Which road is the chicken crossing?

[eggomaniac]

This is not a homework question, not a theory, not a debate about evolution v creation, don't turn into such, please.
I'm just curious; is the chicken an animal that is evolving into a flighted bird, or a flighted bird that is evolving into a quad? OR are there some species of chickens going one way and others the other way? What will those wings be used for in the future?
I'm not a biologist, so I am hoping there will be scholarly information.
Mods, if Posters say things like 'twaddle' and 'chicken wings with beer could you just remove those Replies, instead of closing the Thread!?
If the chickens were flighted birds, and that is only one possibility, as they could be evolving towards flighted animals, did they just get conditioned by apes who could keep them in toasty barns?
Is this simple 'biology' that the great biologists and evolutionists have already explained?
[Really - scientific and scholarly Replies or not at all - we shall see]
It's either A. a completely analyzed and documented question or B. an interesting scientific curiosity.

 

[lisab]

It's my understanding that birds who find themselves in environments where there is little advantage to flight, lose that capability. Think dodos and emus. Flying is expensive, biologically speaking.

From the wiki on the Red Junglefowl (the ancestor of today's domestic chicken):

Flight in these birds is almost purely confined to reaching their roosting areas at sunset in trees or any other high and relatively safe places free from ground predators, and for escape from immediate danger through the day.

http://en.wikipedia.org/wiki/Red_Junglefowl

I used to raise hens, and that's about how much they could fly, too. But I doubt very much that the birds you find in factory chicken farms could fly anything close to that much. In fact I'd be surprised if they could lift their weight off the ground even for a second.

So I'd suggest that the domestic chicken's flying ability is decreasing, given these facts:

• its ancestor wasn't a great flier to begin with, and
• modern farming methods are reducing the need for flight the flight.

And I didn't even mention beer .

 

[nucleargirl]

I'm just curious; is the chicken an animal that is evolving into a flighted bird, or a flighted bird that is evolving into a quad? OR are there some species of chickens going one way and others the other way? What will those wings be used for in the future?

If the chickens were flighted birds, and that is only one possibility, as they could be evolving towards flighted animals, did they just get conditioned by apes who could keep them in toasty barns?

ok, so to answer question 1, I would say neither. The chicken is a perfectly evolved animal for its environment as it is - unless its environment changes (e.g. chickens find themselves in the wild, or some intraspecies or interspecies competition puts pressure on chickens to change in some way to enable them to survive better, these are just examples of environmental change) then there is no need for the chicken to change in any way.

question 2, like Lisa said, they lost the ability to fly because of human artificial selection over centuries. Humans selected for offspring of the red jungle fowl for ones that didnt fly (I'm guessing here cos I'm no chicken expert, but it makes sense: less flying = more energy for growth) so the chickens we see today don't really fly. So yes, humans made the chickens the way they are by artificial selection.

um, I know that we belong to the apes, but because 'apes' also has a derogatory meaning, you are putting your intentions at risk of misunderstanding by others by calling people 'apes'.

 

[nucleargirl]

yeah, evolution is actually a simple process, that's why it is so amazing, and why Darwin is brilliant to have discovered it - its often easy to complicate things, and under the obligatorily religious times he lived in, I think it would have taken a lot of brains and guts to think of evolution and then stand by it like he did.

 

[nucleargirl]

I mean that the process itself (as I understood it) is simple, but the implications of evolution are ginormous! Its pretty much everything we see around us!

so, I would recommend (again) that you read about evolution. if Darwin's book is too hardcore, try Richard Dawkins, basically, the more you read about it, the more it makes sense.

try this: http://www.newscientist.com/article/dn9953-instant-expert-evolution.html

 

[eggomaniac]

Lisab; Dodos and Emus, Egads I wasn't even thinking of penguins, ostriches, kiwis. duh me
I'm trying to get my mind around the evolution thing. When you say ancestors of chickens, I'm thinking ancestors of ancestors of ancestors.
All of the modern thinking has the flightless birds losing the ability. Now, think about this, all of the very first birds had to, logically, be flightless animals who evolved into flighted ones.
We, apes and all, came from the primordial muds, not the primordial clouds, unless there was some kind prevailing wind that kept simple creatures airborne for millions of years, developing that way.
Given, the hypothesis, birds evolved from flightless creatures, likelihood is 99.9999%; then A. I would like to see the family tree. I have observed great scientists, like Dawkins don't hang out here but I am hoping someone has contact with a bright professor, or two, or links where this question has been dealt with.
B. Why is it 100% of the flightless birds evolved from flighted, when the other million bird species went the other way? Maybe, just maybe, some of the, present day, flightless birds are just late bloomers and are, also, evolving towards flight. Maybe some used to fly but maybe some will fly anon, like the rest learned, or evolved, to do.
[NG, I'm not calling anybody an ape, on the street; in this Forum I'm just trying to use the correct terminology. Krauss and Dawkins calls us apes.]
But let's stick to this topic of bird flight, please.
Have evolutionists, based on the hypothesis all flightless birds used to fly, categorised any others who are on their way to flightless? Seems odd if a couple of dozen out of millions 'evolved' this way, there should be at least 1000 others following the process, eh?

 

[NobodySpecial]

B. Why is it 100% of the flightless birds evolved from flighted, when the other million bird species went the other way?

Partly this is a question of classification, a flightless animal that is now flightless, never having evolved into a bird is called a lizard - you could argue that some species of flying lizards are on their way to evolving into 'birds'. But being able to fly or not isn't a characteristic of a bird.

