
Baby Bird from Time of Dinosaurs Found Fossilized in Amber - billconan
http://news.nationalgeographic.com/2017/06/baby-bird-dinosaur-burmese-amber-fossil/
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colordrops
Considering that some dinosaurs had feathers and looked a lot like birds, at
what point were birds considered "birds" and no longer dinosaurs?

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derefr
The Wikipedia description is as good as any:

> [Birds] are ... characterised by feathers, toothless beaked jaws, the laying
> of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a
> strong yet lightweight skeleton.

Notice that when you put all of those traits _together_ , you get the ability
to lead a lifestyle centered around long-range migratory flight.

One or a few species evolved this particular set of traits, which gave them
the ability to forage incredibly long ranges in search of food, in a landscape
that was—at the scales other dinosaurs could travel—increasingly inhospitable
to life. This small set of species then took over the habitats of every other
dinosaur species as they died out, and then speciated into all modern birds.
It was a sort of evolutionary bottleneck point.

In other words, "birds" are essentially _defined as_ the set of theropod
species that survived the K-T extinction. Birds _happen to_ all have many
unique traits in common, because these traits were adaptive through the rapid
change of environment that killed off the other dinosaurs.

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laumars
edit: too late to delete. I misunderstood the OP.

Appologies.

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derefr
That was kind of the point of my definition, actually—it's easier to predict
what type of thing is a bird if you think of "bird" as "the clade rooted on
all the theropods that fit through a particular evolutionary sieve" rather
than a category with certain characteristics. Not all modern birds have those
characteristics. But those characteristics are what allowed the prototypal
"birds" to survive where other dinosaurs did not. Their descendants went on to
adapt in various other ways, but we still consider them all "birds" for
reasons of _genetic_ lineage back to those original birds.

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laumars
Sorry, I misunderstood you and thought your "flight" point was meant to be
valid for current species as well as the early incarnations. Appologies.

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nickhalfasleep
It points to a very difficult time to be a baby bird if you are born with
nearly flight ready feathers.

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j9461701
Precocial young don't necessarily imply a difficult time, it's simply one of
several strategies for successful reproduction. Do you minimize the chances
your young are preyed on in the nest by A) Building a very well hidden nest
and guarding it well or B) Ensuring the nest is only needed for a few days?

Additionally, altricial species tend to be much more intelligent so that's
another factor to weigh in on which evolutionary strategy is optimal for a
given species.

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ComputerGuru
> Additionally, altricial species tend to be much more intelligent so that's
> another factor to weigh in on which evolutionary strategy is optimal for a
> given species.

That's up for debate, as koalas and kangaroos challenge that notion. Then
again, those are both marsupials from Australia; it's possible they are
exceptions for some reason due to other, environmental factors.

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j9461701
Ecological observations tend to be general trends rather than absolute laws,
as evolution is a messy and gradual process. Cetaceans are another example of
a group that violates the trend, being both extremely intelligent and their
enviroment necessitating extremely precocial young to avoid their offspring
drowning.

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majestik
Pretty sure this was the start of Jurassic Park's plot

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aerodog
[https://en.wikipedia.org/wiki/Ancient_DNA](https://en.wikipedia.org/wiki/Ancient_DNA)
\- it looks like scientists gave up hope of retrieving dna from amber, but
there are recent examples of extracting dna from ~ 1 million year old
specimens...

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sr2
But even if they had dino DNA, would they be able to reconstruct a dino from
it, like they're trying to do with mammoths?

[0]: [https://www.theguardian.com/science/2017/feb/16/woolly-
mammo...](https://www.theguardian.com/science/2017/feb/16/woolly-mammoth-
resurrection-scientists)

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pipedreams2
I sure hope so

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howfun
How much can this amber sell for?

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rnprince
This amber contains Aerodactyl?

