Molecular Revolution Flashcards
What happens as soon as an organism dies?
Microbes contaminate the DNA.
DNA breaks down quicker in the presence of water/air.
What is the history of ancient DNA?
- Pre 1970: claims of ancient DNA were disproved
- Since then, most of the genome of the woolly mammoth has been sequenced
What is the woolly mammoth closest related to?
Asian elephant
Has any dinosaur DNA been found?
Not much due to lack of exceptionally preserved fossils.
But some Trex protein sequences from bone derived collagen
What are the 2 theories for the origin of anatomically modern humans?
- Multiregional hypothesis: modern humans evolved in many parts of the world from Homo erectus who dispersed from Africa 1-2 MYA
- Out of Africa hypothesis: only African descendants of H. erectus gave rise to modern humans. All other regional descendants went extinct. Modern humans spread from Africa 100,000 years ago. (Most correct model)
How can molecular clocks be investigated?
- Compare homologue genes in different organisms
- Work out how many changes there has been over a time period
Why are molecular clocks useful?
- Reflect evolutionary history
- Provide and calibrate a time dimension
What did birds evolve from?
Small, agile, feathered theropods in the upper Jurassic.
Were there many birds in the Cretaceous?
What happened after the KT bolide?
Birds were not common or diverse, there were lots of pterosaurs.
After the KT bolide, dinosaurs were wiped out, birds survived and diversified.
What were the vast majority of birds after the KT bolide?
Neognathae.
8,500 species, 140 families
What does evo-devo research enable?
Enables us to identify genes and their functions, decipher where they evolved on the phylogeny.
How do you study basal chordates?
- By studying hox genes
- See when it duplicated
- Plot on phylogenies where this happened, compare with fossils
- See how hox genes differ
