more than 700 mya
ediacaran
choanoflagellates
heterotrophs who ingest their food
Ediacaran fossil
edicarian fossil
sponges, cnidarians
the most primative animal
lack tissues and organs
suspension feeders
have choanocytes
flagellated collar cells that generate a water current through the sponge and ingest suspended food
spongocoel (cavity) osculum (opening)
ancient clade of eumetazoans
animals with true tissues (all except sponges and a couple other groups)
one of the oldest groups in the cnidarians
jelly fishes corals and hydras
developed after the sponges before the ediacaran
exhibit radial symmetry and are diploblastic
body plan is a sac with digestive compartment have one hole
animals with true tissues
overfishing the fish that eat jellyfish larvae
immense increase in animal diversity
about 10 million years long at the beginning of the Cambrian
earliest fossil appearance of many major groups of living animals
new predator-prey relationships
a rise in atmospheric oxygen
evolution of the hox gene complex
animals with left and right sides
originated in the ediacaran right before the cambrian explosion
the rise of predators
set of morphological and developmental traits
whether or not there is symmetry along an axis
radial or bilateral symmetry
dorsal and ventral, right and left, and anterior and posterior ends
symmetry is present along a radial plane
like a starfish
collection of specialized cells
tissues that give rise to future muscle and organs
endoderm ectoderm and mesoderm
germ layer between the ecto and endoderm layers
germ layer covering the embryos surface
innermost germ layer lines the digestive tube
digestive tube
animals with two germ layers (endo and ectoderm)
animals that have three germ layers meso ecto and endoderm
a body cavity
cushions internal organs
development of a head
all animals share a common ancestor, sponges are basal animals, eumetazoa is a clade of animals with true tissues, most animal phyla are bilaterians, most animals are invertebrates
a clade of bilaterians
includes mollusks and annelids
chitons gastropods bivalves and cephalopods
group of mollusk
oval shaped marine animals with eight dorsal plates
snails, slugs
make up 3/4 of mollusks
have a single spiraled shell
group of mollusks
clams oysters mussels and scallops
have a shell divided into halves
group of mollusks
squids and octopi
carnivores with beak-like jaws surrounded by tentacles of their modified foot
phylum of lophotrochozoa
bodies composed of fused rings
phylum of lophotrochozoa
soft bodied protected by a shell
have a foot, visceral mass and a mantle
water filled mantle cavity and use a rasp like radula to feed
an annelid
many are parasites
secrete the chemical hirudin to prevent blood from coagulating
clade of bilateria
shed an exoskeleton through ecdysis
two largest phyla are nematodes and arthropods
phylum of ecdysozoa
includes nematodes, guinea worm, and pinworms
phylum of ecdysozoa
2/3 of the known species, date back to the cambrian explosion
are found pretty much everywhere
body plan is segmented, hard exoskeleton and jointed appendages
chelicerates
myriapods
insects
crustaceans
phylum of ecdysozoa
includes echinoderms
animals with a backbone
originated 500 mya in the cambrian
first animals with mineralized mouthparts
jawless vertebrates
2 groups myxini (hagfish) and petromyzontida (lamprays)
myxini
30 species
cartilaginous skull and axial rod of cartilage derived from the notochord but lack jaw and vertebrae
lamprays
38 species
oldest living lineage of vertebrates
cartilaginous segments surrounding the notochord and arches partly over the nerve cord
jaw vertebrates
includes chondrichthyans and gnathostomes
sharks and rays
skeleton of mostly cartilage
streamlined and swift swimmers
carnivores
have a short digestive tract
have acute senses
a ridge that increases the digestive surface area in sharks
clade of gnathostomes
majority of vertebrates
includes bony fish and tetrapods
a type osteichthyans
a lineage of osteichythyes
have muscular pelvic and pectoral fins
3 surviving lineages
lungfishes coelacanths and tetrapods