week 2 Flashcards
define taphonomy
study of all natural processes after an organism dies, incl decay, scavenging, fossilization, etc
what is bloat and float?
when an animal dies, its body fills with gas and it can get easily transported by water
which of the following reasons may describe why is it hard to find complete dino skeletons? (more than one answer is correct)
- carnivores are messy eaters
- water currents can move body parts away from the rest of the body
- sunlight weakens bones, making them prone to erosion
- can be trampled by animals
- mineral contents can be leached away
all of them lol
what is plastic deformation
when pressure causes the shape of a fossil to change, even after the pressure is removed (immense pressure from burying)
what are the best environments for fossilization? what are some examples of these environments?
wet environ
an animal is about to die. later, we find its fossil. what was the environ of the animal like when it died?
- wet or dry?
- high or low elevation
wet and lower elevation
what is the difference between a fluvial and lacustrine deposit?
fluvial is for rivers/streams, lacustrine is for lakes
lacustrine is better at preserving finer details (soft tissue, hair, feathers, etc)
what are the terms for former lake and river/stream deposits?
lacustrine and fluvial, respectively
are they any marine dinos?
no marine dinos, but dino bones can be found in marine environs bc they get washed out to da ocean
desert environments are not good for fossilization. why? if so, how come we find so many fossils in the desert?
fossils aren’t good for fossilization bc aeolian (wind based) deposits are prone to erosion before fossilization occurs
desert environs are often formally wet environs that dried out, meaning that the now sand dunes collapsed on the animal and preserved them under the sand
what are the following rocks composed of?
- sedimentary
- igneous
- metamorphic
what rock are we most likely to find fossils in
sedimentary: sediments (sands n shit)
igneous: volcanic rock
metamorphic: rocks that get hit by heat and pressure and transform!
sedimentary rocks are the best for fossilization bc sediments idk
how do the following rocks form? where are they found
- mudstone/shale
- sandstone
- coal
- limestone
mudstone/shale: mud + silt
found at lake bottoms
sandstone: sand
found at former beaches, river channels, ocean floors
coal: compressed organic material
found in swampy environments
limestone: accumulation of shells + exoskeletons of marine inverts
found in shallow marine environs
what are the two main preservation styles?
premineralization: water soaks into the bone and preserves it
replacement: original bone decays and minerals take up the space, making a cast
what are the best environments to find fossils
areas w recent erosion (dry)
badlands are good since they have little vegetation and are high in erosion
are vegetations good or bad for fossils
bad since they ground the soil, so soil doesn’t blow away
what is overburden
the rocks n shit around a fossil
name the tools used in removing overburden
heavy: shovel, pickaxes, jackhammers, bulldozers
light: hand picks, brushes
how do u transport a fossil? do u just raw dog it or do u protect it?
- wrap in protective material
- cover in strips of burlap and soak in plaster
this creates a hard protective shell that will preserve the fossil
what can a bone tell us?
- disarticulation
- orientation of bone may tell us about river current
- abrasions can tell about travel distance
- presence of tooth marks may indicate predation
how can glaciers help us find fossils?
when glaciers recede they clear away lots of vegetation and sediments
why is dino park good for finding fossils?
was originally under where a glacier receded –> lots of sediment and vegetation cleared away
also is very dry so sediments will blow away, but this runs the risk of the fossil getting exposed too quickly
a animal dies in a desert, a forest, and a mountain. which fossil is most likely to be preserved?
none of them, actually
desert: dry and wind-based depostits –> will likely not cover the dino bones fast enough, so it will erode and weather away
forest: filled w microbes –> will decomp the fossil
mountain: will experience a lot of weatherin –> will decomp the fossil
what can long bone alignments tell us?
when the long bones of a fossil line up, it means the water flow of a channel moved it to be like dat
what evidence of fossils do we have the most of?
teeth - dinos had hella teeth so they dropped old teeth when they ate
enamel also hardens which makes it good for preserving
what are bone beds?
the former mouths of river deposits, where fossils are likely to accumulate
what is a airscribe?
a special baby jackhammer meant specifically for getting rid of tough rock on the fossil
i found 12 teeth, 2 left femurs, and 6 vertebrae. how many individuals are here?
2 individuals, since there are two left femurs. there is only one left femur per body.
bone fragments sure are useless aren’t they!
spiral in bone tells usabout processes that happened while the dinosaur was alive - if the spiral occurred while it was dead, the bone would just break
spirals are shit like tooth chips, bone chips, etc
what can we learn from a tooth with a root vs a tooth without a root?
tooth without a root is just normal shedding
tooth with a root indicates some shit went down, bc usually the root gets resorbed
– tooth got ripped out or something
what are long bone alignments? if bones are not found in long bone alignment, what does this imply?
long bone alignment occurs due to flowing water - random orientation implies still water alignment
