dino midterm 2
Terms
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- How fossilization works
- bones in a deposition area, animal dies and bones are left in newly lithified rock
- most/least likely to be fossilized
- most likely: animals in deposition environment, larger animals least: smaller, more fragile animals
- kinds of fossils
- bones, sedimentary structures, trace fossils (trackways, etc), soft structures (freezing, drying, etc), gastroliths and coprolites
- what the fossil record tells us
- size, morphology, time period, location, diet, synapomorphies, ecology, behavior
- petrifaction
- aka replacement; organic material in bone dissolves and is replaced by minerals
- permineralization
- water with minerals comes through the sediment and holes in the bone are filled with these minerals
- gastroliths
- fossilized stomach stones
- coprolites
- fossilized feces
- relative dating
- age in relation to something else
- absolute dating
- gives dates in years
- radiometric dating
- dates igneous rocks through radioactive decay, with parent product versus daughter product
- age of the earth
- about 4.5 billion years old
- Phanerozioc sequence and boundary dates
- Paleozoic (570 my-245 my) Mesozoic (245-65 my) Cenozoic (65 my-present)
- sequence of Mesozoic periods
- triassic, Jurassic, Cretaceous
- issues in studying the origin of life
- the conditions are impossible to replicate
- lobe-finned fish
- ancestor of all land vertebrates; had the pectoral fin
- amniote egg
- shelled eggs, like the ocean in a shell; teh shell protects, but is thin enough for oxygen to come in through pores, plus the babies can still get out
- diapsids
- have skull with two openings, the diapsid skull
- synapsids
- mammals and their ancestors; single, lower temporal skull opening
- "pelycosaurs"
- wastebasket term for primitive synapsids; ectotherms
- therapsids
- erect posture; very small, early mammals; fur-like covering: endotherms
- endotherm
- regulate body temperature internally; all mammalssince therapsids
- ectotherm
- animals who regulate their body temperature externally
- mammalia
- mammry glands (identifies earliest mammals), small and nocturnal to start with, three bones in middle ear
- monotremes
- only living mammals that still lay shelled eggs (ekidna and platypus)
- theria
- syn: live birth
- marsupials
- babies are born as embryos
- placentals
- syn: complex placenta
- complex placenta
- cushions fetus in fluid; blood vessel connection to mother; acts as endocrime gland (hormones); suppresses mother's immune response to fetus
- turtles
- reptiles, anapsid skull, carapace
- anapsids
- no openings in the skull
- carapace
- the dorsal bone in the turtle's shell, covered in dermal scutes
- lepidosaurs
- ancestors of snakes; very small; ectotherms; kinetic skull
- diurnal
- active in daytime (to stay warm: ectotherms)
- nocturnal
- active at night
- kinetic skull
- more flexibility in the skull; some bone loss for a more flexible lower jaw
- pterygoid walk
- snakes use inward-pointing teeth in roof of mouth to "walk" food into their mouths
- mosasaurs
- water lizards; effective predators
- lateral undulation
- moving tail laterally to propel self forward under water
- ichthyosaurs
- dolphin-like; carnivores; amniotes; found fossil of ichthyosaur giving live birth
- plesiosaurs
- short tails, propelled self with fins; lots of teeth; some: long neck; others: short nech and long head
- guilds
- group of species with similar foraging requirements
- pursuit predators
- fast swimmers with torpedo bodies; chase down prey; ichthyosaurs and short-necked plesiosaurs
- ambush predators
- lurk and wait for prey; mosasaurs and long-necked plesiosaurs
- Crurotarsi
- semi erect posture; sun: crurotarsal ankle
- thecodont teeth
- deep-rooted, strong teeth
- semi-erect posture
- legs can be pulled significantly under body; crocodiles' "high walk"
- crurotarsal ankle
- s-shaped ball and socket ankle joint that is more stable and makes semi-erect posture possible
- Euparkeria
- small Crurotari with hind legs longer than front legs: facultative biped: could go on two legs sometimes
- crocodiles
- advanced crurotarsi, amphibious, parental care, at first (Triassic) they were more erect and more terrestrial, nostril on tip of nose, niche replacement from phytosaurs
- phytosaurs
- advanced crurotarsi, Triassic, nostrils right in front of eyes, niche replacement because crocodiles took their niche
- aetosaurs
- terrestrial herbivores, known for their body armor, only in Triassic
- Pterosauria
- not dinosaurs, powered fliers with wings made of kerotin, fur-like body covering, hollow bones, syn: pterosaur wing
- How do pterosaur skeletons show flight adapatations?
- wings, hollow bones, short necks, shortened hind legs
- How did pterosaurs move on the ground?
- hopping?
- Why do we think pterosaurs were endothermic?
