Ch 25 - The history of life on earth (1 slide per page)-2

Adaptive significance transcription and translation

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Unformatted text preview: mp; ER continuous in euks WHY WOULD THIS EVOLVE? Adaptive significance: - Transcription and translation separated - RNA processing prior to translation allowing control of gene expression - Removal of dif introns = dif protein Refer to Figure 25.9 (Campbell 9th ed) 45 Evolution of eukaryote morphology B. Mitochondria What is a mitochondria? Ingest aerobic bacterium and don’t digest it Why would this evolve? Aerobic bacteria receives - protection Refer to Figure 25.9 (Campbell 9th ed) Anaerobic euk receives > ATP (since more ATP produced from aerobic respiration) Evidence: - mitos have double membrane (engulfed) - extant endosymbiotic associations - e.g. some α-proteobacteria only in eukaryotes - bacteria & mitos are similar sizes - bacteria and mitos both replicate by fission - mitos have own ribosomes resembling bact ribsomes - mitos have own circular DNA (like bacteria) - mito and α-proteobacteria DNA have similar nucleotide sequences 47 Evolution of eukaryote morphology C. Chloroplast Similar evidence for the evolution of chloroplasts via endosymbiosis Secondary endosymbiosis Photosynthetic protist Refer to Figure 25.9 (Campbell 9th ed) Key Events: 48 5. Multicellularity • Independently evolved in several diff. taxa ~ 1.5 Bya (algae, kelp, fungi, animals) How evolved? • Symbiosis hypothesis • Colonial hypothesis Colonial Volvox Key Events: 49 6. Animal Diversification • Late Proterozoic • ~580 mya 1st animal fossils • Cambrian • ~535-525 mya “Cambrian explosion” • ½ of all extant phyla appear! Figure 25.10 (Campbell 8th ed) 51 Key Events: 7. Colonization of...
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This note was uploaded on 02/12/2014 for the course BIOLOGY 2011 taught by Professor Woo during the Fall '10 term at University of Central Florida.

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