Evolution

[RidgeHunter]

Somewhere along this road we (at least those of us who aren't deluded) know that human brain size doubled over what is contextually a very short time period. Who's we? We is them and I. How do I know this? I know this because many, many people smarter than me (them) figured this out, and listening to smart people when you're not smart is better than listening to dumb people.

Anyways, what we don't know exactly is why our brains doubled in size. Food security coupled with tool use and language development but hey language came first right anyways we don't really know. Hey cool moon rockets and cell phones and language and fake plastic tits yay cool awesome big brains fawking rule.

A saltwater crocodile has a brain approximately the size of a walnut. It's highly complex, for being the size of a walnut, but a good majority of it is focused on eating. Anyone want to guess how long those guys have been around? That's perfection.

Us? We're an evolutionary mistake. We're an exotic supercar. Sure it's cool when it blows by you in the passing lane, but that old FJ60 Toyota puttering along with the tractor engine in the right lane is undoubtedly a more perfect vehicle. See of you can get the odometer on a Ferrari and a Toyota to match under the same conditions with the same amount of maintenance and breakdowns.

 

[Eagle Eye]

which creates a new genus which is considered a form of speciation....which is evolution. is it not? hybridization is mutation

depends on what species concept you accept. There are a few species concepts, here are two examples, biological species and phylogenetic species.
Evolution does not happen to individuals, but populations. If we have a barn full of donkeys and horses (two species living in one area), and after one mating season, there are now donkeys, horses, and mules, we would conclude that micro evolution had occurred, and some people would say macro evolution occurred.
however, some would not say its macro evolution! Since donkeys and horses can breed and produce offspring, therefore horses and donkeys are not different species. Now, most mules are sterile, which would strengthen the argument that horses and donkeys ARE different species. BUT, some mules are not sterile (according to the interwebs).
Thus, the answer in regard to macroevolution.... depends on how you define species.

 

[Coded-Dude]

that is why I asked if macro and micro were defined. scientists have recently mapped the genome of quite a few of darwin's finches and found that interbreeding(hybridization) plays a large role in determining the genetic mutations(beak size, etc). while mules are mostly sterile, there are certainly other species for which interbreeding produces partially fertile(sometimes even completely fertile) offspring.

 

[Eagle Eye]

I defined micro and macro evolution in an earlier post, don't blame ya for not reading all this.
The beautiful thing about science is that it is self correcting. In regard to evolution, there is 0 scientific evidence against it. However, some things are still debated, like the definition of a species.

 

[TedKennedy]

there are certainly other species for which interbreeding produces partially fertile(sometimes even completely fertile) offspring.

That's very interesting.

 

[frankos72]

so then what is the difference in micro and macro evolution(has it been defined here yet)? Isn't a mule a form of macro evolution?

Micro evolution are small changes that create a new species our sub species. Like a moth or flower changing color. It has been observed and recorded by modern scientist. It can be seen in certain fossil records where a fossil is found but has one subtle difference from others of its kind.


Macro evolution means a greater leap at once. Like gills turning into lungs. Front legs into arms or wings. Etc. There are huge unexplainable gaps in fossil records (from the micro evolution perspective) that indicate that either micro evolution happens or a creator made totally different kinds of animals in the first place(as the Bible puts it by chance).

Add I read it, this article from Berkley insists that micro evolution occurs through micro evolution. They say we must just assume it happened that way even though there are holes in the records. http://evolution.berkeley.edu/evolibrary/article/evo_48

 

[Coded-Dude]

That's very interesting.

There are countless cases of distinct species which can, in unusual or limited circumstances, form hybrids. One example is the West European carrion crow (Corvus corone) and the Asian hooded crow (Corvus cornix), which have distinct ranges meeting in a narrow "hybrid zone". Another are the Platte river species of sucker fish of the Catostomus genus which live together and only rarely interbreed (Futuyma 1998, p. 454).

One of the most striking instances of partial or incomplete speciation are the numerous "ring species" (for review see Irwin et al. 2001). Ring species, such as the salamander Ensatina, form a chain of interbreeding populations which loop around some geographical feature; where the populations meet on the other side, they behave as completely different species. In the case of Ensatina, the subspecies form a ring around the Central Valley of California—the subspecies freely interbreed and hybridize on the east, west, and north sides of the valley, but where they coexist on the south side they are incapable of hybridizing and act as separate species (Moritz et al. 1982; Futuyma 1998, pp. 455-456).

Another example of a ring species is the gull genus Larus. L. argentatus and L. fuscus were originally identified as distinct species in England. However, there is a continuous ring of Larus hybrids extending to the east and west all the way round the North Pole. Only in England are they incapable of interbreeding.

The Great Tit, Parus major, similarly forms a ring species around the mountains of Central Asia, freely interbreeding everywhere except in Northern China (Smith 1993, pp. 227-230).

Many species can hybridize, but the resulting offspring have reduced fertility. One example is the English shrew (genus Sorex) whose hybrids are reproductively disadvantaged due to chromosomal differences. This has also been seen in lab experiments mating Utah and California strains of Drosophila pseudoobscura. Another example are the frogs Bombina bombina and Bombina variegata, whose hybrids have low fitness (i.e. they do not reproduce very successfully) (Barton and Gale 1993).

Many other species can mate and produce viable hybrids, but the hybrids are infertile. This has been observed in species of amphibians (like certain frog species of the Rana genus) and mammals like Equus (where matings of horse and ass result in a sterile mule). Another example is the newt Triturus cristatus and T. marmoratus, in which hybrid infertility is due to unpaired chromosomes (Smith 1993, pp. 253, 264).

Other species are able to mate with successful fertilization, but mortality occurs in embryogenesis. Such is the case with the frog species Rana pipiens and R. sylvatica (Futuyma 1998, p. 460). This phenomenon has also been observed in Drosophila. Additional examples are also found in plants such as the cotton species Gossypium hirsutum and G. barbadense (Smith 1993; Futuyma 1998, ch. 15 and 16).

http://www.talkorigins.org/faqs/comdesc/section5.html

 

[Eagle Eye]

while mules are mostly sterile, there are certainly other species for which interbreeding produces partially fertile(sometimes even completely fertile) offspring.

Very interesting indeed. Some would consider two "species" that CAN interbreed but NEVER have the potential (due to geographical isolation or temporal isolation) to interbreed as two different species. Some scientists wouldn't, and some that did, might change their mind in light of new evidence.

 

[TerryMiller]

which creates a new genus which is considered a form of speciation....which is evolution. is it not? hybridization is mutation

Not sure, but I seem to remember that mules can't produce offspring.

 

[Coded-Dude]

Not sure, but I seem to remember that mules can't produce offspring.

yes for the most part that is correct, they are not a fertile offspring, but as posted above there are instances of different species which can have fertile offspring.
which brings up another interesting point. when and why mother nature decides to allow/not allow certain species(mutated genomes through hybridization) to survive and procreate themselves.