Discussion Questions 4/28

1. In "Alien Evolution," Shoshana Tobias hooks the reader's interest by creating a story about a fictional planet set several years in the future. Through the character of Jay, the reader is taken vicariously on an expedition to the foreign planet to determine its habitability.

2. This method could be used in our own case study by presenting a fun story but at the same time using facts and figures to back it up. It is not often you see science presented in this fashion, but I think it's a refreshing change of pace. It is definitely something to consider.

3. Part 1:

1. The Late Pre-Cambrian environment was a time when Earth was going through rapid and major changes, both in its physical and chemical composition (Zimmer, 229). It was at this time that oxygen levels began to drastically rise (Zimmer, 229), setting up the conditions for the massive expansion of life to take place.

2. Ediacaran organisms were similar to invertebrates, and are believed to have evolved on their own. http://www.paleoportal.org/index.php?globalnav=fossil_gallery&sectionnav=taxon&taxon_id=131

3. Earth's Pre-Cambrian is similar to P-L5's initial environment and organisms because the oxygen level was very low (5%), just like it was on Earth during the time period.

4. The "Cambrian Explosion" is when the levels of oxygen on Earth increased, which led to a drastic increase in life and biodiversity on the planet.