Lecture 02: Life Origins: Potential Exam Questions 2

Potential Question 1
Explain the difference between the morphological species concept and the biological species concept.

With the morphological species concept, individuals are grouped into species by appearance and professional judgment. Those individuals that appear similar to one another are considered one species. This concept was the origin of taxonomy. Criticisms of this method are that it is arbitrary and that it may not be able to discriminate, for example, when one species mimics another. The biological species concept defines a species as a group of actually or potentially interbreeding individuals who are reproductively isolated from other groups. Individuals must be able to produce successful fertile offspring. Shortcomings of this concept are that it cannot be used with fossils or spatially disconnected populations.

Potential Question 2
Why is there an increasing focus on RNA rather than DNA?

The origin of life required a molecule that can store information and catalyze chemical reactions. Since RNA performs both of these functions, it was probably the first genetic material. Natural selection may have operated on RNA strands, selecting those with stability and precise replication. RNA can also serve as a template for DNA synthesis.

Potential Question 3
What is evolutionary convergence?

The process in which unrelated species living in similar ecological conditions evolve to resemble one another more than their ancestors did. This suggests that evolutionary adaptation reflects ecological conditions and opportunities that shape the structure and function of organisms.

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