The same thing happens with sea mammals, whales, dolphins, seals, manatees etc evolved from land mammals that evolved from reptiles, that had evolved from fish - that of course lived in the sea.
That cetaceans and pinnipeds make a good living splashing around in the water today doesn't have a lot to do with them having evolved from fish 250million years ago. The sea just has a lot of advantages as a place to live.

 

[madcat8000]

Well here's a well refrenced site with lots of interesting pictures and videos: http://people.eku.edu/ritchisong/554notes1.html

All birds share the raptor base model with some modifications.

Feathers are truly ancient as they exsist in the reptile line in alligators, whtich predate the dinosaurs: http://www.ncbi.nlm.nih.gov/pubmed/17784647

And birds start growing teeth until their genes shut them off whitch draws another line back to their raptor lineage: http://www.timesonline.co.uk/tol/news/world/article1138908.ece

Chickens are animals that are responding to the selective pressures we have initiated through domistication. Unluckly for them in a few thousand more years that will probably lead them to a dead end. They have no natural place in nature anymore and probably won't make it a few generations after we stop supporting them.

 

[DaveC426913]

Given, the hypothesis, birds evolved from flightless creatures, likelihood is 99.9999%; then A. I would like to see the family tree.

Yes. Read up on Archaeopteryx. It is a precursor to flighted birds.

In a nutshell, the prevailing theory is that lizard-like creatures evolved featherlike extensions on their limbs.

When escaping from predators, these featherlike extensions allowed them to glide slightly father than their featherless siblings. Fast forward 10 million years and you have an ecology where feathered lizards have persevered where featherless ones have been eaten.

Here is the critical thing to understand:
These featherlike extensions did not initally evolve as gliding surfaces; they evolved for some utterly unrelated reason - perhaps as a mating display, or a downy coat for winters. It is only a side-effect that they ended up serving the bird in a totally different way when its environment changed.
This is key to understanding evolution.

B. Why is it 100% of the flightless birds evolved from flighted, when the other million bird species went the other way?

Because evolution is directionless. It is often driven by environmental and geographic differences. Percurors to penguins were able to fill a niche in the antarctic. The niche is fish. Flight is useless to a creature that swims to survive.

Maybe, just maybe, some of the, present day, flightless birds are just late bloomers and are, also, evolving towards flight.

No. Evolution is not "headed" anywhere; it has no program.

Current flightless birds will re-evolve flight if and only if it gives them an advantage (often when their environment changtes, or a niche is left open).

Have evolutionists, based on the hypothesis all flightless birds used to fly, categorised any others who are on their way to flightless? Seems odd if a couple of dozen out of millions 'evolved' this way, there should be at least 1000 others following the process, eh?

It's about environment and geography.

Note that it works the other way too. Lizards are not the onlyt creature to have discovered the untapped niche that is the shy.

Tiny mammals have managed to do so as well. Bats. Completely different creature, put in the same environment, finds the same solution. All those mosquitos, just waiting around for some little mammal that can drop out of a tree and glide long enough to snatch them up.

 

[Evo]

We, apes and all,

Twice now I've seen you refer to apes and evolution. You are aware that we are not descended from apes?

As lisab pointed out, chickens have been bred for specific qualities, and flight is not one of those qualities.

There is no reason to believe that the current flightless birds ever flew or flew well, so they did not necessarily go from flying to not flying.

 

[eggomaniac]

Chickens are animals that are responding to the selective pressures we have initiated through domistication. Unluckly for them in a few thousand more years that will probably lead them to a dead end. They have no natural place in nature anymore and probably won't make it a few generations after we stop supporting them.

I'm totally impressed by the great Replies, it was better than I hoped, and now have hours of reading.
[A bit of levity, Madcap, the chickens saw the 'dead end' I am assuming you mean, so they started laying real crappy eggs to force us to do free range. By the time we are extinct they will soaring like pigeons. I wonder what Darwin would have thought of the pale yellow super store eggs?]
One question, is it 'possible' one or more of the flightless birds is evolving towards flight? The penguins might want to consider it.

 

[eggomaniac]

Twice now I've seen you refer to apes and evolution. You are aware that we are not descended from apes?

As lisab pointed out, chickens have been bred for specific qualities, and flight is not one of those qualities.

There is no reason to believe that the current flightless birds ever flew or flew well, so they did not necessarily go from flying to not flying.

hmmm...
I was only going by a book from the 60's by Desmond Morris, The Naked Ape
Wiki >
Morris first came to public attention in the 1950s as a presenter of the ITV television programme Zoo Time,[2] but achieved worldwide fame in 1967 with his book The Naked Ape.[3] The book is an unabashed look at the human species, notable for its focus on humanity's animal-like qualities and our similarity with apes, and for explaining human behaviour as largely evolved to meet the challenges of prehistoric life as a hunter-gatherer. Reprinted many times and in many languages, it continues to be a best-seller.
And there is this http://www.gate.net/~rwms/hum_ape_chrom.html
"""assembled a series of references and abstracts that document striking evidence for the common ancestry of humans and the great apes"""
>>>> .like your the Mod and all so if its against the rules to say we are apes, I will stop.
If there is info we are not, like you say, I would like to read about it, is there threads on that Topic?

