For those wondering what "macroevolution" actually is...

[Frank Robert]

Those genetic barriers are a jolly nuisance, aren't they?

You are assuming that macroevolution has a single path. Natural selection doesn't choose the path of evolution and Genetic barriers can further promote speciation by creating pre- or postzygotic barriers to reproduction.

 

[FrumiousBandersnatch]

By "macroevolution" I mean one Class of organisms evolving into a different Class of organisms.

OK. I agree, that doesn't happen - and evolutionary theory says it doesn't happen. Birds won't become mammals and mammals won't become crustaceans... classes are separate branches of the evolutionary tree.

I'd like to think Evolution 101 can help you with this.

 

[pgp_protector]

I want a guard dog as big as a horse, but those useless dog breeders can't build me one. Guess I'll have to get an evolutionary scientist to fill that order.

 

[Gene2memE]

I can't think of any reason why natural selection would be any more conducive to macroevolution than artificial selection

I can. Phase space.

Since artificial selection encounters genetic barriers, so will natural selection.

What are these 'genetic barriers'? Can you name some?

 

[Buzzard3]

Not really, they highlight evolution perfectly. Tigers and lions are still big cats, belonging to the Felindae family, but they can't create viable, fertile offspring. We'd expect to see that in evolution.

Why would we expect to see that?

 

[Buzzard3]

I can. Phase space.

Ah yes ... we learnt all about that in Grade 2, but I forget it. Can you remind me please?

What are these 'genetic barriers'? Can you name some?

No dog breeder can produce a pink dog or one as big as a horse. No chook breeder can produce a chook as big as a turkey. No human is ever going to run 100 metres in one second.
Genetic limitations exist ... even Blind Freddy can see that.

 

[SelfSim]

Ah yes ... we learnt all about that in Grade 2, but I forget it.

Grade 2???

 

[Shemjaza]

Why would we expect to see that?

Because they are different, and in the many thousands of years that the two populations have been isolated from each other the differences have compounded.

 

[Gene2memE]

Ah yes ... we learnt all about that in Grade 2, but I forget it. Can you remind me please?

The available space of potentially evolutionary successful mutations. In artificial selection, it's massively limited compared to that of natural selection. And, potentially useful mutations may be eliminated because they carry with them traits that the artificial selector doesn't want.

No dog breeder can produce a pink dog

I disagree.

'Pink' dogs - those with a rare type of albanism - already exist (they're white with a pinkish tinge). It would not be that difficult to use cross breeding to amplify this and produce a pink dog.

Looking up the story of the black tulip would be illuminating here. It was considered impossible to produce a true, solid black tulip. It took around 350 years, but Dutch tulip breeders eventually produced a true black tulip (by crossing two types of purple tulip, themselves artificially selected).

or one as big as a horse.

Given that modern horses descended from a creature around the size of a labrador, I disagree. Also, given that modern small horse breeds and modern large dog breeds are roughly similar in size, I emphasise my disagreement.

No chook breeder can produce a chook as big as a turkey.

Modern domesticated chicken and turkey breeds are multiple times larger and heavier than their wild ancestors. A wild turkey usually maxes out at about 20-25 pounds in a male. A domesticated turkey maxes out at about 85-90 pounds. That's an increase of about 300% to 400%.

If you're going to breed for gigantism and nothing else, it may actually be possible to produce a chicken that's bigger than a turkey. Bear in mind that the ancestor of the chicken weighs a bare three to four pounds, and modern commercial hens weigh about eight to ten pounds.

How Did Modern Chickens Get So Damn Big?

Per the article above, the average weight of a US commercial hen has increased from 905 grams in 1957 to 4202 grams in 2005. That's an increase of 365% in under 50 years.

Perhaps you should look up the history of the domestication and cultivation of brassica, and the particularly gnarly genetic path their hybridisation and domestication took.

 

[Warden_of_the_Storm]

Why would we expect to see that?

Because they're different species.

 

[Buzzard3]

So, the variation of humans, whales, apes, rats, kangaroos and platypuses is all micro evolution because they are still in the class mammalia?

In that case I will have to review my decision.

 

[Shemjaza]

In that case I will have to review my decision.

If it makes you feel better you can just acquire AV's method of calling Genus an analogy for the "Created Kinds" on Noah's Ark.

With miraculous plagues as an add of to explain the variation of the Genus Homo.

 

[Larniavc]

By "macroevolution" I mean one Class of organisms evolving into a different Class of organisms.

That’s not evolution. Whoever told you that was lying.

 

[AV1611VET]

If it makes you feel better you can just acquire AV's method of calling Genus an analogy for the "Created Kinds" on Noah's Ark.

This helps too:

Etymology of "Genus"

genus: 1550s as a term of logic, "kind or class of things" (biological sense dates from c. 1600), from Latin genus (genitive generis) "race, stock, kind; family, birth, descent, origin"

 

[Shemjaza]

This helps too:

Etymology of "Genus"

genus: 1550s as a term of logic, "kind or class of things" (biological sense dates from c. 1600), from Latin genus (genitive generis) "race, stock, kind; family, birth, descent, origin"

Which would also leave it just as synonymous with other terms used for long scale descent in evolutionary science.

 

[AV1611VET]

Which would also leave it just as synonymous with other terms used for long scale descent in evolutionary science.

Which term came first? "kind" or "genus"?

I say "kind" came first, until the tares got into the Bible and changed it to "genus".

Which term came first? "child in the womb" or "fetus"?

I say "child in the womb" came first, until the tares got into the Bible and changed it to "fetus".

Which term came first ...

 

[ottawak]

Which term came first? "kind" or "genus"?

"Genus" is Latin and so predates the English word "kind."

Which term came first? "child in the womb" or "fetus"?

Again, "fetus" is Latin and so predates the English phrase.

 

[Warden_of_the_Storm]

"Genus" is Latin and so predates the English word "kind."



Again, "fetus" is Latin and so predates the English phrase.

AV believes that Jacobean English predates Latin, as it was the language used across the world before the Tower of Bable and was 'rediscovered' for writing the King James bible.

He doesn't care.

 

[AV1611VET]

He doesn't care.

About what?

 

[Warden_of_the_Storm]

About what?

Can't tell from context?