1. The Nature of Evolution: Selection, Inheritance, and History

This is a section of a university lecture, approximately the length of a lecture from Yale University's Introduction to Biology course, EEB 122. The lecture systematically organizes the core framework of evolutionary biology, focusing on the three main threads of natural selection, genetic mechanisms, and evolutionary history, and clarifies the basic logic behind the diversity of life. The key highlight is the breakdown of the abstract evolutionary theory into an understandable causal chain—from how variation arises, how advantageous traits are selected, to how species differentiate over time. The lecturer primarily uses conceptual reasoning, supported by biological examples, making it suitable for learners who want to establish a systematic understanding. It is suitable for viewers with a basic interest in biology but not satisfied with fragmented popular science; readers with a certain level of scientific literacy who wish to gain a deeper understanding of the underlying mechanisms of "evolutionary theory" can also obtain a clear framework from it. Viewing suggestion: If this is your first encounter with evolutionary theory, it is recommended to watch basic popular science videos first to establish an intuition, and then re-watch this lecture to deepen your understanding; if you already have some background, this lecture can serve as a quick path for theoretical integration.