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Artist's depiction of an exoplanetary system, SSC Astronomy 141:
Life in the Universe
Prof. Richard Pogge, MTWThF 12:30

Unit 3: Life on Earth

If we wish to understand the nature of life on other worlds, we must start at home, with an exploration of life on Earth. This unit will review the properities of the Earth, its interior, geology, and atmosphere, and their impacts on terrestrial life. We will look at the history of Earth, and the history and present-day nature of life on Earth to understand better the physical requirements for life. Finally, we will ask what are the limits of life on Earth, and discuss our current thinking as to how life first arose.

While it may seem provincial at first to talk about life on Earth as a template for life elsewhere, this is not a statement that we expect life elsewhere to be the same as here. Far from it. A lesson from Unit 2 is that the physical processes that give rise to life on Earth operate the same elsewhere in the Universe. But that is not to say that the outcome of that process is necessarily the same. We will be exploring this theme further in subsequent sections of this class.


The lecture notes below are in Adobe PDF format, audio files are in MP3 format.
Part I: The Cradle of Life

The Earth We Stand On (Jan 13) - [Audio]

The Air We Breathe (Jan 17) - [Audio]

The History of the Earth (Jan 18) - [Audio]

Climate Regulation and Climate Change (Jan 19) - [Audio]

Quiz 1: In-Class Friday Jan 20. [study guide]

Part II: The Nature of Life on Earth

What is Life? (Jan 23) - [Audio]

Cells (Jan 24) - [Audio]

The Chemistry of Life (Jan 25) - [Audio]

DNA, RNA, and Heredity (Jan 26) - [Audio]

Extreme Life (Jan 27) - [Audio]

Part III: The Origin and History of Life on Earth

The Origin of Life on Earth (Jan 30) - [Audio]

The First Living Things on Earth (Jan 31) - [Audio]

The History of Life on Earth (Feb 1) - [Audio]

Impacts and Extinction (Feb 2)

Quiz 2: In-Class Friday Feb 3 [study guide]

Readings in Life in the Universe

Jan 13-19
Chapter 4 - we will cover most of the topics in Section 4.1 through 4.5 this week, though slightly out of order (and note that we've already discussed the parts of section 4.2 on radiometric dating in the previous unit). You can read section 4.6 on the formation of the Moon for interest, but we'll not discuss it in detail.

Jan 23-27
Chapter 5 - we will essentially follow the order of the book this week, so read all of Chapter 5, sections 5.1 thru 5.5, and treat 5.6 as an extra.

Jan 30-Feb 2
Chapter 6 - Sections 6.1, 6.2, 6.3, and 6.4 will roughly track the 4 lectures this week.

I have elected to skip section 6.5 and 6.6 in this course for want of time (I'm anxious to get back to the astronomy part of astrobiology). Besides, the subject of section 6.5 on hominid evolution is a very rich topic that the book covers in too compressed a way to give it adequate justice. Neither author is an evolutionary biologist, and it shows in this section.
I will not be strictly following the order of topics in the book, so expect a little jumping around, though in this section the book and I will track each other pretty well. All readings are from Life in the Universe, 3rd Edition, but the 2nd edition tracks the 3rd so well the readings are the same (the differences are small and quite unimportant - the 3rd edition has mostly affected the shape and physical feel of the book and added some updated bits, but the core topics and their organization are substantially unchanged). Not all topics covered in this unit are covered in the book, or in the same way, and similary there are topics the book covers that I am skipping. When in doubt when studying for the quizzes, the lectures are the primary reference, so material in the text not discussed in lectures will not be on the quizzes or final.
[ Return to the Astronomy 141 Main Page | Go forward to Unit 4 | Go back to Unit 2 ]
Updated: 2012 February 1
Copyright © Richard W. Pogge, All Rights Reserved.