Lecture 4 Flashcards
What is a paleontologist?
A person who studies ancient life
Is paleontology related to just dinos?
no
Paleontologists study everything that ever lives besides what?
humans
what do you call someone that studies humans?
archeologist/ anthropologist
What is a fossil?
Any evidence of life preserved in the rock record
What are the two types of fossils?
Body fossils and trace fossils
What are body fossils?
these preserve the animals being such as bones, teeth, skin etc
What are trace fossils?
Is the evidence of movement fossilized, isn’t limited to dinos, can be footprints, trails, or burrows
What is an energy budget?
these are decisions you make to conserve and maximize energy
What is taphonomy?
Study of the processes
between death & discovery, involves studying the cause of death, scavenging, disarticulation, transport by rivers, reworking (moved into a rock unit of a different age), burial, and chemical changes during fossilization
What is the process of fossilization?
animal dies then the dead remains can be buried rapidly or delayed.
If buried rapidly the decomposition and scavenging becomes limited
If buried delayed the remains become exposed (bacteria, scavengers, oxygen) can then be transported and buried or it can be reworked where it’s buried and then transported again and degrades again.
After burial it can then go through chemical changes if the environment favours that to lead to preservation- ie has lots of minerals in groundwater, and then maybe fossil discovery will happen
Each time a sample is transported what happens to the anatomical fidelity of the sample?
it decreases
How does the sedimentary cycle help organisms become fossils?
the sediments cover the organism, bury them and go through compaction and cementation to preserve the fossil
What minerals help the cementation process in the sedimentary cycle?
need silica and calcite to ppt from groundwater and glue sediment
Where does rapid burial occur?
sea floor- have lowest sedimentation deposition as far away from source water
river-lakes- have second lowest
flood plains- get a lot of sedimentation- more rapid burial
In order to become fossilized a dinosaur needs to what? why?
die and be buried quickly, so it’s protected from scavengers (break up and eat dino), transportation (break up dino), and decomposition at the surface (have oxygen deteriorate it)
Different preservational styles indicate what?
diff taphonomic histories, the more disarticulated the more transportation they went through
For a single animal what kind of preservational styles are there?
1) Articulated skeletons
2) Partially articulated and associated skeletons
3) Disarticulated skeletons
4) Isolated bones
For multiple animals what preservational styles do we see?
1) Bonebeds
2) Microvertebrates
What are articulated skeletons?
Bones are in the position they were in when they died and the animal was buried shortly after death
Has highest preservational quality
What is the death pose? What is hypothesized as the reason for it?
tail and neck curled up, can be because ligaments are tightened, get muscle contraction, in river channels the fossil gets oriented this way when the fossil sinks to the base of the channel
What are Partially Articulated and
Associated Skeletons?
some bones are in “life position”. Animal was buried shortly after death following minor transportation
What are disarticulated skeletons?
Can be put back together if all the bones are there
No bones are in “life position”.
Animal was buried following minor transportation
What are isolated bones?
Only a single bone is found
Specimen was buried long after death following extensive transportation
What are bonebeds?
Concentrations of macrofossils (large fossils) consisting of more than one individual, usually the bones are disarticulated or associated
What are bone beds often caused by?
mass death
What are micro vertebrate sites?
are concentrations of small, isolated bones, bone fragments, and other fossils
What are microvertebrate sites caused by?
Caused by the movement of water (heavy bones settle out when flow velocity decreases from a topographic high to a topographic low)
What do microvertebrate sites tell us?
Gives us insight of biological diversity
What is a way to fossilize something using temperature? Give an example
freeze them, this dries out the skeleton a bit and preserves it, for example a 39 000 year old woolly mammoth from siberia
25 000 to 55 000 year old cave lion cubs from siberia
What is the jerkify method for fossilization?
is mummification and dessication, happens when sample is dehydrated and has low oxygen ex: tollund man and edmontosaurus
What is the method of fossilization that involves covering it in something sticky?
it’s called encasement, when the fossil is encased in a sticky liquid or soft tissues break down in tar and bones get pickles and turn black
What are the three types of fossilization that leave unaltered remains?
- Frozen/Freeze-dried
- Mummified/ Desiccated
-freeze-dried
-dry places
-in amber - Encased
-in tar
-in amber
What are altered remains fossils?
fossilize by changing the chemical make-up of the
remains. These are called altered remains.
What happens to altered remains?
they are “rockified”, turned to stone
What is the replacement method for fossilization?
When original material is dissolved and another material takes it’s place, for ex: pyrite or silica- can happen at sea floor no oringal material
What is permineralization?
Water flows through pores and deposits minerals- this happens commonly in bones some oringal material
What is petrifaction?
petrifaction =
permineralization +
replacement
Common in wood- material gets replaced and pores get filled, no original material
What is recrystallization?
Change the crystal structure or
make the crystals bigger due to pressure and heat, loses iridescence, original material changed
What is carbonization?
this is when the specimen is buried, water is squeezed out, and there is only a film of carbon left on the rock, it often preserves 2D structure of vegetation, original materila chnaged
What are molds and casts?
molds are when the fossil leaves indent in the sediment, cast fills the mold w other sediment and gives replica of fossil, has no original material
What are the four trace fossils type?
tracks
burrows
borings
coprolite (fossilized poo)
