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)
myxini
CLASS of hagfish
hyperoartia
class of lampreys
petromyzontiformes
order of lampreys
agnatha
infraphylum of the cyclostomes
plesiomorphies of cyclostomes
no true vertebrae, no jaws, no paired limbs, undivided nostril
synapomorphies of cyclostomes
velum (muscular appendage for pumping water over gills), muscular tongue with keratinous tongue teeths
hagfish life story
89 spp, around half a meter, live in deep sea and scavenge or eat small inverts/fish. use tongue teeth to tear off whale bits.. can tie themselves into a knot to help pry smth or to escape a grip/predator. direct developers. make slime, eggs develop a long time. 50:1 F:M, may be hermaphroditic
lampreys life story
48 spp small to 1m, live in freshwater or shallowish in north/temperate areas. live 3-7 years as filter feeding larva and then become big parasites (leave the stream) before returning 1-2 years later to spawn. secrete anticoagulant, breathe thru tidal ventilation when attached
anadromous
lifestyle of salmon and lampreys where you’re born in the stream, disperse, and come back to breed and die.
ammocoetes
lamprey larva
conodonts
paleozoic era almmmmost gnathostomes with cone shaped pharyngeal teeth. found as microfossils everywhere but only like 10 are complete. have mineralized teeth, myomeres, notochord, tailfin, eyes (phylogeny is uncertain)
osteognathostomata
includes everyone with dermal bone (ostracaderms)
synapomorphies during ostracoderms
from mid-ordovician to devonian, all have movable mouth plates and external dermal bone. aranaspids and heterostracans are earliest. anaspids, thelodonts, and galeaspids had paired nostrils. by osteostracans they got paired pectoral fins and a 2nd dorsal fin
yaw
rotation on the x-axis from tail thrust
pitch
rotation on y-axis (not roll)
midline fins purpose
prevent roll and yaw
why did jaws evolve
more efficient respiration
branchial arches purpose
1 and 2 form jaws (velum and velum support in agnatha), 3-7 support gills
eugnathostomata + synapomorphies
infraphylum includes bony fish and chondrichthyes. synapomorphies: continuous tooth replacement, centra, jaws, ribs, 4 sets of hox genes (2nd duplication), horizontal septum.
placoderms
paraphyletic extinct group. ~200 genera in silurian-devonian. deep water bottom-dwellers, gnathal plates of teeth. had claspers and live birth
larvaceans
pedomorphic tunicates
cephalochordata, urochordata, and vertebrata are..
subphyla of phylum vertebrata
chrondrichthyes is a..
class
osteichthyes is a…
superclass
mammalia, amphibia, reptilia
classes
transverse plane
cut up like a sushi
saggital plane
vertical cut thru middle of face
frontal plane
horizontal cut thru body, exposes tubes
medial
towards middle of body
lateral
towards distal region of body
homology
when structures are actually from the same source
indeterminate cleavage
at the 8-cell embryonic stage, you can take a single cell and it will generate another embryo without harming the og one (for deuterostomes). enables identical twins
determinate cleavage
not every cell in an early embryo can form a new embryo on its own (true for protostomes)
Ficke eq explanation
rate covaries with pressure differential, constant based on medium, and surface area, and the inverse of path length.
gills developmental origin
endoderm pocketed out and pierces ectoderm.
unidirectional flow
most efficient (tidal is only useful if there is no other option) - water flows in thru mouth/spiracle and out thru gills
ram ventilation
continuously swimming with mouth open to keep water flowing over gills, used by tuna, mackerel, some sharks
buccal pumping
used for unidirectional flow in many fishes. first water is sucked into buccal cavity (opercular suction pump) and then it is pushed over gills (buccal pressure pump)
hyomandibular pouch
area btwn gill arches 1 and 2 that becomes the spiracle
why is spiracle important for unidirectional flow
rays and skates body plan and habits prevent them from taking in water via mouth most of the time, so spiracle is used for breathing.
