Do You Believe Darwin's Theory of Evolution? - Page 3 - Video Games Forum

zteccc · #21 (**permalink**) 10-18-2005, 06:35 PM

To answer the thread's question, no I don't belive in the evolution of species from a common ancestor. I also don't believe in abiogenesis (the spontaneous generation of life from lifeless matter).

Are some of Darwin's ideas good and worth consideration, yes, absolutely. For example, Darwin's idea of adaptive changes are quite reasonable within a species. There is, however, no evidence that such adaptive changes will result in a new species. Darwin's finches, as seen in the Galapagos islands, are a good example. Many variations of finches exist on those islands, each with adaptations that make sense for the variation. That said, however, they are all finches. They can all interbreed (although they generally don't) and they can breed with other finches throughout the world. They have not become something other than finches (e.g. they haven't become crows or doves or even snakes). The chromosomes of finches allow for the variations because they are within the variation range of a finch, but they don't gain adapations that are not within the normal variation range for a finch.

As to organized relgion, there are some reasons to avoid them and yet there are some to join them. An organized religion, although flawed (as all human endeavours are) can do more good for the world than a neighborhood gathering. The organization can leverage the size and financial contributions of multiple congregations to provide for disaster relief, medical support, etc. An organized religion gives one a greater pool of associates with similar beliefs which can lead to better, more mutually beneficial friendships and support structures. Also, being a member of such a religion may allow one to bring about change in that religion if it goes astray (much harder to do from the outside). Organized religion is going to be flawed. It is going to be less than the ideal, but there can be positives as well. One should simply choose one that remains as close as possible to the core beliefs of one's faith.

-- Jeff

Diablo · #22 (**permalink**) 10-18-2005, 07:24 PM

Jeff, you are incorrect in thinking that they are all within the same species. Of the 14 finches, they are all a different species, and they span 6 different genuses.

GROUND FINCHES
Small Ground Finch: Geospiza fuliginosa
Medium Ground Finch: Geospiza fortis
Large Ground Finch: Geospiza magnirostris
Sharp-beaked Ground Finch: Geospiza difficilis
Cactus Ground Finch: Geospiza scandens
Large Cactus Ground Finch: Geospiza conirostris

TREE FINCHES
Small Tree Finch: Camarhynchus parvulus
Medium Tree Finch: Camarhynchus pauper
Large Tree Finch: Camarhynchus psittacula
Woodpecker Finch: Cactospiza pallidus
Mangrove Finch: Cactospiza heliobates
Vegetarian Finch: Platyspiza crassirostris

Warbler Finch: Certhidea olivacea
Cocos Island Finch: Pinaroloxias inornata

zteccc · #23 (**permalink**) 10-19-2005, 02:40 PM

Quote:

Originally Posted by Diablo

Jeff, you are incorrect in thinking that they are all within the same species. Of the 14 finches, they are all a different species, and they span 6 different genuses.

There are (and have been) many definitions of species and I'm not a taxonomist, so I'll accept that the are not the same species according to the current taxonomic definitions. That said, my point, that they are all still finches, still stands. They are not crows or doves or anything else.

In one, long standing, definition of species (the biological definition), it is stated that a species is any group of individuals that do not successfully interbreed with other groups. All "dogs" (of the genus Canus) can successfully interbreed (although they don't choose to), therefore one could say that based on this definition that all dogs are in the same species. Similarly, all of the finches (reportedly) can (and do) indeed successfully interbreed. As such, at least by this definition (by biology), they may be considered the same species.

One of the problems is that species can mean so many things. The taxonomist would tell you that the fourteen "species" of finches are different, yet at the chromosome layer, they are completely compatible and thus biologically, they can be considered the same, just expressing variation. Of course some scientists wouldn't agree with this (because it hurts their arguments, especially related to evolution), and yet by definition, most do admit this. So is species a taxonomic issue or a biological one? I tend to lead towards the biological as the true determinant (because that is what evolution is all about, isn't it?).

-- Jeff

Diablo · #24 (**permalink**) 10-19-2005, 05:37 PM

I've been taught, and always thought, that a species is a group of individuals that do not successfully interbreed with other groups in nature, not in captivity or anything along those lines. If that is what you meant, then think about this: do you think that every kind of dog can physically breed with every other dog? Pick some very small breed, and a very large breed, and think about whether or not it is physically possible for them to interbreed naturally. Sure, the genetics may be there, but is it physically possible? For some combinations, it isn't.

Also, do the finches interbreed naturally? If they do, then I agree with you, but I've always thought that they do not interbreed naturally.

zteccc · #25 (**permalink**) 10-19-2005, 06:32 PM

Quote:

Originally Posted by Diablo

I've been taught, and always thought, that a species is a group of individuals that do not successfully interbreed with other groups in nature, not in captivity or anything along those lines. If that is what you meant, then think about this: do you think that every kind of dog can physically breed with every other dog? Pick some very small breed, and a very large breed, and think about whether or not it is physically possible for them to interbreed naturally. Sure, the genetics may be there, but is it physically possible? For some combinations, it isn't.

Also, do the finches interbreed naturally? If they do, then I agree with you, but I've always thought that they do not interbreed naturally.

