Biology 1001A Lecture Notes - Phylogenetic Tree, Hominidae, Bacteria
19 Nov 2012
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Document Summary
First cells had appeared: 3. 5 billion years ago. First eukaryotic cells had appeared: 2. 5 billion years ago. Main characteristics distinguishing eubacteria, archaea, eukaryota domains life. Archaea: unicellular organisms that live in extreme conditions (circular dna: different rrna sequences. Eukaryota: contains both unicellular and multicellular organisms (linear dna) Hgt: transfer and incorporation of one organism"s/species dna into the dna of a different organism or species. Contrasts dramatically with the vertical transmission of genes from generation to generation (e. g. , plasmids or transposons) Thus makes it challenging to recreate universal tree of life. Most recent common ancestor (mrca) for groups, given a phylogenetic tree (branching points on tree of life) Mcra of humans estimated to be about 3,000 years ago: chimps and bonobos. Old world and new world monkeys: tarsiers. Lemurs and lorises; mcra of all primates (65 million years ago end: cretaceous mass extinction: rodents and rabbits, laurasiatheria.
