L7 - Lopho, Echino, Hemi and intro Chordata Flashcards
What are the phylums of the protostomes?
Annelida
Arthropoda
Mollusca
Onychophora
Tardigrada
What are the phylums of the Lophophorates?
Bryozoa
Phoronida
Brachiopoda
What are the phylums of the Deuterostomes?
Echinodermata
Hemichordata
Chordata
What are the Lophophorates?
Possess a food-catching tentacular organ called a lophophore. Horseshoe shaped fold of the body wall that encircles the mouth and carries ciliated tentacles. All lophophorates are/have : sessile, poorly developed head, secrete a protective covering, u-shaped digestive tract
Lophophorates - what is the phylum bryozoa?
5000spp. aquatic, mostly marine, sessile. Minute (individual animal <0.5mm) - No internal transport system, or gas exchange or excretory organs. Colonial (colony can be many cm’s) - polymorphic (a requirement for many colonial animals), most zooids are feeding (autozooids), but some are modified (heterozooids) for defence, some for reproduction, some for attachment. Due to being sessile, they are encased within an exoskeleton (protection and support), filter feeders, hermaphrodites, planktonic larval phase (aids distribution of sessile animals.
Lophophorates - what is each individual bryozoa called?
Zooid ; often box or coffin shaped. Zooid is surrounded by a wall of chitin, some are calcified. Mouth within funnel of tentacles. Anus outside tentacles. Extrusion of lophophore by increased pressure in coelom, withdrawal by retractor muscles.
Lophophorates - what a bryozoa colony?
Comprised of hundreds of clones of the original settled larvae, via asexual budding. Zooids are attached to one another, with pores in the walls for diffusion of substances between adjacent zooids. Colonies form encrusting sheets, or are erect like plants.
Lophophorates - what is the phylum Phoronida?
14 spp ; marine, worm-like, live in chitinois tubes, buried in sand or attached to shells/rocks. Less than 20cm long, lack appendages. Lophophore projected from end of tube for filter feeding.
Lophophorates - what is the phylum Brachiopoda?
325 spp, lampshells. Vaguely resemble bivalve molluscs, but the two valves are dorso-ventral. All marine, from intertidal to deep sea. Attached to rocks or other firm substrate by fleshy stalk (pedicel) coming through a hole in the back of the ventral shell. Some live within a vertical burrow. Lophophore lies within the valves, which gape open for water current to flow in.
Deuterostomes - what is the phylum Echinodermata?
echinos = spiny ; spiny skin. 6000 + spp, starfish, brittle stars, sea urchins, sea cucumbers, sea lilies. Entirely marine ; show pentamerous radial symmetry (5 part) but : larvae are bilateral, adults show secondary radial symmetry i.e. they have evolved radial symmetry from a bilateral ancestor. Body wall contains endoskeleton made of calcareous ossicles. All are benthic, very slow moving or sessile. Water vasculatory system for locomotion, feeding, sensory perception & gas exchange.
Deuterostomes - Echinodermata - what is the class Holothuridea?
Sea cucumbers. Body like a fat worm or cucumber lying on side; a few cm’s up to 30cm. Mouth and anus at opposite ends; tentacles around mouth ; tube feet. Ossicles very small. Most are surface dwelling detritivores. E.g. Holothuria, Cucumaria, Thyone.
Deuterostomes - Echinodermata - what is the class Echinoidea?
Sea urchins & sand dollars. Spherical body (urchins) or dorsoventrally flattened (dollars). Ossicles fused to form rigid test. No arms, ventral mouth. Body divided into : five ambulacral plates bearing tube feet, five interambulacral plates without tube feet. Test is covered with moveable spines mounted on tubercules. Urchins feed on algae and encrusting animals, which are scraped off hard surfaces by a complex mechanism called Aristotle’s lantern. Have pedicellaria for cleaning and defence. E.g. Echinus (sea urchin), Echinocardium (heart urchin), Mellita (sand dollar)
Deuterostomes - Echinodermata - what is the class Crinoidea?
krinon = lily, eidos = form ; sea lily and feather stars. Sea lilies are sessile and stalked and probably the ancestral echinoderm. Have flexible arms with side branches, or pinnules. Feather stars have evolved from sea lilies, but have lost the stalk. Their arms (oral surfaces) still point up, but have a clasp or small ventral claws, called cirri, for attaching to the substrate. Can swim by raising and lowering arms. Often abundant on coral reefs. Both are filter feeders, using tiny tube feet along pinnules e.g. antedon.
