chapter 21 animals Flashcards
what four features do all chordates share?
notochord, dorsal nerve cord, pharynegeal slit, postanal tail
notochord
a flexible rod that extends form head to tail along the length of a chordates’ back
dorsal nerve
parallel to the notochord
develops into the spinal cord and enlarges at the head end, forming a brain
pharyngeal slits
form in the pharynx in most embryos
multiple uses
invertebrates use it to feed, straining food particles out of water that passes through the slits
in vertebrates, it can develop into gills, the middle ear, or other structures
postanal tail
a muscular tail that extends past the anus
chordates that are invertebrates
tunicates, lancelets, and hagfish
cranium
a bony or cartilage-rich case that protects the brain
do vertebrates and hagfish have a cranium?
yes
[blank] have a series of small structures making up a backbone to protect the spinal column
vertebrates
chordates that have hinged jaws that frame the mouth entrance
fishes, amphibians, reptiles, and mammals
chordates that have limbs and lungs
most fishes have gills; amphibians, reptiles, and mammals have lungs for gas exchange
chordates that have an amnion
reptiles and mammals
amnion
several membranes that surround, protect, and feed developing embryos
which chordate resemble ancestral chordates
tunicates and lancelets
subphyla that lack a cranium and vertebrae
Tunicates and lancelets
chordate larvae that are free swimming; adults are sessile
tunicate
chordate that filter-feed with their tails buried in the sediment
lancelets
craniates without jaws
hagfish and lampreys
craniates
animals that have a cranium
hagfish
a marine invertebrate with a cranium.
secrete sticky slime, which helps them slide their bodies out of danger
lampreys
have cartilage around their nerve cord, so they are the first animals to evolve vertebrae
first animals to evolve vertebrae
lampreys
chordate that have long, slender bodies
hagfish and lampreys
[blank] have cartilage surrounding the brain but not the nerve cord
hagfish
some [blank] use mouth suckers to attach themselves to the sides of fish and drink the blood
lampreys
how did jaws develop?
in very early fish, the skeletal elements that supported gill silts near the mouth may have developed into jaws
aquatic vertebrates with jaws
fishes
[blank] originated about 500 MYA from an ancestory that had jaws, gills, and paired fins
fishes
the most diverse and abundant vertebrates
fish
the two main clades of fishes
cartilaginous and bony
most ancient fishes have skeletons made of [blank]
cartilage
examples of cartilaginous fish
sharks and stingrays
lateral lines
along the sides of cartilaginous and bony fish
sense organs used to detect vibrations
unique features of bony fish
hinged gill coverings and a swim bladder