1. What is the evidence that all life on 1. What is a mutation, and what Barth has a common origin? determines whether it contributes to evolutionary change? 2. How did photosynthesis make life on land possible? 2. What are two possible explanations for why very similar genes can be found in 3. What is the relationship between a bacteria and plants? population and an ecosystem? 3. Explain the molecular genetios meaning of transcription and translation. .