A study of insects, including the large milkweed bug (above), suggests evolution may be driven by a simple and repeated genetic solution to an environmental pressure that a broad range of species happen to share.
New research by Andolfatto and colleagues published in the journal Science suggests that knowledge of a species’ genes—and how certain external conditions affect the proteins encoded by those genes—could be used to determine a predictable evolutionary pattern driven by outside factors.
Scientists could then pinpoint how the diversity of adaptations seen in the natural world developed even in distantly related animals. The researchers carried out a survey of DNA sequences from 29 distantly related insect species, the largest sample of organisms yet examined for a single evolutionary trait. Fourteen of these species have evolved a nearly identical characteristic due to one external influence—they feed on plants that produce cardenolides, a class of steroid-like cardiotoxins that are a natural defense for plants such as milkweed and dogbane.
Many different insects independently evolved the same molecular tricks to defend themselves against the same toxin suggests that studying a small number of well-chosen model organisms can teach us a lot about other species. Yes, evolution is predictable to a certain degree.