Animal lect exam 2 - protostomes

protostomes

form the mouth first in development

have spiral cleavage and mosaic development

includes clades lophotrochozoa and ecdysozoa

triploblastic bilatera

triploblastic bilateria

bilaterally symmetric

undergo cephalization

triploblastic

3 body plans

includes deuterostome and protostomes

psuedocoelomate body type

mesoderm partially lines the blastocoel

acoelomate

the mesoderm completely fills the blastocoel

coelomate

coelomic cavity forms inside the mesoderm

dueterostomes

blastopore becomes anus

radial cleavage and regulative development

Phylum Xenacoelomorpha

sister group to bilateria

acoelomates

live in marine brackish or freshwater

Phyulm playhelminthes

flat bodies

within lophotrochozoa

mostly aquatic

blind gut

typically have flame cells (protronephridia)

triploblastic

what do platyhelminthes have that cnidarians dont

organ level system of organization

cephalization

digestive and excretory systems

what are the three tissue layers in triploblasts

ectoderm - epidermis, sensory and nervous structures

mesoderm - muscles, gonads, parenchyma

endoderm - gut lining

ectoderm - ciliated epidermis

in free-living species

contains rhabdites (rodlike organelles for defense and locomotion)

anchor cells

ectoderm - syncytial tegument

in parasitic forms

non ciliated

no rhabdites

anchor cells

flame cells

the simplest excretory system

function as kidneys

use cilia to remove waste

sense organs in platyhelminthes

ocelli

auricles

statocysts

rheoreceptors

reproduction in platyhelminthes

both sexual and asexual reproduction

most are monoecious

usually cross-fertilization

direct development in free living species and species with a single host

Class turbellaria

fee-living

have ciliated epidermis

simple life cycle

paraphlyletic group

can regenerate body parts

class trematoda

flukes, all parasitic

most endoparasites of vertebrates

have non ciliated syncytial tegument

have adaptions for parasitism

what are some adaptions for parasitism of class trematoda

penetration glands

suckers (oral and ventral) and hooks

glands to produce cyst material

increased reproductive capacity

subclass digenea

1-3 intermediate hosts (usually snails as first host)

definitive vertebrate host

in class trematoda

life cycle of digenea (clonorchis sinensis)

adults lay eggs in feces of vertebrate host which infect snails

the eggs go from egg to miracidia to sporocysts to rediae all inside the snail via asexual reproduction

cercaria infect freshwater fish and turn into metacercariae

metacercariae infect vertebrate hosts through the ingestion of raw infected fish

the adults end up in the vertebrate hosts and the cycle restarts

blood flukes

in class trematoda

schistosoma species

dioecious

have gynecophoric canal

clonorchis sinensis - human liver fluke

swimmers itch

cercarial dermatitis

causes itching and rash

fish eating bird is the first host, then mollusc then humans

how can one combat schistosomiasis

reducing snail population

purifying water

medication - treatable

class monogenea

ectoparasitic flukes in platyhelminthes clade

use opisthaptor as attachment organ

simple life cycle: egg - ciliated larva - attach to host

class cestoda

tapeworms in playhelminthes

use scolex for attahcment

no digestive system, use microtriches to increase surface area

made up of repeating proglottids

at least 2 hosts - vertebrate definitive host

Taenia

pork and beef tapeworm

in class cestoda

causes cysticercosis

phylum gastrotricha

acoelomate

“belly hair”

move by gliding on ventral cilia

feed on bacteria and plankton

phylum gnathostomulida

acoelomates

marine

very small

interstitial animals - live in between grains of sand

ciliated epidermis

muscular jaw

monoecious

phylum micrognathozoa

acoelomate

one species

freshwater

interstitial

cilia fo rmovement, snesory bristles

egg producing

complicated jaw for scraping

plylum cycliophora

acoelomate

live on mouthparts of lobsters and other crustaceans (use adhesive disc for attachment)

asexual feeding stage

dioecious - sexual reproduction

phylum entoprocta

acoelomate

mostly marine

suspension feeders

ciliated tentacles

some colonial

what does the ecdysozoa clade have that makes them stand out

their cuticle molting (ecdysis)

