The two species share a remarkable biological past. Museum palaeontologist Prof Paul Barrett explains how our new understanding of dinosaur evolution is transforming the way scientists think. Birds that fill the world's skies today are living dinosaurs, reminders of a distant and strange past. Decades of major new discoveries and studies have convinced researchers that there is a direct link between modern bird species and theropod dinosaurs.
Paul says, 'Dinosaurs have always sparked the imagination, but our views on these spectacular animals have changed continually through time. It began in the s with the revolutionary discovery of Deinonychus, a small predatory dinosaur that lived about million years ago.
It not only showed unique similarities to birds, but also appeared to be an intelligent, fast-moving pack hunter, rather than a slow, plodding reptile.
The discovery that Deinonychus had feathers helped to transform the way palaeontologists think about dinosaurs. New work on old specimens, and the discoveries of dinosaur and early bird species in the field, supported the idea that dinosaurs were the direct ancestors of birds.
Many features and behaviours that characterise living birds were also found in their dinosaur ancestors. Perhaps most surprising of all was the discovery of dinosaurs with feathers, completely changing the scientific community's perception of their appearance and behaviour.
The Museum's Deinonychus animatronics in the Dinosaurs gallery are sporting feathers, to give visitors an accurate idea of how these animals may have once looked. Paul says, 'Modern reconstructions of predatory dinosaurs are startlingly bird-like and would have been completely absurd to many nineteenth-century researchers. Deinonychus was a theropod, one of a group of bipedal, carnivorous dinosaurs that also included Tyrannosaurus rex.
Among those that disappeared was a knobby bone called the pisiform. Ancestral features are often visible in a developing embryo; human and chicken embryos, for example, have folds in the neck similar to those that become gills in fish.
When meat-eating dinosaurs evolved into birds, the wrist joint in the wing, between the middle and final segments, morphed again—increasing flexibility so the wing could fold back against the body. Birds also evolved a bone in the same place as the pisiform, to transmit force to the wing. Add to that an element of chance — a huge volcanic eruption or an asteroid hitting the Earth, and firm predictions become near impossible.
First, however, we must address the impact of a major evolutionary force that is already transforming life worldwide: Homo sapiens. If humans thrive for millions of years, they will have a marked effect on future evolution, and natural selection will produce new varieties of life to deal with the altered, and probably polluted, environments that we create.
Future animals may have to adapt to a more polluted world Credit: Emmanuel Lafont. On a hotter, dryer Earth warmed by humans, a lack of fresh water may also prompt novel adaptations. The frilly collars of some lizards, for example, could become very large and exaggerated to gather water in this way. In a warming planet, endothermic animals [those that generate their own heat] may have a hard time, so birds in warmer climates may lose contour feathers to prevent overheating, and mammals may lose most fur.
In this scenario, genetic engineering, biotechnology and the influence of human culture could redirect evolution down radically different paths, from mosquitoes that contain gene drives to mechanical pollinator drones. The antlers of a deer could one day take on a new purpose Credit: Emmanuel Lafont. However, there are alternative paths for future evolution: for example, our more enlightened descendants may decide to rewild nature and let natural evolution pursue its course, or humans could become extinct which was the scenario of After Man.
Extinction in particular can lead to sweeping evolutionary innovation. In essence, a mass extinction resets the evolutionary clock, argues Ward. It made space for dinosaurs to evolve and take over as the dominant land animals, an outcome perhaps as unlikely and unexpected as the take-over by mammals when they replaced dinosaurs after the Cretaceous-Tertiary mass extinction.
This article is part of a BBC Future series about the long view of our world , which aims to stand back from the daily news cycle and widen the lens of our current place in time. That changed forever with the Great Oxidation Event, around 2.
With enough time, strange and unprecedented combinations are not impossible Credit: Emmanuel Lafont. So, if humans die off, how wild and sophisticated could things get million years from now? Other marine mammals, like seals and whales, have followed this path in their transition from land-dwelling creatures to aquatic ones.
Again, these specific evolutionary paths are pure speculation. The second way to think about animals of the future is by imagining the environments of the future. Environments can drive evolution by exerting selection pressure, favoring some traits over others. For example, some birds have evolved long, pointy beaks to draw nectar out of flowers. If anything, there will likely be plastic in the environment well into the future. Of all the elements that humans have introduced into the environment, plastic waste is already ubiquitous, and remnants of it might linger for millennia if humans go on producing it as we have.
In a way, this development would kind of go full circle: Many plastics are made from petroleum, which is called a fossil fuel precisely because it derives from ancient, transmogrified plant and animal remains. So new life forms could learn to eat the leftovers of really, really old ones. Termites could be one such critter. These insects already have a gut microbiome — a collection of microorganisms that help with digestion — that breaks down cellulose.
Some fungi and bacteria, including some found in the stomachs of cows , are already able to break down plastic. The distant future is also likely to be more watery, as sea-level rise decreases the portion of the planet covered by dry land. In envisioning a world of rising seas and altered coastlines, some scientists think about how certain animals might take to living in more marine environments.
Sharlene Santana, a professor of biology at the University of Washington, considers how a bat species might evolve to live off of, and around, the oceans. She imagines a bat with a six-foot wingspan taking shape, capable of gliding like an albatross instead of flapping its wings, perhaps covering hundreds of miles in search of food or islands to roost. It might use finely-tuned echolocation to sense ripples in the water in order to detect fish. In fact, some bats already do this.
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