Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
16 Cards in this Set
- Front
- Back
|
What are the classes under cnidaria and their main characteristics? |
Anthozoa: - no medusa stage - thick mesoglea with many cells - gastrovascular cavity divided by mesenteries - have a siphonoglyph Scyphozoa: - Thick mesoglea that may contain cells - medusa is the most obvious part of the life cycle - usually have long trailing tentacles medusae have four mouth lobes - mouth lobes contain nematocysts - 2 neuron networks - ganglia around bell margin rhopalia (special sensory organs) along bell margin Cubozoa: - 4 tentacles or 4 clusters of them - reduced bell opening - well developed nerve net - well developed rhopalium Hydrozoa: - thin mesoglea with no cells - alternate between polyp and medusa - mostly small |
|
|
Name characteristics of cnidarians |
- two epithelial layers: outer epidermis and inner gastrodermis - contain all four tissue types (connective, nervous, epithelial, & muscle) - jelly like mesoglea between epithelial tissues as connective tissue - two life cycle forms: free swimming medusa, benthic polyp - central hollow gastrovascular cavity - cnidocytes (stinging cells) covered with nematocysts (touch-sensitive bags of dischargeable threads that can have barbs, glue, or toxins on them) - have a nerve net, often with nerve ring at bell margin - light sensitive cells on epithelium - statocysts between tentacle bases for equilibrium - respiration and excretion by diffusion |
|
|
what are the common names for the four classes of cnidarians? |
- Actiniaria: Sea Anemones - Scleractinia: Stony Corals - Gorgonacea: Sea fans and Sea Whips - Pennatulacea: Sea Pens - syphozoa: true jelly fish - cubozoa: box jelly |
|
|
What are the parts of an Actinarian life cycle? |
- some can asexually reproduce by "pulling" in half, or by budding - gonads along mesenteries - eject gametes through mouth - have a planula larvae that with grow and then sink and become a benthic polyp |
|
|
What orders are under octacorallia and their characteristics? |
octacorallia: - use chemicals or poison to discourage predators - tentacles have tiny side-branches called pinnules - more tolerant of environ-extremes than scleractinians Gorgonacea: - each polyp's skeleton is made of the protein gorgonin - may have CaCO3 spicules Pennatulacea: - colony of polyps - gastrozooids (digestion) and autozooids (move water) - spicules give support and colour - may bioluminesce |
|
|
what are the three orders under hydrozoa and their characteristics? |
hydroida: - nerve net plus nerve ring at bell margin - seperate sexes - external fertilization with a planula larva example: hydra - no medusa stage - no statocysts - has a nerve net, but no nerve ring - can retract into a blob - has stretch receptors - has somatosensory cells (sense of touch) on basal disc and tentacles - can move towards light - can asexually reproduce when well fed by budding - sexually reproduce by releasing sperm, but retaining eggs Example: colonial hydroids: - have polyp and hydromedusa stage - budding produces new polyps that usually stay attached - each polyp in a colony is called a zooid - share gastrovascular cavities and food - zooids connected by a stalk and a colony is rooted by a stolon which are encased by a perisarc (coating of polysaccharides and proteins) - zooids can specialize into gastrozooids (eating) and gonozooids (produce hydromedusae) siphonophora: - colonies of polyps and medusae - medusae may jet propel colony or act as sails example: portuguese man of war - polyps include gastrozooids, gonozooids and dactylzooids (defensive) Hydrocorals: - calcareous skeleton - some have many dactylozooids and are called fire corals |
|
|
what are the characteristics of ctenophores? |
- 2-layered body wall - thick mesoglea with amoeboid cells - muscles in mesgoclea (suggesting triploblastic - no nematocysts unless they eat cnidarians - two long tentacles with threadlike prehensile (ability to grip) tentilla covered in sticky collocytes - 2 tentacles withdrawn into sheath on aboral side, therefore bilateral symmetry - locomotion by 8 rows of cillia called comb rows that are often bioluminescent - have direct development (no larval stage) |
|
|
why did bilateral symmetry evolve? |
- anterior end cephalized and centralized nervous tissue for adapting to sense the oncoming environment - mobile bilateralia could actively detect, pursue and capture food |
|
|
what are the characteristics of platyhelminthes? |
- bilateral symmetry - dorso-ventrally flattened - triploblastic, but acoelomate (no body cavity) - mesoderm becomes connective tissue called parenchyma (cells and fibrous tissue) - have a dead end gut (gastrovascular cavity) when present - no circulatory system |
|
|
what are the classes under platyhelminthes and their characteristics? |
