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-   -   Are penguins considered dinosaurs (https://boards.straightdope.com/sdmb/showthread.php?t=886637)

Lucas Jackson 12-10-2019 10:34 PM

Are penguins considered dinosaurs
 
It’s commonly stated that modern birds are living dinosaurs and penguins are birds. So it would seem so. But based on recent penguin “missing link” find articles, they claim that penguins evolved after the dinosaurs were ‘wiped out’.

https://www.cnn.com/2019/12/09/world...scn/index.html

I realize that journalist aren’t scientist but still it made me wonder.


.

Andy L 12-10-2019 10:40 PM

It's just a journalist speaking imprecisely. By "dinosaurs" he means the popular conception of dinosaur (a big lizardy thing). But any taxonomic grouping that includes what people think of as dinosaurs also includes all birds, including dinosaurs. The fact that modern penguins evolved after the creatures that showed up in Jurassic Park were extinct doesn't matter.

whc.03grady 12-10-2019 11:21 PM

All extant bird species evolved after the (other) dinosaurs were wiped out, nothing special about penguins.

Derleth 12-11-2019 12:16 AM

"Dinosaur" is a huge family of species, grouped into smaller groups of species.

It was a huge living family before one of the Earth's bigger extinction events.

"Birds" is one of the branches of that family. They are a specific group of Theropods, which are a specific group of Dinosaurs. It's a sub-branch of a sub-branch of a bigger tree, which is, itself, a sub-branch of the massive tree of all life on Earth, past and present. You can distinguish birds from non-bird dinosaurs, but there's no way to say birds aren't dinosaurs, any more than you can say housecats aren't mammals.

You can look at this nested list to see how everything's situated. Search for "Aves" to see where all birds, past and present, are attached to the tree. Every group name with a cross in front of it is completely extinct.

septimus 12-11-2019 12:37 AM

Quote:

Originally Posted by Andy L (Post 22020094)
... But any taxonomic grouping that includes what people think of as dinosaurs also includes all birds, including dinosaurs....

Nitpick: That's true if by "taxonomic grouping" you mean "monophyletic taxonomic grouping," but in fact paraphyletic groupings are in widespread use.

If only monophyletic groupings are allowed, then insects are crustaceans, butterflies are moths, snakes are lizards, ants are wasps, whales are even-toed ungulates, trees are algae, humans are fish, all mammals are sponges, and ... all living creatures are bacteria!

Colibri 12-11-2019 12:44 AM

Quote:

Originally Posted by Lucas Jackson (Post 22020085)
It’s commonly stated that modern birds are living dinosaurs and penguins are birds. So it would seem so. But based on recent penguin “missing link” find articles, they claim that penguins evolved after the dinosaurs were ‘wiped out’.

All they mean by that is that the birds we recognize as penguins developed after the KT extinction event. It's a pretty stupid headline, since pretty much every kind of bird we recognize today evolved after the non-bird dinosaurs went extinct.

Many kinds of birds existed before the KT event, including both the lineages that led to modern birds as well as others now extinct. Actually, the most common birds before the event were those known as Enantiornithes (or "opposite birds," because their ankle joints were formed in an opposite way from modern birds) but all of these were wiped out.

The KT event appears to have wiped out all tree-living birds, and only four to six lineages of ground dwelling birds survived, including the ratites (ostriches etc), waterfowl, chicken-like birds, and the ancestor of all other birds. These lineages, especially the last, underwent very rapid divergence immediately after the extinction event, and most modern groups originated in the Paleocene/Eocene.

The article actually says that the ancestors of penguins split from their nearest relatives, the albatrosses and petrels, before the KT event, so it's not even accurate to say that penguins originated after non-avian dinosaurs became extinct. It's just that the lineage that led to modern penguins split from older kinds of penguins after the extinction event

Lucas Jackson 12-11-2019 01:42 AM

Thanks guys. And thanks for the links.

