BIOL 1020 Lecture Notes - Radiocarbon Dating, Snowball Earth, Molecular Clock
Document Summary
Cytoplasmic streaming is direction, move towards needs without a nervous system. Protists: summary: massive biodiversity, massive diversity of form and function, role as primary producers (25% of world"s photosynthesis, role as mutualists (allows termites to digest wood, role as parasites (ex. Multicellular eukaryotes: evolution of mutlicellularity (chapters 13,25: molecular clocks using dna sequences suggest that multicellularity first emerged ~1. 5 billion years ago. (know this by radio carbon dating) Less than of the time of life on earth: since then, it has evolved independently many (ca. 25?) times: evolutionary enigma why would ns favor evolution of multicellularity, what took so long to develop multicellularity, snowball earth hypothesis: Sever ice ages 750 to 580 million years ago. Most landmasses and most oceans were ice-covered. Life probably existed mostly in extreme environments (deep-sea volcanic vents, right next to the equator: problems with the cellular cooperation and complexity, advantages of multicellularity, larger size.