 

[NobodySpecial]

You are aware that we are not descended from apes?

Not only are we descended from apes - we are apes.

There is no reason to believe that the current flightless birds ever flew or flew well, so they did not necessarily go from flying to not flying.

It's pretty likely that the ancestors of chickens once flew. The odds that all their ancestors back to lizards were flightless, and yet evolved feathers, chest bones, wings and beaks - all adapted to flight - but never flew is rather unlikely.

Although the immediate ancestors of domestic chickens were ground dwelling fowl that if they flew at all it was probably limited to fluttering up into trees to sleep

 

[eggomaniac]

just for the record, pf Mentor changed the Topic from birds, flight, and evolution, to apes and man,,,,,
as the OP I don't mind if it goes that way, as the leads for information I was looking for on THIS Topic came out.
I would like to hear from others about whether we are monkeys or apes. It appeals to my curiosity. I cannot swear, but I am sure I heard Krauss and or Dawkins, in the You Tube discussions that led me to the Site, say we are apes...
Dang... it would take awhile to find those 'talks' again.
I am sure IF Dawkins did say it, well then it would be OK! and class anybody disagreeing with him as an anti evolutionist.

 

[eggomaniac]

There is no reason to believe that the current flightless birds ever flew or flew well, so they did not necessarily go from flying to not flying.

on this Topic, that is a statement which makes sense. That is the question I will be looking into from all of the great links supplied. If flightless birds are evolving towards flight, like all the other species did, that would make for a pretty good 'proof' of evolution.
Notice on Wiki it 'conjects' that these birds 'lost' their flight ability, but it has the 'citation needed' sticker.
"""It's believed by some[citation needed] that most flightless birds evolved in the absence of predators on islands, and lost the power of flight because they had few enemies — although this is likely not the case for the ratites; the ostrich, emu and cassowary, as all have claws on their feet to use as a weapon against predators."""

 

[Evo]

Not only are we descended from apes - we are apes.

No, we are not descended from apes.

1. Did we evolve from monkeys?

Humans did not evolve from monkeys. Humans are more closely related to modern apes than to monkeys, but we didn't evolve from apes, either. Humans share a common ancestor with modern African apes, like gorillas and chimpanzees. Scientists believe this common ancestor existed
5 to 8 million years ago. Shortly thereafter, the species diverged into two separate lineages. One of these lineages ultimately evolved into gorillas and chimps, and the other evolved into early human ancestors called hominids.

Hopefully this makes it clearer to you.

http://www.pbs.org/wgbh/evolution/library/faq/cat02.html

It's too late to try to dig something else that sums it up clearly in a paragraph.

 

[eggomaniac]

Humans share a common ancestor with modern African apes, like gorillas and chimpanzees. Scientists believe this common ancestor existed
5 to 8 million years ago. .

So we're not apes, we are apoids? How spell semantics?
Watch Dawkins call us apes.
argue with him about it.

and this>>>
http://richarddawkins.net/articles/4121-elaine-morgan-says-we-evolved-from-aquatic-apes

 

[Ken Natton]

Eggomaniac, if I might try to help you to grasp what it is, it seems to me, that you are missing: I always think that the whole misunderstanding about the common ancestry of apes, of primates or of whatever other point you want to take in the complex phylogenetic structure has the wind taken out of its sails by this little astonishing evolutionary fact: There is powerful evidence, from microbiology, that human beings have a common ancestor with fruit flies. Now grasp it straight away, that common ancestor was neither fruit fly nor human. It might have borne no obvious morphological resemblance to fruit flies or human beings. And yet, whatever is common between modern fruit flies and modern humans – and there is a great deal more commonality between us than you might realize – existed in that common ancestor. There are any number of vastly different modern species who have a common ancestor, if you go far enough back down the evolutionary chain, but whose common ancestor would not belong to the modern classification of either modern species. So, the obvious morphological similarities between human beings and any other primate species is pretty powerful evidence that our common ancestor is much more recent than is human beings common ancestor with fruit flies. But that common ancestor still existed an awfully long time ago, and there is no accuracy at all in the idea that human beings are descended from any other modern primate.

And the key point in answer to your original post was explained in close detail by DaveC426913 in post #9. You should pay very close attention to that post. It is a vital point to grasp that no evolutionary change that has ever occurred in any species did so with any specific purpose. Those that happened to give the organism a selective advantage have survived and propagated through the species by the process of natural selection. But penguins are evolving neither in the direction of flightlessness or flightedness. They have developed their superb ability to swim because of the powerful selective advantage that ability has in the environment in which penguins live. But none of the incremental changes that occurred in their ancestors did so with the specific goal of becoming such superb swimmers. Evolution can’t do that.

 

[DaveC426913]

...human beings have a common ancestor with fruit flies. Now grasp it straight away, that common ancestor was neither fruit fly nor human.

...
So, the obvious morphological similarities between human beings and any other primate species is pretty powerful evidence that our common ancestor is much more recent than is human beings common ancestor with fruit flies. But that common ancestor still existed an awfully long time ago, and there is no accuracy at all in the idea that human beings are descended from any other modern primate.

Worth repeating.

You have no trouble understanding that the common ancestor of humans and fruit flies was neither. We did not descend from fruit flies.

Likewise, the common ancestor of humans and apes was neither. We did not descend from apes.