I see what you are saying Colibri. I guess I didnít stop to think that all birds today evolved after dinosaurs went extinct.

Still it seems weird to think of penguins as dinosaurs.

markn+ 12-11-2019 10:05 AM

I dunno. Penguins seem pretty dinosaurish to me, compared to things like finches and hummingbirds.

Machine Elf 12-11-2019 10:21 AM

Quote:

Originally Posted by markn+ (Post 22020711)
I dunno. Penguins seem pretty dinosaurish to me, compared to things like finches and hummingbirds.

I think geese might be the winners in the "looks like a dinosaur" contest.

naita 12-11-2019 11:04 AM

Quote:

Originally Posted by Lucas Jackson (Post 22020284)
Thanks guys. And thanks for the links.

I see what you are saying Colibri. I guess I didnít stop to think that all birds today evolved after dinosaurs went extinct.

Still it seems weird to think of penguins as dinosaurs.

I find this illustration very helpful to "unweird" it some.

https://www.xkcd.com/1211/

Colibri 12-11-2019 11:32 AM

Quote:

Originally Posted by Lucas Jackson (Post 22020284)
Still it seems weird to think of penguins as dinosaurs.

I don't think many people realize how much like birds certain non-avian dinosaurs like Anchiornis looked. And no, that's not a bird, but from a different lineage than that that led to modern birds. Some, like the bizarre four-winged Microraptor, may have been capable of powered flight. Many small feathered theropods looked much more like typical birds than penguins do.

GreysonCarlisle 12-11-2019 01:36 PM

Quote:

Originally Posted by Colibri (Post 22020237)
Many kinds of birds existed before the KT event, including both the lineages that led to modern birds as well as others now extinct. Actually, the most common birds before the event were those known as Enantiornithes (or "opposite birds," because their ankle joints were formed in an opposite way from modern birds) but all of these were wiped out.

Since the OP has been answered, I hope it's ok to ask a followup.

Why did the Enantiornithes go extinct while the ancestors of modern birds did not? Just reading the Wiki on them, they were highly diverse and widespread, with all sorts of special adaptations, and they too had the power of flight. They seem like the sort of animal that would have had at least some survivors.

Were they just out-competed by what would become modern birds, or was there something about their flight capabilities or growth rate (both mentioned in the Wiki article) that made them inefficient in the post-KT world?

Bumbershoot 12-11-2019 02:01 PM

Quote:

Originally Posted by Colibri (Post 22020947)
I don't think many people realize how much like birds certain non-avian dinosaurs like Anchiornis looked. And no, that's not a bird, but from a different lineage than that that led to modern birds. Some, like the bizarre four-winged Microraptor, may have been capable of powered flight. Many small feathered theropods looked much more like typical birds than penguins do.

I always enjoy watching the roadrunners around here; it's very easy to think of them as little dinosaurs (especially when they're hunting lizards). This one looks a lot like your Anchiornis. And this one resembles the microraptor.

Colibri 12-11-2019 02:09 PM

Quote:

Originally Posted by GreysonCarlisle (Post 22021252)
Why did the Enantiornithes go extinct while the ancestors of modern birds did not? Just reading the Wiki on them, they were highly diverse and widespread, with all sorts of special adaptations, and they too had the power of flight. They seem like the sort of animal that would have had at least some survivors.

Were they just out-competed by what would become modern birds, or was there something about their flight capabilities or growth rate (both mentioned in the Wiki article) that made them inefficient in the post-KT world?

I don't think that anything other than the luck of the draw is necessary to explain their extinction. As I mentioned as few as four to six lineages - possibly as few as six species, but probably more - of modern birds survived the KT event. There's no evidence that any Enantiornithes survived the event and were outcompeted subsequently.

As I said, all tree-dwelling birds apparently went extinct. The surviving modern bird lineages were ground birds at the time. It also appears they may have also been seed-eaters. Enantiornithes mostly still had teeth rather than beaks like modern birds, so perhaps lacked specialized seed-eaters.

