INTRO TO PALAEOBIOLOGY Flashcards
Process of finding a fossil
- Collect fossil in the field (sedementary rocks)
- Prepare fossil in the lab
- Examine fossil and describe in monograph
- Analyse fossil
- Interpret fossil
Collect fossils in the field: How do new fields become available?
New field sites are continuously appearing:
- e.g. coastal erosion
- New regions become open to study e.g. china
How to prepare fossils in the lab?
- Acid etching
- Used to dissolve limestone
How to analyse a fossil
Microscopy:
- Synchrontron & CT scanning
- Finite strain analysis / Geochemical analysis
Interpreting a fossil
Based on modern biological thinking
Pre - 1750’s
The historical development of the science of palaeontology
Galileo was one of the first to say that fossils are the remains of organisms that once lived.
1859
The historical development of the science of palaeontology
Darwin/Wallace propose evolutionary theory (speciation)
Darwin thought the fossil record didn’t support evolution.
1750’s - present
The historical development of the science of palaeontology
Realisation that earth is very old
Pre-1859
The historical development of the science of palaeontology
Different organisms lived in the past (?extinction)
1900’s
The historical development of the science of palaeontology
Medel’s work was rediscovered
Palaeontology was pushed aside when the study of genetics took over
1930’s
The historical development of the science of palaeontology
Neo-Darwinain Evolution (the modern synthesis)
1960’s
The historical development of the science of palaeontology
Plate tectonics
- people realised that continents mvoe around the planet.
- fossils found in Africa are also found in South America because they were once joined.
1972 - the punctuated equlilibrium model
- Stephen jay gould and Niles Eldregdge.
- Went against Darwin’s idea that evolution was a slow continuous process. Turning point for palaeontology.
- Periods of stasis
1970’s-1980’s: The claudistics revolution
A way of studying phylogenies
(classification)
1980’s: Reality of mass extiction
- Discovery of radioactive material - asteroid that caused mass extiction.
- Realisation that there has been 5 mass extictions in earths history
1990’s +: The reality of past, present and future global change
Previously thought that earths climate was stable - realisation that there is constant large changes.
2000+: Molecular biology
- Evo-Devo and the pattern of life
- Molecular biology development has been huge.
What is Palaeobiology?
Recoupling of palaeontology and biology
What are fossils?
- The remains of any past living organim
- Trace fossils e.g. footprints etc
- Chemical fossils
What dominates the dinosaur fossil record?
- Disarticulated, solitary, dispersed bones and teeth.
- Occasionally partial or complete articulated skeletons are found allowing us to know where body parts go and what they are
How to reconstruct a dinosaur fossil from partial remains?
- Skeletons can be reconstructed from several different individuals
- Using evidence from articulated skeletons and our anatomical knowledge
- Then reconstruct “flesh up” the animal based on anatomical knowledge
- Use computer and engineering techniques to work out capability of animal.
- Can mechanically work out the force of the animal - bite, movement etc
What is the nearest living relative approach
?
- Dinosaurs offer a conundrum as they are completely extinct - crocodile are closest living relative (but occupy a different niche)
- E.g. Brachiopod still exsist today but no living dinosaur.
- Birds are sister group but still far away
What do trace fossils show?
Footprints - can allow knowledge of the size and pace etc of the animal
What can a fossil stomach content show us?
- What their diet was.
- Hadrosaurs (duck-billed) dinosaur stomach content fossil with conifir leaves - showed they stripped conifirs for food.
What are Coprolites and what do they show?
- Fossilised poo
- Full of bacteria
- Quite common
- If buried, phosphorus allows the preservation
- Hard to know which dinosaur produced the coprolites.
Soft tissue fossils
- Skin (occasional acceptional preservation)
- Fast preservation in an anaerobic environment
- Not much for dinosaurs
What can Fossilised eggs show us ?
- Species that buried their eggs in nests - lots of preserved eggs.
- Gives some evidence of behaviour - did they give parental care etc
- Some eggs contain preserved embryos.
Feathers
- Modified scales.
- Was discovered in Chinese specimens.
- Feathers do not preserve well.
Fossil Proteins and DNA?
No dinosaur DNA (yet)
What are Gastroliths?
- Gastroliths - some birds/crocs swallow stones to help break up food.
- Dinosaurs also did this - worn like pebbles.