 

[DaveC426913]

There is no reason to believe that the current flightless birds ever flew or flew well, so they did not necessarily go from flying to not flying.

This would astonish me.

Are you suggesting that no ancestor of modern penguins could fly?

I would bet a lot of money that no ancestral birds developed flight wings yet could not fly. It is only an adapation after the achievement of flight - and the extinction of any flightless prespecies - that birds found other niches where their flight withered.

In fact, I'm not sure it makes sense to call the flightless precursors of birds 'birds' at all. They would be ... lizards. I submit that the definition of birds is that it is that precursorial line of lizards that did develop flight.

 

[cosmos 2.0]

This would astonish me.

Are you suggesting that no ancestor of modern penguins could fly?

I would bet a lot of money that no ancestral birds developed flight wings yet could not fly. It is only an adapation after the achievement of flight - and the extinction of any flightless prespecies - that birds found other niches where their flight withered.

In fact, I'm not sure it makes sense to call the flightless precursors of birds 'birds' at all. They would be ... lizards. I submit that the definition of birds is that it is that precursorial line of lizards that did develop flight.

It takes many thousands to million years for a species with certain characteristics to evolve . How can we begin to speculate what was there before a particular species.

 

[DaveC426913]

It takes many thousands to million years for a species with certain characteristics to evolve . How can we begin to speculate what was there before a particular species.

We can see that all species that followed it had a certain trait. That is powerful evidence that he ancestor had that trait. To wit: flight.

If the precursors to penguins could not fly, they would not have wings. Wings were fully developed as flight controls before penguins went swimming and lost the ability, if not the structures.

Same with legs in whales. And snakes while we're at it.

 

[cosmos 2.0]

We can see that all species that followed it had a certain trait. That is powerful evidence that he ancestor had that trait. To wit: flight.

If the precursors to penguins could not fly, they would not have wings. Wings were fully developed as flight controls before penguins went swimming and lost the ability, if not the structures.

Same with legs in whales. And snakes while we're at it.

M y point is what if precursors to penguin were both aquatic and land based animal/bird. Then we have to go further back in time , which i feel sometimes becomes speculation.

I agree with the idea of using traits.
Problem with evolution is when we go further and further back, its difficult to understand what processes, pressures or traits were involved.

 

[madcat8000]

So we're not apes, we are apoids? How spell semantics?
Watch Dawkins call us apes.
argue with him about it.

and this>>>
http://richarddawkins.net/articles/4121-elaine-morgan-says-we-evolved-from-aquatic-apes

Actually were the third or forth subspecies of chimpanzees, Homo Sapian is a sever misnomer in that we were given our own classification through hubris. Hopefully well have that little mistake corrected in textbooks someday. Technicly we should be Pan sapien.

 

[JordanN]

Edit: Never mind.

 

[DaveC426913]

M y point is what if precursors to penguin were both aquatic and land based animal/bird.

How could proto penguins have developed wings if they never flew?

Then we have to go further back in time , which i feel sometimes becomes speculation.

I agree with the idea of using traits.
Problem with evolution is when we go further and further back, its difficult to understand what processes, pressures or traits that were involved.

If two animals share a trait, then (barring convergent evolution), they acquired that trait prior to speciating.

 

[bobze]

We can see that all species that followed it had a certain trait. That is powerful evidence that he ancestor had that trait. To wit: flight.

If the precursors to penguins could not fly, they would not have wings. Wings were fully developed as flight controls before penguins went swimming and lost the ability, if not the structures.

Same with legs in whales. And snakes while we're at it.

Bingo Dave.

Birds are birds, collectively, because they share a common ancestor who must have flown, The chances that lineages split off while they were "proto-birds", yet evolved all this time the exact same characteristics (wings, feathers, metabolic regulation, musculature, etc) is unrealistic.

 

[cosmos 2.0]

How could proto penguins have developed wings if they never flew?



If two animals share a trait, then (barring convergent evolution), they acquired that trait prior to speciating.

question is are those appendages (penguin flippers ) thought to come from wings that evolved under certain conditions ?

 

[eggomaniac]

Bingo Dave.

Birds are birds, collectively, because they share a common ancestor who must have flown, The chances that lineages split off while they were "proto-birds", yet evolved all this time the exact same characteristics (wings, feathers, metabolic regulation, musculature, etc) is unrealistic.

Dave and Bobze, it goes back to the title question. Which way is the chicken crossing the road?
1. I can contemplate the notion they, and other flightless birds, lost their ability to fly, especially if there are fossils showing this pattern.
2. Is it impossible chickens, and others, are in between, in the process of, becoming full flighted birds? You, yourself, and others claim birds were once reptiles.
It boils down to 2 possibilities, measured in Steps.
A. Step 1, lizards: Step 2, dodos, chickens: Step 3, eagles, hummingbirds
or your choice, if I understand what you are saying >>>
B. Step 1, lizards: Step 2, dodos, chickens: Step 3, eagles, hummingbirds: Step 4, Back to flightless
Instead of penguins, once flew, maybe?, it is one day they will fly!?
[[[ I wonder if the Earth is old enough for Option B
I don't know if there is enough 'proof' to confirm which one.
hmmmmm... Could, did, would any birds go back to being reptiles? eh

 

[turbo]

Something to think about. Here in Maine, we have ruffed grouse. They are strong fliers, at least for short distances, and when I shoot them, I harvest pretty much only the breast meat, because that's where all the muscle is. Their thighs and legs aren't worth dealing with - there is no meat in them. They are not descended from chickens. They are fast and skilled fliers (at least in short bursts in heavily-wooded terrain), but most of their muscle mass is dedicated to providing that adrenaline-pumping burst of speed when they flush. (Upland-game hunters know what I mean). Where do they stand in the evolution and the human selection of desirable traits that led to today's chickens?