gill components fit together..
each gill arch has many paired gill filaments which increase their surface area using gill lamellae
countercurrent flow
without it, we only get to 50% saturation, with it we get like 90
obligate air breathers include..
lungfish, betta fish, bichirs, electric eels
falcultative air breathing fish
can supplement oxygen from environment when conditions in water are O2 poor. include walking catfish and most other air breathing fish
accessory breathing organ structure
have projections of gill arch skeleton, usually located in throat chamber
lungs origin
actinopterygian synapomorphy, outpocketing of the gut and they BECOME swim bladders in many spp
physostomy
swim bladder connected to the gut, fish can gulp/release air to regulate buoyancy. connection = pneumatic duct
physoclystic
swim bladder with no connection to outside, fills up with O2 from blood using rete mirable
gas gland
between rete mirable (the blood vessels) and the swim bladder, it releases lactic acid so hemoglobin will put free O2 into blood which can move into the swim bladder
sphincter ovale
muscle that regulates the opening and closing of the chamber of the swim bladder that allows the O2 to dissolve back into the blood, deflating it
strategies for buoyancy in chondrichthyes
fatty liver, urea, trimethylamine oxide in blood
TMAO
trimethylamine oxide, is used to keep shark tissue hypertonic along with urea
the bends explanation
N2 is dissolved into the blood when gas in the lungs is compressed, but it doesn’t stay in the blood at lower pressures which causes air bubbles in the bloodstream if ascent is too fast. marine mammals prevent this by emptying their lungs before a dive (they have a lot of myoglobin to store O2 in muscles).
Ri
refraction index - how fast is light in a spec medium. air is 1, water and eye tissue are around 1.3
eye shapes in fish vs land dwellers
fish must bend the light bc there is not much difference between eye and water Ri, the lens is spherical to bend. in tetrapods, they compensate for the difference by having a bent cornea and a flat lens just for focusing.
chemoreception in fish
the nares and buccal chamber are not connected. they have olfactory lamellae to absorb smells. this is used for hunting, detecting predators, reproduction, migration, alarm detection
mechanoreceptors in water
hair cells with stereocilia move and cause depolarization > triggers neurons, these are mostly on the lateral line. they are located in pores in the canal under the scales. changes in air would not allow this.
cephalic line
part of lateral line system in some fish, head canals in a similar setup.
neuromast organs
on lateral line - detectors attached to nerve, made of cupula (pore with hair cells in jelly), detects movement and is very important for predator detection
semicircular canals
ear canals in fish (1 in hagfish, 2 in lampreys, 3 in gnathostomes), have otolith organs (ear stones) with hair cells at base so when tilt in any direction occurs it is detected (balance, acceleration)
hearing in fish
sound waves travel thru tissue/swim bladder and can be detected by hair cells. some fish have ossicles that connect swim bladder to inner ear. fish can grunt, squeak etc for communication
pit organs (sharks)
aka ampullae of lorenzini. pore with gel that conducts electricity, canal is insulated and base connects to nerves. many are on lateral line. can detect electrical changes associated w earths magnetic field for navigation as well.
electric organ
used to generate electricity, has electrocytes which are flexed like muscles and generate a pulse. signal is sent out and then detected like echolocation, used to detect items around them inc. prey. rate is dependent on spp and sex, animals like knifefish and electric eels do this
iso-osmotic (conformers) include
hagfish, inverts
hypo-osmotic to environment include
teleosts, lampreys
hyperosmotic to environment include
chondrichthyes, freshwater fish
euryhaline
fish that can handle multiple osmolarities in their environment ie. salmon, lampreys, bull sharks, sawfishes, some rays
stenohaline
fish that can only tolerate a specific level of salinity (most fishes)
salt adaptations in non fish
marine mammals - tiny kidney lobules for more filtration, fish and reptiles- glands near eyes to excrete salt
regional heterothermy
large, active fish like tuna and mackerel keep from losing heat by cycling blood in a rete mirable and keep trunk muscles active
acanthodii (monophyletic group)
shark/chimaera group. polyphyodont, tooth whorls with continuous replacement.