Deuterostomes - Echinodermata - what is the class Stellaroidea?
Stella = star, eidos = form. Starfish and brittle stars in which the arms are very obvious and held laterally. Now called sea stars. Subclass - Asteroidea (16,000 spp); sea stars, arms not sharply distinct from central discs; usually have 5 arms. Aboral (upper) surface usually granular to the touch; have pedicellaria of various sorts, as in the urchins. Mouth central on oral (ventral) surface ; slow locomotion by tube feet. Mainly predators of large invertebrates, sponges, polychaetes, molluscs. Often automise (sever) their arms when seriously disturbed or attacked; can regenerate.
Deuterostomes - Echinodermata - what is the class Ophiuroidea?
2100 spp, Brittle stars. Five arms sharply distinct from central disc; some have branched arms. Arms highly mobile and easily broken off. Show autonomy, shedding bits or whole arms. Disc only a few cm’s across, arms much longer. Locomotion by arm movement, not tube feet. Can be very abundant, widely distributed. Deposit and filter feeders, scavengers, predators. Often show diversity of feeding in a single species = very successful
Deuterostomes - what is the phylum Hemichordata?
Phylum of marine deuterostomes animals and are a sister group to the echinoderms.
Deuterostomes - what are the two main classes of the phylum hemichordata?
Enteropneusta (acorn worms), and pterobranchia, and a minor third class, Planctosphaeroidea. Commonly, this phylum is known as the acorn worms as they are the most well known class within them. Mostly burrow dwelling, marine worm-like animals. Some are deposit feeders, others filter feeders.
Deuterostomes - What are the three sub-phyla of the phylum chordata?
Tunicata and Cephalochordata - which makes up the invertebrates. Vertebrata - animals with backbones
What do Chordate have?
Possession of a notochord, visceral clefts in pharynx, CNS hollow, dorsal and tubular. Heart ventral, post-anal, metamerically segmented tail
What is the evolution of the chordata?
Primitive sessile arm-feeder, shift from arm-feeding to gill filter-feeding, acorn worms, ancestral tunicate with free-swimming larva, tunicates, advanced chordate; sessile adult stage lost, amphioxus. Primitive filter-feeding vertebrate.
What do non-chordate have?
CNS ventral, solid and double. Heart dorsal, absent.
What is a notochord?
A key feature of chordates, a tough but flexible rod to which muscles may be attached. Function is replaced by vertebral column
Deuteostomes - Chordata - What is the sub-phylum tunicata? What are the class?
Ascidiacea (ascidians or sea squirts) main class of ca. 2000 species, adults are sessile.
Appendicularia (larvaceans) - adults look like the larval stage (neotenous group).
Thaliacea - salps, free swimming, pelagic adults.
Sorberacea - abyssal ascidian-like forms
Deuteostomes - Chordata - Tunicata - What is the class Ascidiacea?
Ascidians or sea squirts ; main class of ca 2,000 species, adults are sessile. Fertilised egg, tadpole larva, sessile adult. Two forms, solitary and colonial. Examples of solitary forms - Rhopalaea, Didemnum. Examples of colonial forms - Botrylloides leachii
Deuteostomes - Chordata - Tunicata - What is the class Appendicularia?
Adults look like the larval stage (neotenous group). Fertilised egg, tadpole larva, adult retains larval characteristics but sexually mature.
Deuteostomes - Chordata - Tunicata - What is the class Thaliacea?
Salps, free swimming, pelagic adults. * watch the videos
Deuteostomes - Chordata - Tunicata - What is the class Sorberacea?
Abyssal ascidian-like forms
Deuteostomes - Chordata - What is the subphylum Cephalochordata?
Small group of fish-like animals called lancelets. They feed by filter feeding. Estimates of the divergence of cephalocordates from vertebrate lineage using molecular clocks. Aldolase the highest, Twist the lowest
Deuteostomes - Chordata - What is the subphylum Vertebrata?
Cranium (protects the brain), vertebral column (bone and/or cartilage). Highly developed tripartite brain. Forebrain - olfaction, midbrain - vision, hindbrain - hearing. Development of neural crest (involved in the formation of part of the head.
