Week 4 Flashcards
radial symmetry
animals that have an axis that runs from mouth to base, with many planes of symmetry around the central axis
allows them to move up and down in water column and sweep food from many directions at once
cnidarians
bilateral symmetry
bodies have distinct head and tail and single plane of symmetry running between them at midline
horizontal movement and developed specialised sensory organs
organ systems
insects
simplest animals
cnidarians
sponges
ctenophores
placozoans
sponges
multicellular
interior surface lined by cells called choanocytes
intracellular digestion
spicules for skeleton
mesophyl between interior and exterior cell layers: nutrients and amoeba like cells for skeleton formation
cnidarians
life cycle alternates between sea anemone and jellyfish
predators- catch prey with tentacles and digest it in the gastric cavity
reproduce asexually
diploblastic
gastric cavity digests and excretes
ctenophores
resemble cnidarians in body plan radial symmetry predators- ingestion propel by cilia rudimentary gonads
bilateral animals
lophotrochozoans
ecdysozoans
deuterostomes
chordates
lophotrochozoans
spiral cleavage early in development annelids worms and mollusks predators or ingest sediments mollusks gastropods, cephalopods, bivalves
ecdysozoans 8 phyla
nematodes arthropoda chelicerates myriapods crustacenas insects
deuterostomes 3 phyla
hemichordata
echinodermata
chordata
hemichordata
wormlike
move through sea floor and collect food particles
echinoderms
skeletons made of porous calcite
tube feet
chordates
vertebates
pharynx with pharyngeal slits
body musculated arranges in segments called myotomes
cephalochordates and tunicates
notochord: stiff rod of collagen that runs along back
3 subphyla of chordates
cephalochordates
tunicates
vertebrates AKA craniates
fish
earliest branching vertebrates
earliest branching craniates are hagfish and lampreys
lampreys
vertebrae of cartilage
lack jaw
hagfish
lacks vertebrae
lack jaw
soft foods
chondrichthyes
sharks
deposit calcium phosphate only in teeth and denticles in skin
osteichthyes
bony fish cranium jaws bones mineralised by calcium phosphate swim bladder
amniotes
lack heavy jaw
amniotic egg has dessication resistant shell and four membranes for gas exchange and waste
mammals, marsupials, placental mammals
mammals
covered with hair and feed milk from mammary glands
marsupials
young born at early developmental stage
pouch with mammary glands
placental mammals
placenta develops in uterus to provide nutrition
cambrian period
541-485 MYA
body plans most like bilateral
ordovician period
485-443 MYA
evolution of heavily skeletonised animals in ocean
animals began to colonise the land
420 MYA
organisms most closely related to animals
choanoflagellates
bilateria
triploblastic
protosomes and deuterostomes
protosomes
blastopore becomes mouth
deuterostome
blastopore becomes anus
placozoans
no specialised tissue
cells arranged into upper and lower epithelia that enclose interior fluid
cilia for movement
similar genome to cnidarians and bilateral animals
order of divergence
choanoflagellate sponges sponges ctenophores placozoans cnidarians bilaterians
dendrogramma
some characteristics like cnidarians and ctenophores
annelid
cerebral ganglion NS
digestive system and anus
aquatic annelid
gill like organs
water filtering organs called nephridia gonads
coelom
mollusks
mantle for breathing and excretion
larvae called trochophore
gastropods, cephalopods, bivalves
gastropods
type of mollusk
mouth has radula for feeding
coelomates
predators
cephalopods
class of mollusk
tentacles to capture prey and sense environment
propulsion in water
bivalves
group of mollusk
no heads
two hard shells
filter food from water
ecdysozoans
process of ecdysis or melting
secrete a protein rich coating that covers their bodies
our closest invertebrate relatives
tunicates
permian period
252 MYA
Environmental catastrophe eliminates most genera in oceans