GreysonCarlisle 12-11-2019 02:27 PM

Quote:

Originally Posted by Colibri (Post 22021335)
possibly as few as six species...of modern birds survived the KT event.

That really puts things into perspective. It was hell on earth, and we're kind of lucky that any higher animals survived.

Quote:

Enantiornithes mostly still had teeth rather than beaks like modern birds, so perhaps lacked specialized seed-eaters.
Makes sense. Seeds can last for a long time, even surviving fire and floods, so seed-eaters had a path to survival. Thanks!

Tamerlane 12-11-2019 02:46 PM

Quote:

Originally Posted by Bumbershoot (Post 22021315)
I always enjoy watching the roadrunners around here; it's very easy to think of them as little dinosaurs (especially when they're hunting lizards). This one looks a lot like your Anchiornis. And this one resembles the microraptor.

Behold the terror that is the Common Merganser!

ETA: The first time I saw one walking on land( something they don't do a lot of ), I thought it looked distinctly raptorial, with a triangular crested head, toothy mouth and the way the feet are set father back in the body giving it a kind of lurching, menacing gait.

Bumbershoot 12-11-2019 04:44 PM

Quote:

Originally Posted by Tamerlane (Post 22021426)
Behold the terror that is the Common Merganser!

ETA: The first time I saw one walking on land( something they don't do a lot of ), I thought it looked distinctly raptorial, with a triangular crested head, toothy mouth and the way the feet are set father back in the body giving it a kind of lurching, menacing gait.

Yikes! That and Machine Elf's goose photo are downright scary. I've seen common (and hooded) mergansers here in New Mexico, but not walking on land. We get quite a variety of water birds here, mostly along the Rio Grande. I saw a flock of white pelicans in October, just south of Elephant Butte. Bosque Del Apache Wildlife Refuge (which is north of Elephant Butte) gets a huge variety of birds migrating through.

Andy L 12-11-2019 07:19 PM

Quote:

Originally Posted by septimus (Post 22020226)
Nitpick: That's true if by "taxonomic grouping" you mean "monophyletic taxonomic grouping," but in fact paraphyletic groupings are in widespread use.

True. I was imprecise.


If only monophyletic groupings are allowed, then insects are crustaceans, butterflies are moths, snakes are lizards, ants are wasps, whales are even-toed ungulates, trees are algae, humans are fish, all mammals are sponges, and ... all living creatures are bacteria!

That's not quite true. "Butterflies" are a monophyletic group, so are "humans" - "Whales" are a polyphyletic group, though.

Colibri 12-11-2019 11:30 PM

Quote:

Originally Posted by Andy L (Post 22021912)
That's not quite true. "Butterflies" are a monophyletic group, so are "humans" - "Whales" are a polyphyletic group, though.

You misunderstand. All of the first-mentioned groups (except trees, and they are being used as a stand-in for multicellular green plants) are monophyletic. But if they are removed, the second group becomes paraphyletic. For the second groups to be monophyletic, the first groups must be considered to be part of them. (And "whales" is being used in the broad sense, to include dolphins and other toothed whales. In that sense all cetaceans are monophyletic.)

Andy L 12-12-2019 08:36 AM

Quote:

Originally Posted by Colibri (Post 22022195)
You misunderstand. All of the first-mentioned groups (except trees, and they are being used as a stand-in for multicellular green plants) are monophyletic. But if they are removed, the second group becomes paraphyletic. For the second groups to be monophyletic, the first groups must be considered to be part of them. (And "whales" is being used in the broad sense, to include dolphins and other toothed whales. In that sense all cetaceans are monophyletic.)

Got it. My apologies.

DesertDog 12-12-2019 10:50 AM

Quote:

Originally Posted by Colibri (Post 22020947)
Many small feathered theropods looked much more like typical birds than penguins do.