- they had a fur-like body covering, flying takes more energy than just walking around, signs of parental care
- determinate growth
- growing to a reproductive age, and then not growing any more (endotherms)
- rhamphorhynchoids
- syn: long tail with a vane on the end, used for steering
- pterodactyloids
- syn: tail short or gone, plus crest on back of head; two distinct morphs: one big with big crest, the other smaller with smaller crest and bigger hips (females)
- habitual bipeds
- animals that are built to be bipedal
- mesotarsal ankle
- a reinforced ankle that flexes straight up and down
- Lagosuchus (underlined)
- mid-Triassic, South America, hind legs longer than front legs
- perforate acetabulum
- bipedal femur isn't pushing straight into acetabulum, so it doesn't have to be as strong, so now there's a hole in it
- opposable thumb
- one finger able to work against the rest, showing that hands/arms aren't involved in locomotion, so that they can do other things
- Ornithischia
- "bird-hipped", syn: backward pointing pubis, new lower predentary bone, leaf-shaped teeth, elongated ischium, elongated illium, oscified tendons along vertebral column (incr. stability)
- competitive edge
- all else being equal, if a group of animals develops a key feature, then they will be dominant
- What does it mean adaptively to be a herbivore?
- need a larger gut, so more room for that (back-turned pubis), need grinding mechanism (either teeth or gizzard)
- How to digest plants:
- need to break down teh cellulose: either mechanical (chewing) or chemical (with digestive enzymes (bacteria in digestive tract))
- predentary bone
- bone in front of teeth on lower jaw, chopping mechanism?, probably covered in keratin in life
- How does the ornithischian skeleton show herbivorous features?
- teeth for grinding, extended room for gut
- Thyreophora
- "shield-bearing", syn: elaborate osteoderms, aka bony armor in the skin, especially on the back
- osteoderms
- bones in the skin
- Eurypoda
- "wide foot", syn: short and stocky metacarpals/tarsals, plus shortened post-acetabular process of the illium, they are getting larger and heavier
- Stegosauria
- syn: plates or spikes running along back bone, tall neural arches with highly angled transverse processes, loss of osciied bakc and tail tendons
- glycogen body
- can be broken down into sugars, "sugar store"
- Ankylosauria
- syn: closure of antorbital and suratemporal fenestrae, secondary palate, and shield-like dermal armor on back an sides
- Defensive stragegies of ankylosaurids and nodosaurids
- they were covered in armor, plus ankylosaurids had a bony club on their tails
- Cerapoda
- syn: diastema
- diastema
- gap in the teeth
- Marginocephalia
- syn: relatively short pubis, plus bony shelf on back of skull
- Pachycephalosauria
- syn: dome head: maybe for head butting
- sexual dimorphism
- consitencies and differences in male/female actions in a single species
- sexual selection
- working to impress and get the best mate
- Ceratopsia
- "horn face", syn: frill at back of skull, plus half of their teeth being replaced by a rostral bone
- rostral bone
- a beak-like structure
- Psittacosaurus (underlined)
- most primitive ceratops
- frill and horn functions
- frill protects the neck, while the horn can be used for defense and fighting
- Ornithopoda
- herd plant eaters, facultative bipeds, syn: jaw articulation below the level of the teeth
- Euornithopoda
- syn: pre-pubis
- Hypsilophodontidae
- small to medium in size, cursorial, social herd behavior
- Iguanadontia
- bipedial, maybe secondarily quadripedal, herd animals
- Hadrosauridae
- syn: cheek-tooth battery, thought to be amphibious but they aren't, many had large crests (species recognition and sexual display
- external and internal fertilization
- external: primitive vertebrates such as fish, internal: amniotes
- intromittent organs
- male amniotes' structures to internally fertilize females
- cloaca
- birds, turtles, crocodiles, probably dinosaurs
- penis
- mammals
- hemipenes
- lepidosaurs and lizards
- medullary bone
- provides extra calcium for shells of eggs
- egg laying habits and reproductive strategies
- some have parental care, so babies might stay ing the nest for a while (trampling shell pieces); others: no parental care (shells untrampled); Maiasaura vs. Orodromeus
- Sauropodomorpha
- specialized herbivores, recurved claw, graviportal
- Prosauropoda
- thumb claw is twisted, smaller than Sauropodomorpha, gastroliths?
- Sauropoda
- even longer neck
- neoteny
- adults keeping some juvenile features
- diplodocids
- largest animals ever, nres fully retracted, all teeth in front of antorbital fenestrae
- brachiosaurs
- front legs longer than hind legs
- camarasaurs
- smaller of the group, herd behavior
- Theropoda
- carnivorous skull and teeth, obligate bipeds, thin-walled hollow bones, hands redued to three functional digits
- maxillary fenestra
- hole in the skull between nares and antorbital fenestra
- obligate biped
- can't be quadripedal
- Ceratosauria
- fusion between bones to make pelvis stronger, then possibly kinetic skulls, sexual dimorphism, and head ornamentation
- Tetanurae
- "still tail", walk with legs in straight line, complete loss of digit 4
- pubic boot
- bony plate at the end of pubis
- semilunate carpal
- half-moon shaped wrist bone, allows birds to fold outer section of wings
- furcula
- fusing of the clavicles, wish bone