Macro-evolution (speciation)?

[voyd]

Micro-evolution occurs within species and is generally-accepted by both scientists and Creationists.

The current point of debate though is "macro-evolution," or where one species can evolve into another (speciation).

Macroevolution refers to large-scale changes in gene-frequencies in a population over a long period of time, and is usually taken to refer to events that result in speciation, the evolution of a new species. While microevolution has been demonstrated in the laboratory to the satisfaction of most observers, macroevolution has to be inferred from the fossil record, the traits of extant organisms, and comparisons of molecular evidence (DNA). Its precise mechanisms are an active topic of discussion amongst scientists.

So, what exactly is a species?

Loosely speaking, a species is a related group of organisms that share a more or less distinctive form and are capable of interbreeding

However,

Since it assumes sexual reproduction, it leaves the term undefined for a large class of organisms that reproduce asexually.

Hence,

no species concept yet proposed is entirely objective, or can be applied in all cases without resorting to judgement

So, the definition is somewhat broad, but a generalization in sexually-reproductive species is that they have compatible chromosomes that allow breeding.

For example, humans have 46 (diploid) chromosomes and other primates (orangutan, gorilla and chimpanzee) 48. Hence, we are different species and (assumedly) can't breed. Although, that last assumption is more a fuzzy than a hard line. For example:

The last remaining species of wild horse, Przewalski's (sha-val-skis) Wild Horse has 66 chromosomes while the domesticated horse has 64 chromosomes. Despite this difference in chromosome number, Przewalski's Wild Horse and the domesticated horse can be crossed and do produce fertile offspring

Anyways, I suppose intra-species diversity enhances survival chances up to a certain amount - but after that could actually work against it. Imagine if an owl and a fish could interbreed? Chances are its hybrid offspring wouldn't have a chance in h*ll of surviving. So, nature seems to "allow" an optimum amount of beneficial biodiversity before it segregates them reproductively. Hence, it appears that greater genetic diversity decreases fertility in a balanced trade-off.

Anyways, the question is - how and when exactly would species genetically diverge enough to become a new one - and not be able to even breed with its own ancestors? Does anyone know of good fossil or genetic evidence for this?

This is claimed to be one example? Is it valid, and know of any others?

One famous example is Hawaiian flies. Many of the small islands have endemic fly species. Theoretically, flies migrated to the smaller islands when the islands had recently emerged by volcanic action. Separated from the main population, the small fly population diverges genetically, adapting to the new island until it is a separate species from the original parent population.

[space virgin]

There was an article recently about ducks and dinosaurs. My nerd capabilities lay more in the physics / astronomy / chemistry realm, I ain't no biologist. I remember some interesting theories about birds being possibly related to horses way, way, way back.

There are so many theories about what "should" work and what "shouldn't" work, and yet so many times something happens that "shouldn't" or something doesn't happens that "should", according to science. I think we're going to be facing a lot of really interesting and theoretically "impossible" discoveries during our lifetimes.

[omisan]

Damn, if you asked this years ago when I was an anthro major and actually keeping up with the stuff, I probably would have been able to find you some solid answers. But since my days in academia are well behind me, all I can say is:

[Rozza]

there are a few physisits working with biologist to come up with a theory that all life will come to the same conclusions, for example human eyes and octopus eyes, there has been no relation between the two species for millions of years, but yet evoulution has come to the same conclusion

[Rozza]

Anyways, the question is - how and when exactly would species genetically diverge enough to become a new one - and not be able to even breed with its own ancestors? Does anyone know of good fossil or genetic evidence for this?

i suppose it could be a kind of 'anti-half-life' if you like. with half life, of a radioactive supstance as you know it halfs each time, so then the time halfs by the half and so on and so forth.

well take an ambia, one cell, organelles. you have an animal

then during mitosis, the cell dosent seperate, you then have a different animal, a primitive jelly.

and the other ambias cannot consume it,

this continues until cells become specialised, you then begin to develop tissue, organs, then structure to support the organs. but to get to the next stage it takes alot more than a small group of cells staying together

just a thought

[butterj]

damn intresting stuff, brain food.

