Book Review: What On Earth Evolved? 100 Species That Changed the World by Christopher Lloyd

Review by Sid Perkins

Throughout Earth’s past, innumerable species have come and gone without making much of a mark, but a select few have lived long and prospered indeed. In this eloquent and richly illustrated volume, Lloyd, who also authored the planetary history What on Earth Happened?, compiles a veritable who’s who of organisms that he contends are the 100 most important species or groups in the planet’s history. (Hint: Humans are high on the list, but they don’t top it.)


Half of those in the tally evolved before humans became a major influence on species’ fates about 12,000 years ago. Members of the second, more recent group owe much of their success to the ability to accommodate or satisfy human needs. Lloyd uses five criteria to rank organisms’ influence on the planet’s history: their longevity as a species, the size of their range, their evolutionary impact, their environmental impact and their impact on human history. Species or groups included in this esteemed list range from algae and cyanobacteria that have been oxygenating Earth’s atmosphere for billions of years to a relatively recent upstart, Homo sapiens.

From tales of trilobites and T. rex to cotton, cannabis and coffee, thought-provoking biographies of these 100 shapers of Earth’s history take readers on an engrossing journey from the beginning of life to the present day. The book chronicles the sometimes complicated interrelations between and among those organisms. Though some may quibble with his rankings or criteria, Lloyd’s aim, as he notes, is not only to inform and entertain his readers but also to stimulate debate about the place of humankind in nature.

Bloomsbury USA, 2009, 416 p., $45.