Exam 15: Tracing Evolutionary History

Which of the following environments is thought to have promoted the dehydration synthesis of polypeptides and other macromolecules from smaller organic monomers on a prebiotic Earth?

What was the probable role of oxygen gas in the early stages of life's appearance on Earth?

How do scientists calibrate a molecular clock for a group of organisms with known nucleotide sequences?

The Mesozoic era is often called the age of reptiles.Which of the following also occurred during this era?

How is the merging of continents to form Pangaea believed to have altered Earth's environments at the end of the Paleozoic era?

The example of ocean and lake stickleback fishes indicates that morphology can be altered

Mass extinctions

The 14C:12C ratio can be used to date fossils that are up to approximately how old?

A systematist includes a lizard in a phylogenetic analysis of relationships among bird families.In this analysis,the lizard would be treated as