Test 1 Flashcards
cladistics
uses relatedness to form phylogenetic trees
taxonomy
system of nomenclature that classifies some groups not based on monophyly or group size
ostracoderms
paraphyletic group - extinct, sister of jawed vertebrates
symplesiomorphy
shared ancestral trait among extant spp (condition of common ancestor, not reversal)
apomorphy
derived form of the ancestral trait - gives us synapomorphy when this develops in one ancestor for a branch of the tree
homoplasy
convergent evolution leads to same trait (not common ancestral, ie. wings)
autapomorphy
derived trait in a single lineage
eusthenopteron
fish with tetrapod characteristics but no limbs
when do vertebrates appear
phanerazoic eon
fossil time division hierarchy
eons > eras > periods
Periods in the paleozoic era
Cambrian, Ordovician, Silurian, Devonian, Carboniferous, Permian
Periods in the mesozoic era
Triassic, Jurassic, Cretaceous
Periods in the Cenozoic era
Tertiary, Quaternary
Cambrian Period
541-485 mya. Explosion of diversifying multicellular life
Ordovician Period
485-444 mya, diversification of marine orgs
Silurian Period
444-419 mya, plants and arthropods move onto land
Devonian period
419-359 mya, age of fishes, tetrapods move to land!!
Carboniferous Period
359-299 mya, amniotes and big swamps (carbon deposits)
Permian Period
299-252 mya.. diversification of ancestral mammals and reptiles,, until the extinction. bad. 96% of spp extinct. due to big big volcanoes and global cooling and sea level change
Triassic Period
252-201 mya. diversification of reptiles to dinos, and the first actual mammals
Jurassic Period
201-145 mya. dinosaurs, 1st pterosaurs, lizards
Cretaceous Period
145-66 mya, most of the big dinos, snakes are invented. then… extinction sad face
K-T boundary
the meteorite… in Yucatan peninsula. Killed 76% of spp, mostly large ones.
Tertiary Period
66-2.6 mya, modern terrestrial verts start up
Quaternary Period
2.6 mya - now. homonids, and megafauna and the ice agesss
Triploblasts/bilaterians
has bilateral symmetry and “tube within a tube” body plan which necessitates 3 germ layers (ectoderm, mesoderm, endoderm) thus triploblast.
ectoderm forms..
skin, nervous system, sense organs
mesoderm forms..
muscle, RBCs, skeleton, circulatory system, urogenital
endoderm forms..
digestive system, endocrine stuff, lung cells
blastopore
the hole that forms when invagination of endoderm starts during gastrulation (forms anus in the deuterostomes)
protostomes vs deuterostomes
- anus/mouth (proto- has mouth from blastopore, deutero has anus) and 2. the nerve cord is dorsal to the gi tract in deutero while it is ventral in protostomes (think shrimp)
characteristics of chordates
dorsal nerve cord, notochord, post-anal tail, pharyngeal slits, and endostyle/thyroid
endostyle
homologous to thyroid, groove at bottom of pharynx with cilia that secretes mucus and pushes food into body
what makes chordate pharyngeal slits unique
mesodermal supports between slits
ambulacraria
clade that is sister to chordates. includes echinoderma and hemichordata (these are PHYLA)
hemichordata
phylum that includes acorn worms (burrowing) and pterobranchs (sessile) with homologous pharyngeal baskets to chordates and a special collar (nerve cord) with a different origin.
echinodermata
phylum that secondarily lost pharyngeal slits and became radial. includes starfish, sea urchins etc
salp
free-floating colony of urochordates
when did vertebrates emerge
it’s ??? but between 900 and 542 mya
pikaia
early chordate from Burgess Shale, 505-510 mya. cephalochordate ancestor with myomeres and notochord but no gills.
Haikouella
2 spp, close to vertebrate. from 530 mya found in china. has all the requirements and myomeres, brain, heart, eyes
Opabinia
the 5 eyed shrimp thing from 500 mya with a claw proboscis on his headdd
bilaterians
protostomes and deuterostomes (all are just clades)
split btwn cyclostomes and gnathostomes
500 mya
vertebrate synapomorphies
hox gene duplication, neural crest cells, (maybe) mineralized tissue, keratin, dorsal fin, tripartite brain, closed circulatory system (single-circuit), gill slits skeletal support, 3 chambered heart (sequential), kidney(s)
neural crest forms..
PNS, sensory organs, brain, adrenal glands, pigment cells, secretory GI cells
neurogenic placodes form….
form from the cells just outside where neural crest migrates off. form lens, iris, retina, color vision, nose, inner ear (vestibular apparatus), lateral line (otic part), electroreceptors
hydroxyapatite
CaPO4, woven into bone cartilage etc to fortify
mineralized tissue types and stats
mineralized cartilage (70%) - flexible but less vascular, bone (70%) - can remodel and heal bc vascular), enamel (96%) = enameloid (only in fish), dentine (96%) - also in fish scales
dermal bone
forms intramembranously (outside in), skulls, shoulders, hips from this
endochondral bone
cartilage forms and starts becoming bone from the middle out
cementum
fastens teeth in sockets for mammals
arcualia
cyclostome retained cartilage that protects notochord (protospine)
hagfish fins?
secondarily lost dorsal fin.. L
epaxial
dorsal muscle block
hypaxial
ventral muscle block
hindbrain functions
respiration, circulation
midbrain functions
hearing, touch, motor response
forebrain functions
vision, olfaction, integration and signal processing
dermatocranium
outer skull layer of dermal bone
chondrocranium
endochondral (or just cartilaginous) brain case
splanchnocranium
makes up gill arches, pharyngeal jaws
liver and pancreas arise..
from the gut
kidneys in most verts
just a tube by the GI tract
path of blood in single-circuit system
heart> ventral aorta> gills> dorsal aorta> system (and back)