Lab Week 9: Ecdysozoans

characteristics of clade ecdysozoa

ecdysis: molting (Change in size or form)

includes phylum nematoda, tardigrada, onychophora, and arthropoda

characteristics of roundworms

bliateral symmetry, triploblastic pseudocoelomate, protostomes, ubiquitous

characteristics of nematodes

some free-living, but most are parasites

adaptations for parasitic life including thick cuticle, abundance of reproductive structures, reduced digestive system, reduced sensory structures

typically dioecious

characteristics of turbatrix aceti (vinager eel)

free-living, random movement, only possess longitudinal muscles (lack circular muscles)

characteristics of Ascaris (human intestinal roundworm)

parasitic, dioecious, dimorphic

male has a hook on the end and is shorter than the female

trichinella spiralis

a larval worm that develops and lives inside a cyst, cause of trichinosis (contracted from eating undercooked pork)

dirofilaria immitis

dig heartworm

what is included in superphylum panarthropoda?

phylum tardigrada (water bears), phylum onychophora (velvet worms), arthropoda (jointed appendages)

characteristics of phylum tardigrada (water bears)

small (<1mm), bilateral, protostome, true coelom visible near gonads

cuticle - rigid, non-living exoskeleton made of chitin

segmentation and lobopoal (unjointed) legs on each body segment (excluding the head) with claws

open circulatory system - body cavity (hemocoel) filled with fluid to transport blood/oxygen

tun state (desiccated) - survive extreme temperature, pressure, radiation, open vacuum of outer space

dioecious - some undergo parthenogenesis

herbivores & carnivores

characteristics of phylum arthropoda

bilateral, triploblastic eucoelomate, protostomes

largest phylum on earth (adaptations for feeding, moving, and reproduction made them such a diverse and successful group

cuticle made of chitin, segmented & jointed appendages - a pair on each body segment, open circulatory system - heart pumps hemolymph (“blood”) through open spaces (hemocoel)

what is included in phylum arthropoda?

subphylums myriapoda, chelicerata, crustacea, hexapoda

characteristics of subphylum myriapoda

unbranched (uniramous) appendages and single pair of antennae

class diplopoda (millipedes) - 2 pairs of legs per segment

class chilopoda (centipedes) - 1 pair of legs per segment, poisonous claws behind head

characteristics of subphylum chelicerata

cephalothorax and abdomen regions, six jointed appendages for manipulation of food, locomotion, defense, copulation

chelicerae - first pair, pedipalps - second pair

all others used as legs

characteristics of class merostomata (horseshoe crabs) (subphylum chelicerata)

living fossils - around for 350 million years

book gills - highly folded gills

compound and simple eyes

characteristics of class arachnida (spiders, scorpions, ticks, mites) (subphylum chelicerata)

some have modified chelicerae into fangs - inject venom

book lungs - highly folded lungs

spinnerets - secreting silk

characteristics of crustaceans

cephalothorax and abdomen

biramous appendages - two jointed branches from a single base

two pairs of antennae

mandibles - jaws

two pairs of maxillae - hold and manipulate food

characteristics of class malacostraca

order decapoda (10 legs, lobsters and crayfish)

cephalothorax covered in carapace - hard chitin covering

maxillipeds - appendages on 1st segments to chop food and pass to mouth

chelipeds - 4th segment, large pinching claws

large four segments - walking legs

dioecious

swimmerets used for swimming and holding eggs in the females (swim backwards)

characteristics of class insecta (subphylum hexapoda)

most diverse, abundant, successful class of organisms

what are common orders of insects?

odonata - dragonflies and damselflies

orthoptera - grasshoppers

blatteria - cockroaches

lepidoptera - butterflies and moths

diptera - flies

coleoptera - beetles

hymenoptera - bees and wasps

characteristics of insects

uniramous appendages

head, thorax, and abdomen regions

gas exchange via spiracles (pores) that allow air to enter tracheae (air tubes interfacing with tissues)

excretion through Malpighian tubules

tympanum - hearing

many undergo metamorphosis - reduces intraspecific competition

have the ability to fly - aids in dispersal, increases genetic diversity

what is the deuterostome pattern of development?

blastopore becomes the anus, radial cleavage, indeterminate development, coelom forms from out-pocketing of archenteron

characteristics of phylum echinodermata

triploblastic eucoelomate (complete digestive system), all marine, dioecious, larvae bilateral, adults pentaradial, dermal endoskeleton (calcium carbonate)

water vascular system - locomotion and food acquisition, canals connected to tube feet, ampullae (muscular sacs use hydrolic pressure)

pedicellariae - pincher-like spines

lack definite head and decentralized nervous system - ring with radiating nerves, regeneration, catch connective tissue (where the collagen component can transform from one state to another)

six classes of phylum echinodermata

crinoidea, asteroidea, ophiuroidea, echinoidea, holothuroidea, concentricycloidea

characteristics of class asteroidea (sea stars)

body: central disk and 5-20 arms

oral surface: mouth on the underside of the body

aboral surface: madreporite on top of the body (entrance to the water vascular system, madreporite, stone canal, ring canal, radial canal, tube feet)

pushes stomach out of the mouth and into prey, gas exchange via dermal gills, circulation of coelomic fluid, dioecious

what is included in class crinoidea?

sea lilies & feather stars

what is included in class ophiuroidea?

brittle stars and basket stars

what is included in class echinoidea?

sea urchins, sea biscuits & sand dollars

what is included in class holothuroidea?

sea cucumbers

characteristics of class holothuroidea

modified tube feet form tentacles around the mouth

gas exchange via respiratory trees (located inside the anus/cloaca, cloaca pumps water in and out for respiration)

defense mechanisms: shooting sticky tubules from their anus (typically release toxins), eviscerate themselves when stressed or threatened (digestive tract, respiratory tree, gonads)

characteristics of phylum chordata

bilateral, triploblastic eucoelomate, terrestrial and aquatic