powerpoint 2 Flashcards
traits of phylum chordata
- notochord
- hollow dorsal nerve chord
- endostyle/thyroid
- pharyngeal slits
- post nasal tail
differences bw echinodermata and chordata
use both creatine and argenine; both are derived
what is blood made of?
- 45% cells
- 55% plasma and plasma/serum proteins
- albumins (help lipids dissolve)
- globulins
- fibrinogen
chordata and echinodermata shared traits
BOTH CALLED DEUTEROSTOMES
- primitive chordates have larval form
- similar to that of an echinoderm
what are mollusks, annelids, and arthropods called
protostomes
traits of deuterostomes
“second dent”
second dent is mouth, first dent is anus
radial and indeterminate cell division
mesoderm pinches off of endoderm
traits of protostomes
“first dent”
first dent is mouth, second dent is anus
spiral and determinate cell division
differentiates on its own
what does indeterminate mean
if the 2 cell stage of an embryo is disrupted then the two cells can develop independently
- our early embryonic cells are omnipotent
formation of dents in embryos
zygote > blastula > blastopore > gastrolation > mesoderm, endoderm, ectoderm
why do we assume this all happened in the ocean?
- echinoderms, protochordates, hagfishes, cambrian and ordovician vertebrate fossils are marine
- they’re isotonic to seawater
- the MORE DERIVED verts are freshwater
what distinguishes kingdom animalia
- multicellular
- heterotrophic
- lack a cell wall
what is a notochord
a longitudinal solid cylinder of cartilage
what are pharnygeal slits
“grand central station” of head; can be gills, either temporary (us) or permanent (fish)
what are the burgess shale fossils
ATDABANIAN FAUNA
we found the first chordate PIKAIA GRACILENS there; fine particle sediments preserve soft bodied chordate
hemichordata?
we struggle with continuums and transitional forms
what are the three SUBPHYLA of chordata
urochordata
cephalochordata
vertebrata
what is an intermediate species bw nonchordates and chordates
acorn worms
urochordata examples and traits
sea squirts, thaliacea, and larvacea
- paedomorphosis
cephalochordata examples and traits
myomeres
- blood, but no blood cells
- oxygen can easily diffuse through tissue simply
- live like clams
what sets vertebrata apart from the other subphyla
kidneys
lateral line system (acousticolateralis system= combined hearing and lat line)
W shaped myomeres
1 or more semicircular canals
cranium
neural crest cells
why is vertebrata misnamed
because having vertebrae is not a synapomorphy
what were the first vertebrates
conodonts
- paleoindicators; based on where they are found they can indicate how old the rest of the area is
what is our classification:
kingdom: animalia
phylum: chordata
subphylum: vertebrata
superclass: gnathostomata
what distinbuishes agnatha, what are the three classes?
“non-gnathostomes” aka jawless fish
- myxinoidea
- pteraspida
- myopterygii
myxinoidea
hagfishes
- can expel slime and fibrous THREAD CELLS
- lateral line on head only
- lay eggs, hatch juveniles
pteraspida T
shielded/wing/fins
- not important lol
how to distinguish idae and formes
idae is family; -formes is a living fish class
two orders of myopterygii
Thelodonti
- had a stomach; developed beginnings of intestines
- jawless fish w stomach
Anaspida - LAMPREYSSSSSSS
- single median nostril
- oblique gills
- circular gills
difference between taxonomy and phylogeny
taxonomy is classification (putting into boxes) phylogeny focuses on evolutionary relationships
*** in combination the science is systematics
petromyzontiformes
lampreys!
- 6th sense (full lat line)
- can do osmoregulation
- electroregulation
- large eyes w extrinsic muscles
okay so explain agnathan phylogeny?
- bone is ANCESTRAL
- bony fish is a reversal (bones help w osmoregulation)
- increasing O2 made bone easier to form
yeah and what about gnathostomatan phylogeny?
- jaws
- teeth
- two pairs of appendages
- SPECIES EXPLOSION POOKIES
- happened 450 mil years ago
- lampreys and sharks
what are synapomorphies for gnathostomata:
- 3 ss canals
- real vertebrae
- intrinsic eye muscles
hypotheses for jaws
1: top cervical vertebra came forward to form upper and lower jaw
2: or it was part of the cranium that came down and BAM
holostylic vs amphistylic
just one thing vs separate jaw and cranium
hypothesis for teeth:
sharks: placoid scales = dermal denticles
- scales are ancestral, teeth are acquired
pitch is _____ while yaw is _______
vertical, horizontal
2 pairs of fins is __________ while many pairs is ________
ancestral, derived
