Fossils and Molecular Revolution Flashcards
Give the history of the molecular revolution
1900s - Mendels work is rediscovered and this paired with Darwin to create Neo-Darwinian evolution
1920-1930s - Neo-Darwinian evolution hardened into modern synthesis as gene frequency starts to be explored
1945 - George Gaylord Simpson attemps to bring palaeontology back into the field
1953 - Crick and Watson ‘discover’ DNA (not in the powerpoint but credit Rosalind Franklin)
1960s - Genetic code established
1970s - Technological innovation enables manual DNA sequencing
1980S - Technological innovation enables indetification of genes and gene function
1990s - Technological innovation enables automated DNA sequencing (bacteria in 1995, yeast in 1996, nematode in 1998 and human in 2004)
2000s + - Whole genome sequencing and Evo-Devo studies intensify as technological development becomes more advanced in terms of sequencing ability, data storage, retrieval and analysis
When do molecular clocks get problematic?
When looking at macroevolution events - like origin of animals
What are some major advances of DNA retrieval in the last decades?
Most of the genome of the woolly mammoth has been sequenced - even know gene for coat-colour polymorphisms (as of 2021, got DNA from a mammoth from 1 MYA)
Entire Neanderthal genome has been sequenced
Not got dinosaur DNA BUT have got T.rex protein sequences from bone
Discovered Denisovans from sequencing
Why are fossils incorperated into molecualr analysis?
Reflet evolutionary history - long extinct organisms and traits
Provide and callibrate a time dimension
What were birds like in the Cretaceous?
Many lost the ability to fly - probably because pterosaurs ruled the sky instead
Not very common or diverse UNTIL K/T
Start to diversify and the neognatha radiate (pterosaurs died in K/T)
Did the neognathae evolved before or after K/T?
Hard to determine this due to not many bird fossils - they do not fossilise well due to hollow bones
Fossils that are found and phylogenetic analysis suggest they evolved after K/T
Molecular clocks suggest neognatha evolved earlier than the fossil and phlogenetics suggest - remeber these can be problematic
What can Evo-Devo research allow us to establish?
Genes and their functions
Establish their distribution among living organisms
Decipher where certain genes evolved on a phylogeny
Decipher what functions genes perform (or co-opted to perform)