 

[NobodySpecial]

No, we are not descended from apes.

I think that article is trying to emphasize that we are not descended from any of the other current great ape species - which is of course correct.

But to the extent that 'ape' has a meaning it is synonymous with the family 'Hominidae' = the great apes. One species of the family of Hominidae, along with our cousins gorilla and chimps, is homo sapien - or if you are feeling particularly pleased with yourself, "homo sapien sapiens"

I'm an ape, my parents were apes, the common ancestor of homo-sap and chimps was an ape and the common ancestor of human-chimp and gorillas was an ape.

 

[eggomaniac]

Eggomaniac, if I might try to help you to grasp what it is, it seems to me, that you are missing: I always think that the whole misunderstanding about the common ancestry of apes, of primates or of whatever other point you want to take in the complex phylogenetic structure has the wind taken out of its sails by this little astonishing evolutionary fact: There is powerful evidence, from microbiology, that human beings have a common ancestor with fruit flies. Now grasp it straight away, that common ancestor was neither fruit fly nor human. It might have borne no obvious morphological resemblance to fruit flies or human beings. And yet, whatever is common between modern fruit flies and modern humans – and there is a great deal more commonality between us than you might realize – existed in that common ancestor. There are any number of vastly different modern species who have a common ancestor, if you go far enough back down the evolutionary chain, but whose common ancestor would not belong to the modern classification of either modern species. So, the obvious morphological similarities between human beings and any other primate species is pretty powerful evidence that our common ancestor is much more recent than is human beings common ancestor with fruit flies. But that common ancestor still existed an awfully long time ago, and there is no accuracy at all in the idea that human beings are descended from any other modern primate.

Hey, if you check the Posts, someone else started the ape/human,,, side track. for the record, I'm just a passenger on that one. Now I wish he had started his OWN Thread.
What makes you think I can't 'fathom' flies as ancestors? In Krauss's talk about the Universe of Nothing he says our earliest 'ancestor' is star dust'. If I can contemplate that, what is so hard about flies, or anything with carbon and protein being our ancestor?
Dawkins calls us the 5th Ape and isn't He sort of the highest and mightiest of this stuff.
[[Reading your comments, sorry for my poor vocabulary, I can't understand if you are saying we are apes or no?]]
If someone started a Thread on that SEPARATE Topic, I would like to see if the Origin of Thought figured in there!? That is the main, pertinent, question in any ape/human study/debate.

 

[Evo]

My comment last night was based on

“Many of the world’s largest flightless birds, known as ratites, were thought to have shared a common flightless ancestor. We followed up on recent uncertainty surrounding this assumption,” said Dr Phillips.

“Our study suggests that the flighted ancestors of ratites appear to have been ground-feeding birds that ran well. So the extinction of the dinosaurs likely lifted predation pressures that had previously selected for flight and its necessary constraint, small size. Lifting of this pressure and more abundant foraging opportunities would then have selected for larger size and consequent loss of flight.”

http://www.sciencealert.com.au/news/20102201-20523.html

Apparently they had earlier ancestors with flight.

 

[eggomaniac]

Now that would make an interesting timeline, size and location species chart.
150 million year ago Archaeopteryx, [first bird] 0.5 m in Germany, leading up to a small flying tinamous of South America, then dinosaurs dieing off 65 million years ago for the develpoment of very large ratites, mostly in NZ and Au. It would seem to put 50 million years as a ball park figure for species change, among birds, anyway.
Edit; add 5 to 10 million years
http://en.wikipedia.org/wiki/Anchiornis

 

[Ken Natton]

Okay eggomaniac, if I misread what it was you didn’t understand then I apologise. But there is no doubt, when you keep talking about which direction penguins are evolving in you are misunderstanding something pretty fundamental. Penguins are not evolving in any direction. No species ever evolves in any direction. You might have a case to argue about what penguins evolved from – although I have to say the evidence that they are descended from flighted birds is quite strong and it does not depend on interpreting their flippers as vestigial wings – but there is unquestionably no case to argue what they are going to evolve into. That depends on parameters we can’t know because they belong to the future. So to put it in terms of your original question, the chicken isn’t crossing the road in either direction. Perhaps it’s walking along the road, and no-one knows where it is headed.

 

[Dr Lots-o'watts]

Here's perhaps another way to phrase the question:

Assuming all birds have a common ancestor, were the ancestors' wings big enough for flight?

Perhaps it was a species where a fraction had wings big enough to fly, and the rest didn't. As such they evolved in different ways.

It could be argued that chickens are a species that were smart enough to get someone else to feed them. They didn't need good wings.

 

[NobodySpecial]

were the ancestors' wings big enough for flight?

The very first ancestor, no, the birds gradually evolved from reptiles and the wings developed from feathers to keep you warm, then enough wings to help you jump, then enough to get into a tree etc. But the last common ancestor of all modern birds was a good flyer.

Perhaps it was a species where a fraction had wings big enough to fly, and the rest didn't.