acanthodians
the extinct members of acanthodii, paraphyletic “spiny sharks”. lived in devonian-early carboniferous. had spines, paired fins, paired finlets btwn pectoral and pelvic areas, dermal bone and denticles, autodiastylic jaw suspension
chondrichthyes synapomorphies
placoid scales, no dermal bone, cartilage with crystalline structure, ceratotrichia, true claspers, fatty liver, store urea (this could have been earlier)
ceratotrichia are…
made of keratin
the radiations of chondrichthyan diversity
- devonian on (euchrondrocephali/acanthodii) - weird guys (“stem euchondrocephalans”) like edestus (pinking shear teeth), helicoprion, falcatus (dorsal spine for getting freaky), 2. hybodonta in mesozoic, 3. modern diversity of neoselachians starts picking up in the cretaceous
autodiastyly
articulates 2 places with chrondrocranium but does not use hyoid (not very flexible)
euchondrocephali
true cartilage heads, diverged from elasmobranchs 420 mya. few placoid scales
modern holocephali
chimaera/ratfish/rabbitfish. gills are below braincase, mouth is more anterior, no scales. fleshy operculum with 4 gill slits under. claspers and tentaculum (on head), oviparous, store sperm up to 3 years, live deep but come to shallower waters to mate/spawn. whip like tail, some have long or short noses.
euselachii
group with extant and extinct members, mesozoic shark like animals with shark body form, anal fin, and amphistylic jaws (closer but still not as flexible), and forward facing mouths. had narrower bases and longer ceratotrichia than before (old = more radials, less flexibility.)
amphistyly
jaws attached at front and hyoid but less flexible (primitive sharks)
hybodonta
extinct lineage, sister to neoselachi. was heterodont with piercing teeth in the front and crushing in the back.
neoselachi
mesozoic to modern. rays and sharks. diversified in the cretaceous. synapomorphies include hyostyly, sub-terminal mouth, intercalary plates (protect spinal cord), improved lateral line and ampullae, tapetum lucidum
batoidea
modern rays. have dorsal-ventral compression, no anal fin, dorsal eyes and spiracles, ventral mouth and gills, pectoral fins with lots of electroreceptors. euhyostylic, eat hard prey, salt or freshwater. venom (when present) made of enzymes and serotonin, denatured by heat
selachii
modern sharks, includes galeomorphs and squalomorphs (diverged in permian)
tapetum lucidum structure
guanine crystals behind retina
galeomorphs
active, well-known, small spiracles, fusiform, large brain and body
squalimorphs
smaller, deep water, benthic, large spiracles
alternative shark feeding strats
planktivores, parasites (one time a bonnethead was eating grass…. omnivores?)
durophagous
eating hard food ie crustaceans
countershading
very common coloration for ocean camoflage,, dark on top, light on bottom
shark attacking prey actions
first detect with olfaction (long range) then lateral line, then eyes and then electroreception. they raise nose, put jaws out, raise nictitating membrane to protect eyes. and then use electroreception to know when to strike.
shark aggregation
sometimes they migrate to breeding grounds or nurseries (ie great whites, hammerheads), or school for hunting or breeding.
shark fertilization
internal, male will bite female pectoral fin and insert a clasper which channels sperm. uses siphon sac full of water to push it along.
shark offspring
high investment in energy, few offspring, but no parental care
lecithrophy
yolk nourishment
matrotrophy
nourishment from the reproductive tract. could include oviduct walls, unfertilized eggs, yolk sac placenta, nutritive substance produced in uterine projections, or your siblings for sand tiger sharks.
shark eggs
egg case secreted around embryo and yolk, egg hatches in the case, 6 to 10 months of development. moving baby shark circulates fresh water into case.
intromittent organs..
always have a groove, except for placental mammals. smh.
