Bio final chapter 22 Flashcards
Clade Bilateria
contains two main groups protosomes and deutrosomes, bilateral symmetry plan and triploblastic
Bilateral symmetry helps with what
directional mobility, cephalisation formation of head,
Bilateria most basal phylum
phylum acoela,
characteristics
-small flattened body, minimal cephalization and simple nerve net (lack brain)
-absence of body cavity or complex organs
-simple digestive system-only mouth no gut, or anus, digestion happens within cells
Lophotrochozoa clade
half of animal phyla
no unifying synapomorphy
presence of lophophore in some taxa
presence of trochopore at larval stage
diverse body plans
Platyhelminthes lophotrochozoa
flatworms, triploblastic lack body cavity
mouth and gut but no anus
absence of circulatory or gas exchange
Platyhelminthes lophptrochozoa rhabditophorans
parasitic
suckers or hooks
tough outer layer
life cycle with two hosts
intermediate host- sexual repro
definitive host-asexual
termatodes (flukes) and tapeworms
Lophotrochozoa- lophophorata
Have lophophore for feeding ciliated tenticles around mouth
includes ectoprocta and brachiopoda
Lophorata- ectoprocta
sessile
hard exoskeleton secreting CaCo3
retractable lophophore
U shaped digestive tract
both sexual and asexual (budding)
Lophorata- brachiopoda
sessile suspension feeders
attached to seafloor by stalk (pedicle)
use retractable lophophore for feeding
digestive tract with or without anus
Lophorata- Trochozoa
phylum annelida and molluscs
share
-patterns of early embryonic development
-microscopic, motile, trochophore larvae-planktonic larvae with cilia for suspension feeding
-sensory plate with simple eyespot above band
Trochozoa molluscs unsegmented body plan
snails, slugs oysters, clams, octopuses and squids
soft bodied but protected by hard calcerous shells unsegmented body plan
-muscular ventral foot for locomotion
-visceral mass dorsal to foot with internal organs
-coelom is reduced and mass is within haemocoel
-thin layers of tissue called mantle
-calcerous shell secreted from mantle
molluscs gas exchange
through gills in mantle cavity
molluscs feeding
rasplike radula (cutting food)
Molluscs circulatory system
open circulatory system
haemolymph is circulated into and out of the heart
Molluscs have
dioecious and hermaphrodite taxa
larval stage molluscs
trochopore
Phylogeny of molluscs
Polyplacophora (chitons)
cephalopoda (squids octopuses)
bivalvia (clams oysters)
gastropoda (snails and slugs)
Polyplacophora and what is it
molluscs
chitons
muscular foot functions like suction cup adhered to rocks
body protected by 8 dorsal plates
Cephalopoda
squids octopuses …
absence of external shell
presence of siphon fused from tubes of mantle
long tenticles around mouth
radula is modified into beak
closed circulatory system
complex brain and sensory organs
absence of trochophore larvae
Bivalvia
some taxa sessile (marine muscles)
some sedentary (scallops)
some bivalves can dig with muscular foot or swim by clapping shells
two halves connecyed by abductor muscle
some eyes or sensory tenticles
absence of cephalisation
absence of radula
suspension feeders in gills in mantle cavity
gastropoda
snails and slugs
aquatic have trochophore larvae
terrestrial have direct development
single coiled tubular shell
strong cephalisation
trochozoa annelida
marine and freshwater species
two clades errantia and sedentaria
segmented bodies seperated internally by septa
coelom as hydroskeleton
complete digestive system
closed circulatory system
Trochozoa annelida errantia
mobile predatory
pair of parapodia per body segment
parapodia have numerous chateau and bristles composed of chitin also associated with gills
cephalisation with head antennae and eyes
sexual reproduction and external fertilization which leads to trochophore larvae
Annelida sedentaria
leeches and earthworms
less mobile
some taxa burrow into substrates other live in protective tubes
tube dwelling often have elaborate gills or tentacles used for suspension feeding
NO parapodia
cephalisation with head eyes antennae
some taxa lack larvae stage