No, all modern birds have too many adaptations that are purely for flight, beaks to save weight, hollow bones, breastbones, dry waste etc

Modern flightless birds followed a sort of hump, they gradually evolved to fly, then slowly lost that ability when life on the ground seemed a better bet.

 

[Ken Natton]

Perhaps I should make this more explicit. The most powerful evidence of common ancestry of all bird species comes form microbiology and embryology, not from final morphology.

 

[cosmos 2.0]

Perhaps I should make this more explicit. The most powerful evidence of common ancestry of all bird species comes form microbiology and embryology, not from final morphology.

what about genetics ?

Has genetics of both flightless birds and birds that fly been studied ?

 

[Ken Natton]

Yes, okay cosmos 2.0, I didn't mean to leave anyone out. It just seemed to me that people were speculating about common ancestry on the basis of the adult form. I only sought to highlight that it is not the most reliable indictor.

 

[eggomaniac]

Perhaps I should make this more explicit. The most powerful evidence of common ancestry of all bird species comes from microbiology and embryology, not from final morphology.

From the link in Evo's Post, above. # 33.

The study, led by Dr Matthew Phillips, an ARC Postdoctoral Fellow at the ANU Research School of Biology, looked at the mitochondrial genome sequences of the now-extinct giant moa birds of New Zealand. To their surprise, the researchers found that rather than having a flightless relative, their closest relatives are the small flying tinamous of South America.

Their molecular dating study suggests that the ancestors of the African ostrich, Australasian emu plus cassowary, South American rheas and New Zealand moa became flightless independently, in close association with the extinction of the dinosaurs about 65 million years ago.

As a layman, I don't know if mitochondrial sequencing and/or molecular dating is microbiology, embryology and/or morphology.

 

[eggomaniac]

But there is no doubt, when you keep talking about which direction penguins are evolving in you are misunderstanding something pretty fundamental. Penguins are not evolving in any direction. No species ever evolves in any direction. You might have a case to argue about what penguins evolved from but there is unquestionably no case to argue what they are going to evolve into. That depends on parameters we can’t know because they belong to the future. So to put it in terms of your original question, the chicken isn’t crossing the road in either direction. Perhaps it’s walking along the road, and no-one knows where it is headed.

I have been astounded by the courteous and helpful responses.
In layman's terms, are you saying if something isn't broken it does not get fixed? Thanks for opening my eyes to this facet of the discussion. To clarify, it takes forces, such as extinction events and continental shifts to drive a species into adaptation. right?
It is interesting and ironic, to me, to learn from an evolutionist that most animals are probably not evolving. That's a beauty!

I must say, when I first skim read your Post 'not evolving' I shuddered it was going to get into the dreaded creation evolution debate. [Thank God never you never meant NOT not evolving, whoops, thank Darwin I should say?, OR thank Nothing would satisfy Krauss. ]
This is ponderous! Do scientists conclude all animal traits and characteristics derive from major events? I know life has been around for 1/2 billion years?, but only 100's of millions? for larger forms, but there have only been a few major extinctions.
Maybe minor events have an affect as well? Now I have been warned to not propose theories, but to pose my new question, maybe the ice ages, encroaching and receding, developed the migration of monarch butterflies and whooping cranes? Big forest fires, maybe?, caused Pacific salmon to migrate every four years? These are not my 'theories' just a way to pose my question.
Is the ring around a pheasant's neck and all other characteristics and traits attributable to some changing environmental conditions? It seems easy to point to continental shift as the reason there are penguins, but explaining all of the minor details in relation to the historical events would take a book the size of Montreal, eh? Why do Baltimore Orioles have roofs and other birds don't? and a billion other 'examples'.
I guess I 'know' the answer is all of these details are from external forces and it's more a question of verification? It is ponderous, though!
The time line with changes and events, events and changes, rather would be so interesting.

 

[DaveC426913]

I have been astounded by the courteous and helpful responses.
In layman's terms, are you saying if something isn't broken it does not get fixed? Thanks for opening my eyes to this facet of the discussion. To clarify, it takes forces, such as extinction events and continental shifts to drive a species into adaptation. right?
It is interesting and ironic, to me, to learn from an evolutionist that most animals are probably not evolving. That's a beauty!

I can't be sure but I suspect you are being deliberately obtuse.

Ken Natton did not suggest that most animals are not evolving. Everything you said following that is a complete red herring.

What he said was no animals are evolving in any direction (i.e. a specific direction). He said this because it seems that is what you're thinking.

Birds did not "evolve toward flight". All that happened was that small lizards that were able to escape prey, did so, thus passing along their genes. If the lizards' environment had changed even slightly (a spurious example: predators could climb trees and jump on them from above), then the lizards would have not survived any better. The ability to jump far with low mass and some control would never have evolved into flight. Those animals would have been eaten, a different set of lizards (say, ones that could see better at night) would have dominated.

 

[Ken Natton]

Ken Natton did not suggest that most animals are not evolving.

Far from it. It is another key point to grasp eggomaniac. And because I think it might help you to attend to this point, I will tell you that following is a point that I only finally got quite recently, from engagement with people who understood better than me, on another forum.

