"The Tree of Life actually is peppered with tiny single-celled forms of life. Of its many branches, only three (plants, fungi, and animals) include large, many-celled organisms, and all contain microscopic ones as well."
The previous quotation is taken from the first paragraph of Chapter 9, and it outlines the core of the discussion for this week: the development of eukaryotic forms of life.
What are the main concepts that you need to know and understand for a thorough comprehension of the materials in this chapter?
- Know what distinguishes a prokaryote from an eukaryote.
- Know when eukaryotes developed, and how can we tell. Be sure to know what acritarchs are, and why are they important.
- Know what mitosis and meiosis are, and what are the consequences of both.
- Know what advantages are provided by sexual reproduction (you do not need to know all the biological details, but you need to know what you are talking about)
- Know about the wax and wane of Precambrian acritarchs. Study in particular the discussion on the four Proterozoic ice ages and their possible cause. Use these materials also to review the concepts of:
- global warming and global cooling
- greenhouse times and icehouse times
- oxygen and carbon sinks
- fossil fuels burial vs. fossil fuels burning
- Small, shelly fossils mark the base of the Phanerozoic (Cambrian). Between the Varangian ice age (590 Ma) and the Cambrian (550 Ma) are the oldest pluricellular animal fossils. Know about the Ediacaran Fauna, including the four points detailed on pages 261 and 263.
Please note:
All quiz questions will be from chapter 9 of Cradle of Life only. This chapter completes our study of the biological evolution of life on Earth.
Please be aware that these materials are also summarized in our textbook (Earth System History) in chapter 11 (pages 262-270) and in chapter 12 (pages 278-286). You already reviewed those materials and you are encouraged to browse them again for reference; I will also list them in the study guide for the final exam.
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