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Biology: the science of life. Freaky sea-vent worms. What is life?. Growth and replication. prions? computer algorithms. nucleation = replication?. aluminum potassium sulfate crystallization. What’s missing?. Evolution. Three keys: reproduction, variation, selection. Improved
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Biology: the science of life Freaky sea-vent worms What is life?
Growth and replication prions? computer algorithms nucleation = replication? aluminum potassium sulfatecrystallization What’s missing?
Evolution Three keys: reproduction, variation, selection Improved replicator Neutral variant replicator Improved replicator Life:Reproduction + evolution
Implementing life (physics + chemistry) • Encapsulation and individuality • Reproduction • Energy and material processing(metabolism) • Information storage • Environmental response
Life elsewhere? • Liquid solvent (water) • Mars, Europa, Titan (methane and ethane)
You are here Common descent Genetic and morphological evidence are consistent withall life on Earth sharing common ancestry
History of life on Earth Humans arose very recently (roughly 200,000 years ago). Do this as in-class exercise Microscopic life dominates the history of Earth.
Tobacco mosaic virus Have them adding scales 3x10-7 m in length, 1.8x10-8 m in width ~7x10-20 kg in mass ~6.4x103 bases in genome (single-strand RNA)
Escherichia coli prokaryotic: no cell nucleus ~3x10-6 m in length ~7x10-16 kg in mass ~5x106 base pairs in genome
Saccharomyces cerevisiae eukaryotic: cell nucleus ~5x10-6 m in diameter ~6x10-14 kg in mass ~5x106 base pairs in genome
Arabidopsis thaliana multi-cellular plant ~0.2m in height ~1.2x108 base pairs in genome
Drosophila melanogaster multi-cellular insect ~3x10-7 kg in mass (dry) ~1.2x108 base pairs in genome
Mus musculus multi-cellular ~3.5x10-2 kg in mass ~3.4x109 base pairs in genome
HeLa cell human immortal cell line ~25x10-6 m in diameter ~3.1x109 base pairs in genome
Exercise: How many cells in your body? Exercise: How many bacterial cells in your gut?
Homework How far apart are proteins in E coli? How long (physically) is the human genome? How does that compare to the size of a typical cell?