But before I get to that, let me make one easy assertion to pick up on Dave’s point. It is clear, all species are constantly evolving. They cannot do otherwise. You should understand this: The current human population of planet Earth is what? About 6 billion? And each and every last one of us is a mutant. So is every living instance of the something like half a million different species of beetle that inhabit planet earth. But for those mutations to become something like a noticeable, measurable, evolutionary change requires one vital component: Time. Large quantities of it.

So here’s the point that was such a big ‘ah ha!’ for me. Our closest relative is the chimpanzee, right? But between our common ancestor and modern chimpanzee’s are several other species that no longer inhabit planet Earth but are all ancestors of modern chimpanzees. And between that common ancestor and modern humans are several other, other species that no longer inhabit planet Earth but are all ancestors of modern humans. But nowhere in evolutionary history can you point to a boundary between one species and the next. Oh look! There’s the last of our ancestor species, and there’s the first homo sapiens. It is not meaningful to talk about ‘the first human being’.

 

[madcat8000]

I think that it might be simpler put by saying that chickens are evolveing in every possible direction at all times. One is slightly stronger than another at flying, another running, and another at being a fatter meal for humans. As humans we are the major effect on their environment so the one that is a fatter meal is selected for and the other two who are nuissances are selected aginst. Thus chickens have evolved with our guidence to get fatter. But every individual is a mutant and with proper population numbers and generations new variants will arise. If man were removed from the equation then fast runners and strong flyers will have a chance to prove themselves in the wild. They will continue to radiate(mutate and expand into all possible niches) assumeing they arent killed off quickly. Its just not possible to say how an animal will evolve without knowing the ways in whitch its genome can be changed and what challenges the animal will face as these two things are the essance of evolution.

 

[Dr Lots-o'watts]

The very first ancestor, no, the birds gradually evolved from reptiles and the wings developed from feathers to keep you warm, then enough wings to help you jump, then enough to get into a tree etc. But the last common ancestor of all modern birds was a good flyer.


No, all modern birds have too many adaptations that are purely for flight, beaks to save weight, hollow bones, breastbones, dry waste etc

Modern flightless birds followed a sort of hump, they gradually evolved to fly, then slowly lost that ability when life on the ground seemed a better bet.

Ok, but before wings got big enough for flight, they certainly had to be too small for it (I say "wings", but you can include all other flight adaptations). I don't know which species from the "ancestor that had wings too small". But it's an interesting subject.

 

[bobze]

I have been astounded by the courteous and helpful responses.
In layman's terms, are you saying if something isn't broken it does not get fixed? Thanks for opening my eyes to this facet of the discussion. To clarify, it takes forces, such as extinction events and continental shifts to drive a species into adaptation. right?
It is interesting and ironic, to me, to learn from an evolutionist that most animals are probably not evolving. That's a beauty!

Biological evolution is always happening. It is the change of allele frequencies over generations (that is the fact of evolution). How those changes are happening is explained by natural selection (among others).

I believe you are thinking too big, limiting to only things like "continental shifts". An organisms environment is the sum total of biotic and abiotic factors with which it interacts. This means anything from tiny changes of climate, or mineral availability to new species of gut-flora (bacteria in the GI tract). All of these things, no matter how small, will exert selective pressures on a population.

Now this is the important part--We call different forms of variation, at the gene level, alleles. And different alleles (variation) are slightly more beneficial to surviving and reproducing in an environment (remember, the sum total of biotic and abiotic factors). However slight then, the probability of some variation being passed on will be greater than other variation relative to the environment it inhabits.

Since the probability that some piece of variation's beneficialness to survival is not equally distributed, then individuals in a population will not have an equally likely chance to survive and reproduce.

The consequence of this is that from generation to generation the allele frequency of a population will change, with respect to which piece of variation was the most beneficial in the current environment.

We call this (drum roll please), natural selection--Because no conscious choice is being made which pieces of variation is passed on.

This is opposed to artificial selection types, where conscious choice (not the impact on survivability in an environment) is responsible for which variation makes it into the next generation. For example, humans choose the meatiest, most succulent chickens to breed and put their genes (their specific variations) into the next generation. Or, bees choose which flowers are most appealing to them, thus they choose which plants will get their genes in the next generation.

I must say, when I first skim read your Post 'not evolving' I shuddered it was going to get into the dreaded creation evolution debate. [Thank God never you never meant NOT not evolving, whoops, thank Darwin I should say?, OR thank Nothing would satisfy Krauss. ]
This is ponderous! Do scientists conclude all animal traits and characteristics derive from major events? I know life has been around for 1/2 billion years?, but only 100's of millions? for larger forms, but there have only been a few major extinctions.

No! "Characteristics" do not derive from evolution itself. They derive from the mutability of the genome. In plain words, from the fact that biological replication is not a perfect process, its prone to errors which introduce variation for evolution (by selection) to act upon. If biological replication were perfectly conserved from generation to generation then life on Earth would be pretty boring to behold.

Maybe minor events have an affect as well? Now I have been warned to not propose theories, but to pose my new question, maybe the ice ages, encroaching and receding, developed the migration of monarch butterflies and whooping cranes? Big forest fires, maybe?, caused Pacific salmon to migrate every four years? These are not my 'theories' just a way to pose my question.
Is the ring around a pheasant's neck and all other characteristics and traits attributable to some changing environmental conditions? It seems easy to point to continental shift as the reason there are penguins, but explaining all of the minor details in relation to the historical events would take a book the size of Montreal, eh? Why do Baltimore Orioles have roofs and other birds don't? and a billion other 'examples'.
I guess I 'know' the answer is all of these details are from external forces and it's more a question of verification? It is ponderous, though!
The time line with changes and events, events and changes, rather would be so interesting.

