How do we really know where we came from?

How do we really know where we came from? Science tells us one thing yet others say different? What information do we trust? Can we know for sure? Examine this hot button issue about the origins of life on Earth.
Links to start with:
http://www.nationalacademies.org/evolution/
http://www.answersingenesis.org/tj/v15/i2/textbooks.asp
grading rubrics:

Presents a clearly focused main idea that addresses the topic

Develop the position with compelling reasons and or persuasive examples

In depth summary of personal opinions and effective and reasonable solution

Express Ideas fluently and precisely using effective vocabulary and sentence variety

No grammatical or spelling or punctuational errors. APA style with sources sited