advantages of psuedocoelomate body form over no body cavity

hydrostatic skeleton

space for development of more complex organ systems

simple means of circulating materials around the body

phylum nematoda

in ecdysozoa clade

roundworms

unsegmented psuodocoelomates

veriform (worm-like) body

complete gut

cuticle that molts

live everywhere

50% parasitic

body form of nematodes

have collagenous cuticle

longitudinal muscles (no circular muscles)

full digestive tract

have 4 juvenile staged separated by molts

how do nematodes move

hydrostatic pressure

cuticle is laterally flexible but can compress or stretch longitudinally

fluid in psuedocoelom is under positive pressure

nematode reproduction

dioecious

copulatory spicules in males

ameboid sperm

C. Elegans

monoecious nematode

model organism

1st microorganism to have full genome sequenced

Ascaris lumbricoides

nematode

present in 15% percent of the population

high egg production

highly resistant eggs and can last a long time

direct sunlight or extreme heat kills worms and eggs

enterobius vermicularis

nematode

pinworms

most common nematode in north america

have haplodiploidy - males haploid, females diploid (haplid males come from parthenogenesis)

Necator and anclyostoma - hookworms

nematode

hookworms

bloodsuckers

eggs deposited in feces and hatch outside of the body

juveniles wait in soil for mammel contact

contracted by walking barefoot in fecal-contaminated area

trichinella

nematode

trichina worm

can infect humans through cysts in undercooked pork

intracellular parasites - inside the cells of host

transforms host muscle cells into nurse cells

wuchereria bancrofti and brugia malayi

nematode - filarial worms

live in lymph passages and block flow of lymph

cause elephantiasis: excessive growth of connective tissue, swelling

carried by mosquitoes

dirofilaria immitis

nematode - filarial worms

canine heart worm

carried by mosquitoes

found in many mammals

loa loa

african eye worm

nematode - filarial worms

spread by flies

found in subcutaenous tissues

in equatorial africa

onchocerca volvulus

nematode - filarial worms

causes onchocerciasis or river blindness

transmitted by black flies

microfilariae enter the eye and die which eventually results in blindness

Dracunculus medinensis - guinea worm

nematode - not a filarial worm

guinea worm

vector is a copepod - unusual

juveniles scape host via open blister

can nematodes act as bioindicators to tell about the health of ecosystems

yes

phylum rotifera

psuedocoelomate, lophotrochozoa

“wheel bearing”

suspension feeders - use cilia on corona to move water

mostly freshwater

dioecious

Phylum acanthocephala

psuedocoelomates, lophotrochozoa

“thorn head”

all endoparasitic - adults live in intestines of vertebrates

cylindrical proboscis with rows of spines

Phylum Nematomorpha

psuedocoelomates, ecdysozoa

horsehair worms

adults are free living and juveniles are parasitic in arthropods

alter food web through manipulation of cricket hosts

Phylum Kinorhyncha

psuedocoelomates, ecdysozoa

mud dragons

marine

freeliving

scalids - recurved spines

benthic - live on the bottom

Phylum Priapulida

psuedocoelomates, ecdysozoa

penis worms

all marine

chitinous cuticle

retractable and invertible introvert

caudal appendage

benthic

phylum loricifera

psuedocoelomate, ecdysozoa

“corset bearing”

all marine

interstitial - marine gravel

mouth surrounded by curved spines - scalid

whats an advantage that coelomates have

allows for the more stable arrangement or organs, gut tube can be more specialized

Phylum Chaetognatha

coelomate, lophotrochozoa

“bristle jaw and arrow worms”

small predatory marine worms

planktonic predators

monoecious

lophotrochozoa

some have lophophore - crown of ciliated tentacles surrounding the mouth for suspension feeding

some have tropchophore larvae

lack distinct head

who has a lophophore

ectoprocta

brachiopoda

phoronida

Phylum Ectoprocta

coelomates, lophotrochozoa

bryozoans

freshwater and marine

sessile, most form colonies

live in scaly cups

lophophore used for feeding

Phylum Brachiopoda

coelomates, lophotrochozoa

lamp shells

marine

attached bottom dwelling

looks like bivalves but have dorsal and ventral valves instead of left and right

have fleshy stalk attaches to substrate - pedicel

phylum phoronida

coelomates, lophotrochozoa

bottom dwellers, shalloe coastal waters

leathery chitinous tube

who has a trochophore larvae

brachiopoda

phoronida

nemertea

mollusca

annelida

sipuncula