turbellaria: - mostly benthic, free-living - have a mono-layered, ciliated epidermis, and use cilia to glide; also use muscular creeping and swimming - have rhabdites (membrane-bound mucus secretions of epidermal glands) for locomotion and predator repellent - some marine species have duo glands (one produces glue while the other breaks the glue) - carnivorous and have a protrusible pharynx near the middle of the ventral side - can swallow food whole - gut shape related to size of worm: micro turbellaria have unbranched guts (rhabdocoel) while other can have lateral branches that extend to the margin of the body (polyclad); if no gut, then acoel - well developed head and sense organs, have a true CNS with ganglia in the head - have 2 interconnected ventral nerve cords - have tactile receptors, chemoreceptors and ocelli (detect light, cannot form images) - excretion by protonephridia that have tubules that run the length of the body with periodic exit pores and draw fluid into tubes via ciliated side pockets called flame bulbs - can reproduce asexually or by interal fertilization - have a muller's larva Monogenea: - ectoparasites of fish, amphibians and have a single host Trematoda: - ex. liver flukes - endoparasites with several hosts (usually lives in a definitive host with intermediate hosts; usually highly specific) - cellular epidermis partially or completely shed during embryonic development and is replaced by a syncytial (multinucleated) tegument that is unciliated and has no intercellular space - ex. liver flukes Cestoda: - specialized gut parasites - adults lack many sensory organs - no mouth or gut; absorb food directly via tegument that has many folds and mitochondria - attach to gut via scolex - rest of body is a line of proglottis (bag of gonads that becomes a bag of eggs) that form by strobilization at scolex - have an oncosphere larva |
|
|
what are the characteristics of the phylum nemertea? |
- eversible proboscis, that is sticky, penetratingm or venomous, in rhynchocoel (fluid filled tubular body cavity) - ciliated, glandular epithelium that produce toxins and sticky mucus for gliding - larger worms can move in a peristalsis-like motion of muscular contraction - have a through gut - have a closed circulatory system with vessels - do gas exchange across body wall - asexual reproduction via fragmentation - have direct development from sexual reproduction with the exception of one order that have planktonic larvae |
|
|
What are the characteristics of the phylum rotifera? |
- have a ring of ciliated epithelium at the head called the corona for feeding and locomotion - most tissues are syncytial - use body surface for gas exchange and excretion |
|
|
what are characteristics of the phylum mollusca? |
- soft bodied - dorsal epithelium forms the mantle that can secrete CaCO3 spicules or shell(s) and drapes over the visceral mass (internal organs) - ventral body wall muscles form the muscular foot - mantle cavity contains ctenidia (gills) as well as for the release of wastes and gametes - have a radula (file-like feeding structure) - small coelom that surrounds the heart and gonads to allow for expansion of the body cavity - most have open circulatory systems with several sinuses that join to form the hemocoel - have an osphradium in the mantle cavity (organ the detects chemicals in the water) - have trochophore larvae - the shell has 3 layers: periostracum (proteinaceous), prismatic (calcareous), and nacreous ( scales of CaCO3 in protein |
|
|
what are the characteristics of the class polyplacophora? |
- 8 shells on dorsum - up to 90 pairs of ctenidia in mantle cavity - cilia create anterior water movement through gut - well developed radula and large digestive gland - open circulatory system - countercurrent exchange system at ctenidia - blood has hemocyanin - nervous system has an anterior ring around gut, 2 lateral and 2 medial nerve cords - may have simple eyes (ocelli) on dorsum |
|
|
what are the characteristics of gastropoda |
- distinct head (two eyes and sensory tentacles) - distinct ganglia - osphradium (sense of smell organ) near gill base - most have a single spiral shell with a proteinaceous operculum on foot to act as a trap door - shell can coil to the right (dextral) or to the left (sinistral) - many have torsion where the visceral mass and nervous tissue rotate 90-180 degrees clockwise to allow head to be pulled in first and foot and operculum last |
|
|
what are the 3 subclasses of gastropoda, their common names, and their characteristics? |
prosobranchia (common snails): - drill like radula that can have venom - many have a tube-like extension of the mantle called the siphon for sampling scents - ctenidia at the front opistobranchia (nudibranchs): - mostly lack shells as adults - have detorsion (begin torsion as larva, but then reverse it) - lateral cavity posterior, lateral, or absent - ctenidia replaced by cerata (horn-like projections that nay contain extensions of digestive glands) - many have a pair of sensory tentacles of dorsum (rhinophores) pulmonata (land snails, slugs, and most freshwater snails): - breathe air by using moist, vascularized mantle cavity that has folds as lung - mantle cavity opens to outside via a pore called the pneumostome (freshwater spp. can close underwater) - most spp. lack distinct larval stages - shelled spp. lack operculum and can use a mucus plug instead |
