EARTH 7 Lecture Notes - Lecture 3: Lynn Margulis, James Hutton, Purple Bacteria
Document Summary
& brief history of life: different places have exposed rocks of different ages, the timescale was developed by incomplete, but overlapping sections throughout the world. James hutton: uniformitarianism, (cid:862)prese(cid:374)t is key to past(cid:863) Lord kelvin: predicted the earth cannot be older than 20-40 ma. A brief history of life ~ 3. 5 ga: stromatolites from warrawoona, australia 3. 5 billion years ago were the first good evidence of life. Prokaryotes vs. eukaryotes: prokaryotes contain a cell wall, are less complex, and contain floating dna, eukaryotes contain organelles (i. e. mitochondria and chloroplasts) and have a nucleus with dna within. Cellular membranes: chloroplasts and mitochondria have an inner membrane made by organelles and an outer membrane made by the host cell. Chloroplasts and mitochondria replicate independently of the host cell: cannot be regenerated by the cell if lost, have their own dna. When dna and rna of chloroplasts and mitochondria are analyzed, they nest within the cyanobacteria and purple bacteria.