There are, as I alluded to above, other types of selection. Another example, is a special type we call "sexual-selection" where a mate (usually the female) is the one choosing which variation gets passed on. If you're interested I'd check out this webpage hosted by the good folks at Berkeley called http://evolution.berkeley.edu/evosite/evo101/index.shtml" . Its a pretty good layman's primer on evolution and a great starting point. If along your way you have specific questions, I'd be happy to help, but the trying to catch up on everything we know about evolution is probably not time-possible for people on form (especially when they should be studying microanatomy! )

 

[bobze]

Far from it. It is another key point to grasp eggomaniac. And because I think it might help you to attend to this point, I will tell you that following is a point that I only finally got quite recently, from engagement with people who understood better than me, on another forum.

But before I get to that, let me make one easy assertion to pick up on Dave’s point. It is clear, all species are constantly evolving. They cannot do otherwise. You should understand this: The current human population of planet Earth is what? About 6 billion? And each and every last one of us is a mutant. So is every living instance of the something like half a million different species of beetle that inhabit planet earth. But for those mutations to become something like a noticeable, measurable, evolutionary change requires one vital component: Time. Large quantities of it.

That seems to be a pretty common misconception that people have of evolution. By and far, selection is capable of producing measurable change much, much faster than we actually observe.

Even so, it still produces measurable change over very short periods of time. For example, http://www.pbs.org/wgbh/evolution/library/01/6/l_016_01.html" (I think you'll find this most interesting Ken).

So here’s the point that was such a big ‘ah ha!’ for me. Our closest relative is the chimpanzee, right? But between our common ancestor and modern chimpanzee’s are several other species that no longer inhabit planet Earth but are all ancestors of modern chimpanzees. And between that common ancestor and modern humans are several other, other species that no longer inhabit planet Earth but are all ancestors of modern humans. But nowhere in evolutionary history can you point to a boundary between one species and the next. Oh look! There’s the last of our ancestor species, and there’s the first homo sapiens. It is not meaningful to talk about ‘the first human being’.

Yes that is an important concept, its only because the extinction of forms that we can say "you belong to species X and you belong to species Y". If populations didn't die out over time, then the biota of Earth would like one big variable population.

To summarize Richard Dawkin's thought experiment;

Suppose we have a time machine and were off to collect historic ancestors in a manner rivaling the Victorian rape of the natural world.

Suppose we dial up our time machine to 10,000 years ago, leap through the space-time continuum and land in the early swing and bustle of the Holocene.

We grab a male and female ancestor and bring them back to the future, where in a bizarre parody of captive breeding programs we have those ancestors mate with modern humans.

[PLAIN]http://blog.pennlive.com/talkingmovies/2008/03/medium_10000bc.jpg

Now, we repeat our foray into history grabbing ancestors every 10,000 years or so and bringing them back to the future. There comes a point in time, when modern people can no longer interbreed with those we have pirated from the past. Let's dub this ancestor, ancestor X. But, it necessarily follows from descent that one of those ancestors we grabbed can interbreed with ancestor X, the ancestor well call P.

If ancestor P were to then take over our experiment, leap-frogging back in time every 10,000 years from their present day they too would find their own distinct ancestor X.

Consider then, the implications of this for the idea of species. At what finite time, do we define a species? At ancestor X? If that is true, then ancestor P (of our species) would be of a different species then our ancestor X. Yet when viewed from ancestor P's time line, ancestor X would necessarily have to be included in the same species.

Crazy, no?

 

[DaveC426913]

Ok, but before wings got big enough for flight, they certainly had to be too small for it (I say "wings", but you can include all other flight adaptations). I don't know which species from the "ancestor that had wings too small". But it's an interesting subject.

This is something I alluded to previously that is critical to the correct understanding of evolution: wings and feathers that were too small to achieve flight did not evolve toward the purpose of flight. Wings and feathers evolved out of some other, unrelated drivers (such as mating plumage or winter downy coating). They served this purpose well, and it was only a side-effect that, when their environment changed, these winglike, featherlike things had an unexpected use in helping with gliding.

That is how wings-that-are-too-small-to-fly evolved into wings-that-are-big-enough-to-fly.

 

[Dr Lots-o'watts]

This is something I alluded to previously that is critical to the correct understanding of evolution: wings and feathers that were too small to achieve flight did not evolve toward the purpose of flight. Wings and feathers evolved out of some other, unrelated drivers (such as mating plumage or winter downy coating). They served this purpose well, and it was only a side-effect that, when their environment changed, these winglike, featherlike things had an unexpected use in helping with gliding.

That is how wings-that-are-too-small-to-fly evolved into wings-that-are-big-enough-to-fly.

I agree with this. So in the absence of any other evidence (as a non-biologist, I'm not very aware of the archeological evidence collections out there), I can not be convinced that a chicken descends from a flying creature. Looking at a chicken alone, it could still be on its way from a non-flying creature, towards a flying one. It's on stand-by.

By continuously breeding the top percentile that manages to stay in the air the longest (by jumping and gliding) when I scare them, in millions of years, we'd get flying "chickens".

Heck, even by breeding mammals this way, I don't see why we wouldn't get there.