The organizing principle of biology

Evolution
Study Center

A reference guide to how life changes over time, plus 6 quizzes — 300 questions in all — one for each major topic the guide opens up. Every quiz breaks your score down by theme, so a poor result tells you exactly what to go back and read.

QUESTIONS
300
Across 6 topic quizzes
REPEATS
Zero
No question appears in two quizzes
GUESSABLE
No
Answer length carries no signal
TO PASS
80%
Earns a printable certificate
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The Reference Guide

What evolution actually claims, the three conditions that make selection inevitable, the forces that are not selection, six lines of evidence, how species split, the milestones of deep time, the misconceptions that will not die, and why it is a live constraint in medicine today. Every quiz here comes from a section of this guide.

Open the Reference Guide

The Quizzes

50 Questions

What Evolution Actually Claims

The narrow technical claim, the three conditions that make selection inevitable, the forces that are not selection, and the misconceptions that do most of the damage.

Start • 7 themes
50 Questions

The Evidence

Six independent lines of evidence — rocks, bodies, embryos, maps, molecules and live experiments — that had every chance to contradict each other and did not.

Start • 6 themes
50 Questions

How One Species Becomes Two

How populations stop exchanging genes — species concepts and their limits, the geography of splitting, reproductive barriers, instant plant species and the messy cases that make the boundaries visible.

Start • 7 themes
50 Questions

Milestones in Deep Time

Four and a half billion years in fifty questions, from the first microbes to the first humans.

Start • 6 themes
50 Questions

The Missing Link

Why scientists wince at the phrase — and the transitional fossils, from Tiktaalik to Lucy, that show a branching tree instead of one broken chain.

Start • 7 themes
50 Questions

Evolution and God

The history, law and sociology where evolutionary science meets religious belief — from Darwin's own doubts to Kitzmiller v. Dover.

Start • 6 themes
How these were built

Each quiz expands one section of the reference guide into 50 questions grouped into themes. Options are shuffled every time you start, and no question repeats between quizzes. Two deliberate constraints: all four options in a question are kept close in length, so the longest answer is never a giveaway; and where the science is genuinely unsettled — the oldest evidence of life, how much molecular change is neutral, whether ring species hold up as textbook cases — the questions ask for the mainstream position or an approximate range, and the explanation says where the doubt lies.