The problem with adding "in nature" to the mix is that some animals separated geographically may have compatible chromosomes and be therefore biologically the same species, but the don't interbreed simply because they cannot reach each other. The biological argument deals not with physical limitations, but with the chromosomes which is the true test of species (if the chromosomes are the same, then they are the same species). Consider that very few Kalahari Desert people naturally interbreed with New York socialites (probably none), but their genes are compatible and are considered the same species despite many very obviuos physical (adaptive) differences.

It is true that a Great Dane male and a Chihuahua female cannot physically interbreed due to the obvious size problems, but a Great Dane female can interbreed with a Chihuahua male, or for that matter, a Great Dane male can interbreed with a Mastiff who can then breed with a German Shepherd, etc.

As to the finches, yes, they do interbreed naturally. Here's a page to read, but speicifcally the last paragraphs are important (emphasis on the last sentence is mine):

Quote:

Moreover, the Grants' observations undermine another myth about Darwin's finches - that individual species are 'confined to certain islands'. In order for different species to mate, they clearly have to occupy the same territory. Other visitors to the Galapagos have confirmed that this is this case. Television documentary filmmaker Gillian Brown spent a year working at the Darwin Research Station on the islands. It is common, says Brown, to find the different species all over the archipelago, rather than obeying the colored territorial maps drawn up by Darwinist ornithologists.

In almost all respects, the finches of the Galapagos are so similar that it is difficult to tell them apart. Indeed, Weiner himself remarks that, 'Some of them look so much alike that during the mating season they find it hard to tell themselves apart.' This mirrors David Lack's observation that 'In no other birds are the differences between species so ill-defined.' The finches all have dull plumage, which varies from light brown to dark brown, all have short tails, all build nests with roofs, and lay white eggs spotted with pink, four to a clutch.

It is very difficult for an objective observer to see how a group of finches who 'find it hard to tell themselves apart', and who do in fact interbreed, can legitimately be called different species.

-- Jeff

Shane · #26 (**permalink**) 10-19-2005, 07:06 PM

I unfortunately am not well educated enough on the interbreeding of animals to comment Jeff, nor do I feel like reading bias reports (both ways). So I guess I'll have to bow out.

zteccc · #27 (**permalink**) 10-20-2005, 11:39 AM

Quote:

Originally Posted by Shane

I unfortunately am not well educated enough on the interbreeding of animals to comment Jeff, nor do I feel like reading bias reports (both ways). So I guess I'll have to bow out.

You don't need to bow out, just search google for darwin finches interbreed. Here are some sites that may meet your "unbiased" criteria:
http://www.doc.ic.ac.uk/~kpt/terraqu...n/finches.html

Quote:

Similar adaptations eventually led to the 13 species now counted as Galápagos finches (though Steadman points out that even this taxonomic partition is tentative, as several of these finch species can interbreed.)

http://www.talkorigins.org/faqs/wells/finches.html

Quote:

He then says, "Peter Grant acknowledged that if species were strictly defined by inability to interbreed then 'we would recognize only two species of Darwin's finch on Daphne', instead of the usual four" (p. 170).

http://www.carlzimmer.com/articles/2...002_Finch.html

Quote:

The two species on Daphne Major can and sometimes do interbreed, and their hybrids--far from being mulelike reproductive dead ends--are a source of fresh genetic variability.

http://www.pbs.org/safarchive/5_cool...2_asklynn.html

Quote:

Question We have been studying natural selection and how it has led to the development of several subspecies of finches on each island. Do the birds remain on their respective island or do they island hop? If so, can they interbreed with the other finches? (Kenneth Horvath, Middle School Teacher)
Answer Finches sometimes travel between islands when the islands are very close together - they are not strong fliers however, and don't go long distances. Finches can interbreed - or hybridize - and do so on several of the islands where there are many finch species living together.

I'm not a biologist, nor am I an expert on interbreeding of finches (either). I simply try to do research before I make a statement.

-- Jeff

Shane · #28 (**permalink**) 10-20-2005, 10:30 PM

As do I, when I feel like reading pages and pages of text, which isn't at the moment :P

jasonW · #29 (**permalink**) 10-24-2005, 09:14 AM

yes I deeply believe he is right, it would be logical and they keep noticing that we change 'evoluate' all the time, we get taller from a generation to another, Our head shape is changing too, our forehead is incressing.... So i guess that is few hundreds of years we won't look like we do today either....

zteccc · #30 (**permalink**) 10-25-2005, 05:45 PM

Quote:

Originally Posted by jasonW

yes I deeply believe he is right, it would be logical and they keep noticing that we change 'evoluate' all the time, we get taller from a generation to another, Our head shape is changing too, our forehead is incressing.... So i guess that is few hundreds of years we won't look like we do today either....

We get taller, in some nations, societies and peoples, but in others we don't. Could there be another factor? For example, could we be better nourished today than we once were? Could the size difference be just a standard variation provided by our genome? Such physical traits could easily be explained without evolution, and in fact, we find that the human genes aren't appreciably different worldwide, so despite the variance in physical size, it appears that the genes are the same. In short, we haven't evolved to be taller, we're simply expressing a variation in the given genome.
According to Occam's razor, the hypothesis with the least assumptions needed is the one that science should choose. Clearly, an evolutionary change to explain height (one that we can't see when examining the genes in various cultures) is a greater assumption than simply better nourishment and existing gene variation.

Nonetheless, if your faith is based in Evolution, good luck with that.

-- Jeff