UNSW's surprising study on the behavior of unrelated lizards from different regions of the globe has shown that evolution can result in different species learning the exact same skills.Ecology Letters' study reveals how Anolis lizards in the Caribbean and Draco lizards in Southeast Asia have overcome the problem of communicating to each other in order to protect their territories and attract mates.It was found that males of both species engage in elaborate head bobs and push up displays. They also rapidly retract and extend their conspicuously coloured dewlaps, or throat fans, especially in low-light habitats or areas with wind-blown vegetation.Because lizards live in the same habitats of grassland and rainforest, they face the same challenges when communicating with potential mates or enemies in visually noisy environments.Amazingly, they have developed the same strategy to deal with the same selection issues, Dr Terry Ord, the Evolution & Ecology Research Centre, UNSW School of Biological, Earth and Environmental Sciences, says.His research shows that this example of two unrelated species of lizards showing similar behaviours indicates that natural selection drives evolution to the same set of adaptive outcomes over time.AdvertisementDr Ord explains that "the surprise is that lizards from both groups have developed remarkably similar displays to communicate, but they also adjust the production of those displays to suit the prevailing conditions at the time," Dr Ord said.This means that they will display the movements at a faster speed or for a longer time as the viewing conditions change."Really, there should have been essentially innumerable methods these lizards could adapt their displays to remain effective. And there are strong evolutionary predictions to support this."Dr Ord stated that this study shows how natural selection drives similarities between species.He calls this convergent evolutionary -- an independent origin of similar adaptations.AdvertisementHe says, "It seemed like these types of common, convergent adaptations are only really occurring among species that are close-related in some capacity.""The explanation for this is complicated. It rests on adaptations that are built on traits that a species already has.""The longer species have been independent, the less likely they are to develop the same adaptive solutions if exposed to the same environment change."He says that this study highlights what evolutionary ecologists have argued: that natural selection can overcome the "baggage", or past history, to produce the same adaptations.He says, "If arm-waving is the most efficient solution to some environmental change, then natural selection would eventually lead to its evolution instead of a subtler (less effective) modification of an existing vocal call.""Evolutionary biologists love convergent evolutionary because it provides multiple examples of the same adaptation being developed time and again in very different animals. What is the answer?It tells us about the evolutionary challenges faced by these animals, and how they have overcome them.This study shows how communication strategies have developed independently over hundreds of millions of year between groups that have been apart for many years.Dr Ord claims that there are striking similarities between communication strategies in maintaining an effective communication system under noisy conditions. These communication strategies have evolved in many forms in insects, fishes, frogs and mammals.Dr Ord explains that you can increase the volume of calls if there is a lot of background noise or extend the duration of those calls, or even vibral signals by spiders."It is amazing that other animals have developed the same adaptive strategies.