The Arizona Museum of Natural History where I volunteer is real proud of its Suskityrannus hazelae specimen. The articulated skeleton is in the Dino Hall on the main level and last May, a life-size model was placed at the base of the Dinosaur Mountain exhibit. Both are of a juvenile and the model is covered with "filimentous feathers" (the model maker confessed he faked them with fur). The current thinking is that a lot of young dinos were feathered for conserving body heat, but lose them as they mature.
Quote:

Originally Posted by GreysonCarlisle (Post 22021378)
That really puts things into perspective. It was hell on earth, and we're kind of lucky that any higher animals survived.

IIRC no land specie over ten kilos survived the K-T event.

Really Not All That Bright 12-12-2019 11:53 AM

Quote:

Originally Posted by Colibri (Post 22020237)
Many kinds of birds existed before the KT event...

I did not know this. Thanks!

Colibri 12-12-2019 12:31 PM

Quote:

Originally Posted by Colibri (Post 22020947)
I don't think many people realize how much like birds certain non-avian dinosaurs like Anchiornis looked. And no, that's not a bird, but from a different lineage than that that led to modern birds. Some, like the bizarre four-winged Microraptor, may have been capable of powered flight. Many small feathered theropods looked much more like typical birds than penguins do.

I should clarify that the base of the split within the maniraptors between the lineage that led to modern birds and that that led to dromeosaurs/troodontids is very fuzzy and rather arbitrary. Every new analysis seems to shift some species from one side of the line to the other. In the link for Anchiornis above, it is shown as being an early split from the combined lineage of birds/dromaeosaurs/troodontids, while in the article on Avialae, basically the bird lineage, it is shown as being a member of that group. Note that Avialae itself is pretty much a group defined for convenience by including Archaeopteryx as the first known "bird." Some studies have concluded that Archaeopteryx is more closely related to dromaeosaurs/troodontids than modern birds.

Regardless, there are still some feathered, apparently flying dinosaurs like Microraptor that were outside the bird clade.

Sailboat 12-12-2019 12:39 PM

Quote:

Originally Posted by Colibri (Post 22021335)
I don't think that anything other than the luck of the draw is necessary to explain their extinction. As I mentioned as few as four to six lineages - possibly as few as six species, but probably more - of modern birds survived the KT event. There's no evidence that any Enantiornithes survived the event and were outcompeted subsequently.

As I said, all tree-dwelling birds apparently went extinct. The surviving modern bird lineages were ground birds at the time. It also appears they may have also been seed-eaters. Enantiornithes mostly still had teeth rather than beaks like modern birds, so perhaps lacked specialized seed-eaters.

A lot of people underestimate the potential impact of contingency ("the luck of the draw") on evolution. It turns out "shit happens" is a valid evolutionary principle that helped shape biology as we know it.

Skywatcher 12-12-2019 04:16 PM

Penguins are now Snow Chickens.

:D

Chronos 12-12-2019 05:27 PM

Quote:

Quoth septimus:

and ... all living creatures are bacteria!
Nitpick: Eukaryotes are not descended from bacteria. Eukaryotes and bacteria are both descended from archae. And in fact, there are some modern archae that are more closely related to us than either are to any bacteria.

Colibri 12-12-2019 05:57 PM

Quote:

Originally Posted by Chronos (Post 22023990)
Nitpick: Eukaryotes are not descended from bacteria. Eukaryotes and bacteria are both descended from archae. And in fact, there are some modern archae that are more closely related to us than either are to any bacteria.

Actually, Eucaryotes and Archaea are both descended from a common ancestor that was descended from Bacteria (or a bacteria-like organism). The fact that they are more closely related to one another than to Bacteria indicates that Bacteria is the basal group.

Now it's arguable whether the common ancestor to Bacteria on one hand, and Archaea/Eucaryota on the other, should be called a Bacterium. But if it is, then all living things would fall within a monophyletic Bacteria.


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