Download Chapter 17 - Origin of Life

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Unit 4: Evolution
Chapter 17 The Origin of Life
1. Observe the photo on p. 436 of a sea dragon. Based on only
the photo, to what organisms do you think this is related? Upon
what do you base your answer ?
2. Observe the picture below, similar to the one on p. 438 in
your textbook.
These are Stromatolites, microbial mats, each about 1 meter
across, found in Australia. They appear as rocks because they
also have hardened sand and precipitated minerals. Some date
back almost 3 billion years. What microbe would be involved in
these “rock” building micromonoliths?
3. What was the Big Bang? What evidence support this?
According to the diagram on the following page, how do
astronomers know that the universe is expanding?
Hubble telescope
4. Scientists have estimated Earth to be 4.6 billion years old.
How long did it take for life to form on Earth? What was the
first life form?
5. Read Biological Challenge on p. 442. How is dating obtained
using C-12 and C-14? How many years can be accurately
measured using C-14 radioisotopes?
6. If C-14 has a half-life of 5,730 years, how many half-lives will
a substance go through that has been dated to about 29,000 yrs
of age?
The diagram below depicts the nebular hypothesis, a hypothesis
to explain the origins of our solar system. Explain what you
understand from it.
7. What was early Earth like? What evidences do you have to
support this?
8. What gases were probably in Earth’s early atmosphere? What
evidence can you use to support your answer?
9. Explain why free oxygen gas probably was not in the early
atmosphere of Earth.
10. What are the three major explanations for how life formed
on Earth?
11. There were two theories of chemical evolution: OparinHaldane and Miller & Urey. Explain both.
12. It is known that amino acids are found in meteorites,
comets and asteroids. Give possible explanations of their origins
AND possible explanation of its significance to the formation of
life on Earth.
13. What is the importance of clay in constructing life forms?
14. Did life begin in a DNA or RNA world? Defend your answer.
15. What is a ribozyme? How does this enhance your
understanding of origins of life?
16. Exobiology is synonymous with astrobiology. Define it.
17. Why are viruses considered to be less than an organism?
Why do they not subscribe to the cell theory?
18. Label the parts of the T-series bacteriophage, a virus that
infects bacterial cells.
19. Methanogens belong to a domain of life called Archaea,
known as the extremophiles. What does their name suggest to
you? How do they obtain their energy?
20. What is the evidence that the oldest fossils were
autotrophs?
20. What is the endosymbiosis theory as proposed by Lynn
Margulis?
21. What evidence supports the idea that mitochondria and
plastids originated from free-living prokaryotes?