Which phrase encapsulates the central idea of common ancestry for species?

• A. Descent with modification from common ancestors
• B. Spontaneous generation
• C. Intelligent design
• D. Catastrophism

Answer: (A)

Descent with modification from common ancestors captures how species are related through lineages that pass traits from one generation to the next while gradually changing over time. This phrase combines two key ideas: that different species come from shared ancestors (descent) and that they accumulate differences (modification) as they diverge. It’s the language that underpins the whole concept of a family tree of life, explaining why we see similar body plans and genetic similarities among related groups.

Spontaneous generation isn’t about lineage or inheritance of traits across generations; it’s an old idea about life arising anew. Intelligent design posits a designer rather than a natural, branching lineage. Catastrophism focuses on large, sudden geological events, not the biological connections among living beings.