Dino Bio Final
Terms
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- Archaeopteryx
- first known fossil bird, transitional fossil (sitll has teeth and seperate fingers), endothermic
- How do we know that birds are dinosaurs?
- synapomorphies and skeletal similarities; we can see the evolutions, like with Archaeopteryx
- gliding
- more control than parachuting; generally small animals; some degree of climbing specialization; significantly expanded body surface
- parachuting
- able to have a controlled fall by expanding their body surface; no major specailization; pretty small
- powered flight
- evolved three times with birds, bats, and pterosaurs; grants access to food in teh air as well as hard to reach places; allows an easy escape and migration, plus makes geographical barriers less of an object; takes a lot of physical energy and fuel; things that change in fliers: wing orientation, loss of body weight (hollow bones), and rigid bodies
- Hypotheses about how flight evolved in birds
- arboreal theory: flight began from the trees down: gliding first; no anatomical reason for glider to become powered flier, plus why were they in trees in the first place? cursorial theory: flew from the ground up; what\'s the reason? spreading wings while running would slow you down, though arm-flapping could be helpful (like in going uphill)
- paleobiogeography
- the geography of life (where animals live) through time
- dispersal
- changing an animal\'s range
- corridor dispersal
- when there are no geographical boundaries in dispersal
- filter bridge
- when environmental constraints let some animals through, but not others
- island hopping
- when animals end up on islands, from the mainland
- sweepstakes dispersal
- when dispersal happens by chance; most often over large bodies of water, when the vast majority would die
- characteristics of faunas evolving in isolated places
- convergence (certain ecological niches filled repeatedly in isolated places), adaptive radiation, dwarfing, archaic holdovers, biased faunas
- adaptive radiation
- explosion of speciation when there is enough room to spread out and change
- archaic holdovers
- when isloation allows animals extinct somewhere else to persist because they aren\'t as threatened
- biased faunas
- either taxinomically (which groups are there), ecologically (the niches that they fit into), or both
- Alfred Wegener
- first thought that the continents might have once fit together
- Pangaea
- the single land mass that used to consist of all of today\'s continents
- plate tectonics
- the process of continental drift
- Glossopteris
- a flora found all acress the southern continents, lending to the idea of continental drift
- Mesosaurus
- a freshwater reptile found in South America, Africa, and India, lending to the idea of continental drift
- paleomagnetism
- the concept that the polarity of the earth has reversed many times; shown by magnetically charged particles in rocks that preserve polarity and orientation at the time of formation
- polar wandering curves
- using paleomagnetism to find out where continents used to be located
- core
- the very center of the earth, where radioactive decay creates heat
- mantle
- between the core and the crust; the inner mantle is more solid
- oceanic crust
- teh floor of the ocean
- continental crust
- land
- subduction
- when oceanic crust collides with continental crust, and the oceanic crust is pushed under
- evidences for paleoclimate
- deposition environments, rocks of that age, original continent location, plant fossils, pollen
- equable
- fair weather
- ectothermy
- controlling temperature externally, determining how active they can be
- endothermy
- controlling temperature internally by metabolic processes, premitting sustained activity
- homeothermy
- maintaining more or less the same body temperature in 24 hours
- poikilothermy
- temperature fluctuates more in 24 hour period
- inertial homeotherms
- animals so big that they don\'t heat up or cool down completely
- vascularized/Haversian bone
- when bone rings are made around blood vessels
- lamellar bone
- more layers of bone, less blood vessels
- lines of arrested growth
- shows that animal stops growing, then starts again (like tree rings, but less regular)
- respiratory turbinates
- folded bones in teh sinuses that prevent water loss
- arguments for or against dinosaur endothermy
- - must be endothermic to outcompete mammals - body posture built for high activity level - speed and activity level - if dinosaurs started small they\'d have to be endothermic, and big dinosaurs came from small ones - high volume food processing - all living endotherms have Haversian bones - fastest growthrates in endotherms (Maiasaura and T. Rex) - oxygen isotope in bone a good temperature indicator (not much variation in body temp: endotherm) - brain to body size ration - four-chambered hearts - noses: respiratory turbinates: birds have them - predator/prey ratios - faunal turnover - phylogeny (birds are endotherms)
- how extinction is part of the evolutionary process
- exctinction is the expected fate of an organism
- mass extinction
- great spike in extinction levels of many widespread and unrelated organisms
- iridium
- a rare earth metla; tons found at KT boundary; iridium found on asteroids
- shocked quartz
- structure changed by impact
- microtektites
- small glass blobs formed by asteriod hitting earth