A new study finds that great tits, a type of songbird, in the U. The findings, reported Thursday in Science , represent a possible empirical example of an organism evolving directly in response to human activities. The great tit, a black-and-yellow bird with a call like a squeaky seesaw, is common across Europe and is a frequent visitor to bird feeders.
Biologists have long known U. They first embarked on an ambitious investigation into the genomes—the complete sets of genes—of 2, great tits from across the U.
They flagged spots in the genomes between the two populations that were most different, which turned out to be the same spots that were the least different among the genomes of individual U. They then labeled around 30 of the genes that seemed to oust all the others and scanned the scientific literature to figure out what role these genes played in other organisms.
The scientists suspected these genes could be linked to beak length, so they measured this anatomical feature in U. They found birds with that handful of favored genes, as expected, tended to have longer beaks than their continental counterparts in the Netherlands. The researchers further backed their findings using historical data.
Ecologists at the University of Oxford, which co-authored the study, had been measuring beak lengths for 26 years, or around 13 generations for the songbird. And he thinks the evolutionary time frame is even longer than that. The researchers then scoured museum collections and looked at specimens of the birds collected since the s to confirm their findings.
Something about the U. They found that finch beak size evolved based on competition for dwindling food sources in extreme climatic conditions such as drought. But the U. After consulting with some ecologists, the team decided to test whether this natural selection had something to do with bird feeders. Whatever evolves will feel foreign and unlikely to us today — just as our current world, dominated by mammals, would have seemed improbable from the perspective of the dinosaur era.
So, what might life look like in the future? What creatures could develop in, say, million years, given what we know about life on Earth and the principles of evolution? Mimicking flowers: a new way for a bird to attract insects to eat? Credit: Emmanuel Lafont. So, it is not impossible for similarly weird and unusual creatures to evolve in future. According to Losos, the world of biological possibilities is vast, and we may not have seen everything yet.
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.
Flight has its advantages: It provides larger search areas for food, faster travel and access to places predators can't reach. But if we want big brains, we might have to give it up. Flight musculature, like a big brain, requires lots of calories to maintain. The two probably wouldn't go together, unless their combination gave us access to a very reliable new source of high-calorie food. And tools might tip the scales toward a total loss of flight. Presumably, toolmaking and tool use would be a mostly terrestrial affair, so if we're privileging in evolutionary terms the survival of corvids who are making and using tools, then we're also privileging the survival of corvids who spend a lot of time on the ground.
This also might result in the loss of crows' hollow flight bones, the trade-off being increased strength and tool use. The wings themselves, though, would most likely stay. Trees and cliff sides would probably be the nesting grounds of choice, and it would be helpful to keep limited gliding ability to access and leave nests.
Now things get weird, though, because we have to address one of the most obvious differences between primates and birds — eggs. Birds don't get pregnant. Sure, they get their eggs fertilized, but no birds actually give birth to live young.
This is rare. Getting pregnant in some form or another is common throughout other parts of the animal kingdom. Mammals do it, of course. Some sharks and other fish do it, in their own way. Even some reptiles, such as boa constrictors, also retain their eggs internally to protect their young.
Birds, however, lay eggs without exception. Even in Antarctica, where the cold makes live birth seem like an obvious choice, penguins still refuse to evolve pregnancy. Whatever else corvids would have in common with mammal people, they would lay eggs. Egg-laying would demand that corvids develop a multilayered social organization.
Individual nesting families tended by a lone mother couldn't transmit complex culture without some kind of group behavior.
Humans solved this problem by banding together into small, tightly-knit social groups, while the most important early cultural transmissions such as language came and still comes from the parent-child bond. For corvids, those parent-child connections would be much looser. Bird parents do care for their young, but newly-hatched birds bond with whatever they see first that's moving — their mother, another bird or a dangerous snake. If they banded together into tribes, they'd be imprinting on the wrong mother all the time.
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