[Phinehas]

I would have to say that from the other end of the spectrum that there has really never been where a species diverges so much that it is a whole new animal i mean yes there is micro evolution that is proven and even to the fact that a new species of fly can come from an older one but never in history or in studies has it been proven that a bird came from a fish or vice versa but thats me as a creationist and I believe that :

And God said, Let the waters bring forth abundantly the moving creature that hath life, and fowl that may fly above the earth in the open firmament of heaven. 21 And God created great whales, and every living creature that moveth, which the waters brought forth abundantly, after their kind, and every winged fowl after his kind: and God saw that it was good. 22 And God blessed them, saying, Be fruitful, and multiply, and fill the waters in the seas, and let fowl multiply in the earth. 23 And the evening and the morning were the fifth day. 24 And God said, Let the earth bring forth the living creature after his kind, cattle, and creeping thing, and beast of the earth after his kind: and it was so. 25 And God made the beast of the earth after his kind, and cattle after their kind, and every thing that creepeth upon the earth after his kind: and God saw that it was good. 26 And God said, Let us make man in our image, after our likeness: and let them have dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth.

but this is me, and actually i know quite a few secular scientists that are saying that theory of evolution should not be taught as fact in schools cause alot of contriversy has come about lately about this. Anyways I say that it has never been proven one way or the other so both thoughts take faith to except.

[Sijuki]

As far as bugs and what not I haven't seen much. Although along the lines of human beings I did just recently watch an episode that talked a bit about the previous stages of man. Neanderthals, homo erectus, etc. It was the first show I had seen that finally had scientists talking about interbreeding amongst the species because modern man has characteristics from several of the previous species. Also the last ancestor of man died out some many years after modern man came around so they are beginning to believe that we just merely bred and killed them off. It is something I would like to look more in depth into, so perhaps I will and report back with what I find.

As far as being closely related to chimps, has anyone ever tried to reproduce with a chimp? I am sure there is some crazy scientists that has. Wonder if it could work?

[TheJake]

I havent tried sij... I swear!

[kingcrazylegs]

Can I buy a vowel?

Guess I am just not scientificly minded.

[joanofarc]

I LOVE YOU.

[LiveFreeorDie]

This is actually an interesting thread that I missed somehow last year. Thanks to Joan's un-requited lust, I mean love, we can re-visit it.

So, here is an interesting example to me that is sort of related and pertains to snakes:

Take Pythons and Boas. Two different species. Pythons are from Africa/Asia. Boas are from the Americas. Pythons lay eggs. Boas give birth to live babies.

There is a python called the Green Tree Python. There is a Boa called the Emerald Tree Boa. They are nearly identical in appearance right down to a very distinctive way in which they wrap themselves around a branch. You can see them on this page:Snakes

So, to Voyd's point, what is it that led to A.) One group of snakes evolving in such a way as to give birth to live babies versus eggs and B.) Two separate species of snake that live on different continents but are nearly identical in appearance and habits, etc....parallel evolution??....were they the same at one point and then diverged...but what about the egg laying versus live birth?? hmmm????

Voyd - did you ever get an answer to your question?

[joanofarc]

unrequited? gee... that's kind of harsh! i'd like to think it's only half-requited, that's there's a chance out there somewhere waiting for me ~ thank you very much! hehe

[Rozza]

Originally posted by joanofarc@Nov 16 2005, 11:39 PM
unrequited?* gee... that's kind of harsh!* i'd like to think it's only half-requited, that's there's a chance out there somewhere waiting for me ~ thank you very much!* hehe*

[snapback]87737[/snapback]

a pistol and some viagra?

[joanofarc]

bastard... maybe some handcuffs and a bottle of rum!

[Rozza]

Originally posted by joanofarc@Nov 16 2005, 11:52 PM
bastard...* maybe some handcuffs and a bottle of rum!

[snapback]87741[/snapback]

you drink the rum, then either a) spike voyds drink, and handcuff him

or

B) skip the foreplay and hit him over the head with the bottle and handcuff him

<- haha gimp mask!

[joanofarc]

gimp mask! oh yeah!? i'm sure i could find some kind of use for you in this whole scenario MUAHAHHAHA

[Rozza]

Originally posted by joanofarc@Nov 17 2005, 12:21 AM
gimp mask!* oh yeah!?* i'm sure i could find some kind of use for you in this whole scenario* MUAHAHHAHA

[snapback]87748[/snapback]

"Release the Gimp"
"he's asleep"
"then Wake him up"

[Killer Cyborg]

The theory of evolutionary convergence has not been discussed