Review worksheet covering IB Biology content on the Origins of Cells (Topic 1.5)

1. IB Biology: Origins of Cells (1.5) Review NAME:
1. In 1953, Miller and Urey performed a famous experiment that lent weight to the spontaneous generation hypothesis for the
origins of life on Earth:
a. Outline the central idea of the spontaneous generation hypothesis:
b. What aspects ofthe early Earth’s conditions did Miller and Urey include in their model?
c. Describe the Miller-Urey experiment and its findings:
2. Miller and Urey’s work showed how the first organic molecules might have formed, but the origins of the first cells, which
emerged on Earth 3.5-3.6 billion years ago, pose further questions:
a. Why do scientists hypothesize that simple organic molecules assembled into polymers around thermal vents?
b. Describe how the first cell membranes may have formed:
c. Identify at least two reasons that scientists believe RNA is was the most likely genetic material of the first cells:
3. What is explained by the Endosymbiotic Theory?
4. Annotate the diagram, below, to describe the theorized stages of endosymbiosis:
5. State at least four pieces of evidence that support the endosymbiotic theory: