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Asteroid Impact Helped Create the Birds We Know Today (sciencemag.org)
sciencehabit writes: Every bird alive today can trace its ancestry to creatures that lived about 95 million years ago on a chunk of land that split off from the supercontinent Gondwana, a new study suggests. The new family tree, compiled using information from fossils and from genetic analyses of modern birds, also reveals that this lineage underwent a major burst of evolution after an asteroid slammed into Earth about 66 million years ago and killed off the rest of their dinosaurian kin.
We know that the dinosaur group filled most of the world's ecological niches, and when the Chicxulub event happened, a vast number of niches had their occupants wiped out. All we need do is assume that for any species, there is a reasonably constant mutation rate, and most mutants won't survive when there are better-adapted competitors already in a given ecological niche. If the mutant can find a different niche, though, then its chance of survival goes up a lot. So, no need to assume a "burst of evolution" when the simpler explanation is a "burst of opened opportunities", thanks to all those wiped-out competitors.
So it's the fault of that asteroid that I have to listen to that damned mocking bird all night?
I thought it was commonly referred to as roughly 65 million years ago. Have we finally reached the point where it rounds up to 66 million?
According to the article "future birds" populated western West Gondwana and didn't spread until the dinosaurs died out. In other words they would not have moved in 30 million years and then suddenly they spread wildly when the dinosaurs vanished. Looking at how animals spread today and in recent history, it looks like they spread unless there is something preventing them from spreading, such as oceans or mountains. There is no reason to think it was any different back then and either they could walk/fly around to spread or they couldn't. There could be plenty of reasons why no fossils is found in an area even though the animal existed in that area. One could be that they haven't been found, another could be that past events prevented them from being created/preserved. Lack of evidence of existence is not evidence of lack of existence.
If "birds" existed in a greater area in low numbers and haven't been found, then the evolution explosion could be explained by multiple already existing birds growing rapidly in numbers and suddenly started to appear in the fossil records. They "cheated" and started their evolution earlier than we can detect, means the rapid appearing new diverse species was more of a growth in numbers than in species.
Sure this is pure speculation, but I think the same goes for the version provided in the article. I never understood why it is assumed when something is found, it's the earliest or latest member of the species to have ever lived. Most likely neither would be the case, which mean the timeframe of species will have to be open ended, yet if you look up a species, you get a closed ended timeframe based on the age of found fossils. I don't think it can be any different (we have to write what we know, not what we assume), but we should always remember the disclaimer that no fossils is not proof of non existence, both in age and geographical location. If it was, then some species would die out and then suddenly revive themselves 2 million years later.
I thought it was commonly referred to as roughly 65 million years ago. Have we finally reached the point where it rounds up to 66 million?
That was a million years ago. You just sit and watch news day after day and suddenly the time passes without you noticing.
It is my understanding that everyone had heard...
Yeah, it was last Thursday.
systemd is Roko's Basilisk.
Was there a giant obelisk involved?
If you want news from today, you have to come back tomorrow.
1. 1% of dinos could fly.
2. Asteroid hit earth
3. 99.9% of dinos died
4. 100% of all dinos can fly.
5. ??
6. BIRDIES!
1. 1% of dinos could fly. 2. Asteroid hit earth 3. 99.9% of dinos died 4. 100% of all dinos can fly. 5. ?? 6. BIRDIES!
We luvz us our Birdies, but not all of them fly.
The shepherds did so well protecting the flock that the sheep no longer believed that wolves existed.
"Why did the birds survive and not the dinosaurs?"
You know, it was a big meteorite, so when it crashed, it shattered the Earth and dinosaurs' neck broke because of it. Birds, on the other hand, flied into the air when the shattering was coming and thus didn't receive any injury.
1. 1% of dinos could fly.
2. Asteroid hit earth
3. 99.9% of dinos died
4. 100% of all dinos can fly.
5. A few dinos get fat and heavy, or discover they are more suited to water than air.
6. 99% of all dinos can fly.
7. Chickens cannot fly, but product a wide variety of tasty and consumable products, making them easy to farm.
8. PROFIT!
It doesn't hurt to be nice.
You miss out on a large number of relatives in that scenario, komodo dragons, crocodiles etc.
If builders built buildings the way programmers wrote programs, then the first woodpecker would destroy civilization.
If something has trouble to be explained - throw in an explosion.
Religion is what happens when nature strikes and groupthink goes wrong.
I have always wondered why all dinosaurs died out, and not a single species managed to survive. It's odd. They seemingly just all disappeared, while many other reptilians managed to stay. Crocodiles for example are around from before the dinosaurs, they survived competition from dinosaurs, at least one huge asteroid impact, and competition from mammals (so far). So maybe we should look at this differently: birds ARE dinosaurs, and the birds ARE the surviving species of dinosaur.
So while most species of dinosaur died out, some species (especially the small ones that could fly - an obvious advantage to seek out habitable places, without the need of massive quantities of food) managed to survive and find a new niche, from where they started to spread and evolve in other species as they adapted to new habitats.
Insects survived, though probably also there many species went extinct.
Mammals survived, smaller than dinosaurs they can live off scarcer resources. But again I would expect many mammal species went extinct as well after the meteorite hit.
And of course the same for many, many other classes of animal and plant life.
I would hazard to guess that for every small mammal species there was foraging around, there were at least two small dino species foraging around, too. The small dino species died out, with their big cousins, whilst presumably not requiring any more "scarce resources" than the small mammals. No?