[1][2] Gould used the thought experiment of rewinding the "tape of life" to the distant past, and argued that even small changes to history would result in evolutionary outcomes very different from our world.
In the E. coli long-term evolution experiment, out of the 12 populations, only one evolved the highly beneficial trait of growing on citrate, which further experimental replays using frozen ancestral bacteria showed required particular 'potentiating' mutations to arise first.
The unique flora and fauna of isolated locations on Earth, such as New Zealand, as well as from extinct lineages such as the non-avian dinosaurs during the Mesozoic, are also examples of contingency in evolution resulting in different outcomes.
[3] In Wonderful Life, Stephen Jay Gould discusses the iconography of evolution in popular culture and the damaging effects of the march of progress on public understanding of the theory.
"[3] Gould uses the evolution of the horse to illustrate this point, as the unbroken connection between Hyracotherium (formerly called Eohippus) and Equus provides an apparent linear path from simplicity to complexity.
[3] Instead, Gould argues, we should look to bats, antelopes, and rodents as champions of mammalian evolution as they present us with "thousands of twigs on a vigorous bush" and are the true embodiments of evolutionarily successful groups.
[4] Gould presents an alternative hypothesis, however, which states that the history of life is better described as "decimation followed by diversification within a few remaining stocks",[4] represented as a pyramid with a wide base of anatomical disparity that becomes increasingly constrained by natural selection and extinction level events as time moves forward.
Gould offers the view that life during the Cambrian explosion quickly proliferated into the diversity of forms seen today due to the availability of numerous ecological niches and was subsequently decimated by extinction level events throughout geological time.
[3] For example, Ultimately, Gould explains, both the false iconography of the march of progress and our allegiance to the cone of increasing diversity have led us astray in our thinking about trends in evolutionary biology.