; use flexible jointed arms for clinging or crawling
Basket stars
Ophiuroidea; some work at night and use their arms like a net to capture prey
Crinoidea
Feather stars and sea lilies; suspension feeders that live on particles that settle on their arms and are trapped in mucus
Echinodea
Sea urchins and sand dollars; use tube feet and movable spines for locomotion, some can burrow into hard rock; employ herbivory, detritivory, predation, and filter feeding; similar to snails
Holothuroidea
Sea cucumbers; have spiny skin reduced to a few scattered ossicles; body is an elongated, inflated, sausage-shaped, sluggish blimp; reduced or absent tube feet; more organized water vascular system; most lie on sea floor, mouth at anterior end surrounded by tentacles
Feather stars
Crinoidea; thought to be similar to the first echinoderms; common and diverse long before dinosaurs originated; highly branched arms bear feather-like structures that aid in gas exchange
Sea lilies
Crinoidea; similar to feather stars but are attached to the sea floor by a stalk
Evisceration
Feature of sea cucumbers; process when under attack or stress, the hind part ruptures and part or all of the digestive system and or other legend are expelled and later regenerated
Respiratory trees
Series of branched tubes in sea cucumbers; water comes in cloaca and is forced through and forced out by contraction
Pearl fish
Tropical fish that lives inside the respiratory trees of sea cucumbers; leaves at night to forage and then forces its way back in through the anus
Urochordata
Subphylum of Chordata; the tunicates or sea squirts; free swimming as larvae but sessile as adults; have tough outer covering; are filter feeders; most are benthic, colonial, some are planktonic and live in gelatinous houses; rely on diffusion for gas exchange; have short tubular hearts that can reverse direction; most are hermaphroditic and have external fertilization, also asexually reproduce by budding
Didemnum
Fast spreading sea squirt nicknamed the tunicate from hell; small sea squirt, cause low pH
Stigmata
Slits of the pharynx, where water passes through after the pharyngeal basket and before the atrium
Atrium
Space between the pharynx and body wall
Benthic
Growing on the bottom
Tunic
Tough outer covering of tunicates that contains a cellulose tunicin
Tunicin
Cellulose like carbohydrate that is found nowhere else in the animal world except for in Urochordata
Cephalochordata
Subphylum of Chordata; the lancelets; amphioxus; bury themselves in sand with head exposed and pump water into pharynx, seem to be idealized Chordates, are considered to be the closest relatives to vertebrates; blood has no pigments of cells; hermaphroditic and use external fertilization
Myomeres
Series of muscle segments along the side of the body of lancelets
Vertebrata
Subphylum of Chordata; the vertebrates
Chordates
Bilateral, eucoelomate deuterostomes having well defined segmentation and cephalization, have a notochord, dorsal hollow nerve chord dorsal to notochord, pharynx with gill slits, postanal tail, and an endostyle at some stage in their lives
Notochord
Stiff rod extending along the dorsal side of the animal, common feature of Chordates
Endostyle
Mucus producing groove on the bottom of the pharynx
Paedogenesis
The attainment of sexual maturity in the swimming larva, selection for this is evident in early Chordates for mobile filter feeding rather than sessile feeding