BIOL1012 Lecture Notes - Lecture 9: Mitosis, Digestion, Phylogenetic Tree
Document Summary
Eukaryotes are relatively young: oldest eukaryote fossils. Hotly debated: oldest multicellular eukaryote fossil is. Bangiomorpha pubescens: 1. 2 billion year old fossil, cellular differentiation apparent (holdfast, evidence for reproduction, likely a red alga and found in canadian. Why is this important: in a word becoming increasingly aerobic, symbiosis between could be mutually bene cial, an anaerobic heterotroph host could use nutrients derived by a photosynthetic endosymbiont. Key innovations: cytoskeleton (internal & external movement, compartments (s:v ratio; maintain varied internal environments, endomembrane system, mitochondria & chloroplasts, mitosis, diploidy, meiosis & sex. Cytoskeleton: maintain shape without walls (aids movement & exibility, position organelles relative to each other & plasma membrane, cell components, new movement. Endomembrane system: endomembrane system: endoplasmic reticulum (er), nuclear envelope, golgi, etc. , Figure 6. 15: invagination of the plasma membrane. Mitochondrion: primary endosymbiont hypothesis: a lineage of early eukaryote heterotrophs engulfed bacteria, but rather than digesting them a symbiotic relationship was established.
