Transitional forms in existence today

Message 16 of 62 (623761) 07-13-2011 6:48 AM

Reply to: Message 12 by Portillo 07-13-2011 5:40 AM

My God, sometimes the creationist ability to confound things borders on genius.

Do you care to tell us who actually used the phrase "the maintenance of stability within species" (it wasn't Dawkins), and as a bonus question, give us the full context so we can see what was actually meant?

And what was the source and context of the Richard Dawkins' quote?

All species are transitional. Both Gould and Dawkins are aware of that and would have no reason to contradict what they believe to be true.

--Percy

Message 17 of 62 (623764) 07-13-2011 7:15 AM

Reply to: Message 16 by Percy 07-13-2011 6:48 AM

It's kinda true that many species are transitional - obviously not all, because any species that goes extinct is not - but it's a broader meaning of the word 'transitional' than the one being discussed. In general usage, when we talk about transitionals without context what we're talking are transitionals specifically between distinct higher taxonomic groups.

Message 18 of 62 (623765) 07-13-2011 7:40 AM

Reply to: Message 9 by pandion 07-13-2011 12:52 AM

Think you might need to check your source, for that one.

Message 19 of 62 (623766) 07-13-2011 7:43 AM

Reply to: Message 15 by Chuck77 07-13-2011 6:25 AM

Please tell me this is clever use of Poe's Law.

Message 20 of 62 (623769) 07-13-2011 9:19 AM

Reply to: Message 1 by peter1985 07-12-2011 11:17 AM

1) Polar bear http://en.wikipedia.org/wiki/Polar_bear
Clearly a land quadripede, but hunts in water and spends quite a lot of time in water. Already developed some adaptations for cold water like greesy fur. This species might eventualy transform into:

2) Seal http://en.wikipedia.org/wiki/Sea_Leopard
This is an example of mamal wich is gone half way trough transformation from a quadripedal carnivore to something like a fish-like animal. Another animal, but mammal, bird instead is going through similar phase:

3) Penguin http://en.wikipedia.org/wiki/Penguin
Both penguin and seals are nice examples of "half-way" adaptation. Neither land or aquatic, they can both walk and swing, but aren't particulary good at either.

4) Manatee http://en.wikipedia.org/wiki/Manatee
This is a mammal even more adapted to marine life, giving birth in water, but still not 100% fish-like, like a dolphin or whale

So, above are example of modern land to water transitions. Whale and dolphin ancestors probably had a similar way of life some time in past.

5) Flying squirrel http://en.wikipedia.org/wiki/Flying_squirrel
Is an example on "how did bats developed wings". Eventualy this spieces might evolve into a flying mammal similar to bats

6) Walking fish http://en.wikipedia.org/wiki/Walking_fish
Will it's descendants repeat again an epic jurney from water to land? If so, this fish is transitional form from a fish-like to land-crawling animal.

All above animals are nice examples because they're going through changes which already occured in past to other spieces, so we can clearly correlate and recognize various stages.
But future will give us many more variations, wich we won't witness, and it's hard to immagine. It is safe to say that most of spiecies are transitional into something different.
There are some examples, like sharks, who live in non-changing enviroment - open sea - who will probably look the same for a long time. But all others who live in always-changing enviroment will continue to change to best fit their habitat.

These are just examples from top of my head, if I think of something else, I'll post more.

Message 21 of 62 (623770) 07-13-2011 9:27 AM

Reply to: Message 16 by Percy 07-13-2011 6:48 AM

Source - NOW with Bill Moyers. Transcript. December 3, 2004

Context:

quote:

---

MOYERS: Is evolution a theory, not a fact?

DAWKINS: Evolution has been observed. It's just that it hasn't been observed while it's happening.

MOYERS: What do you mean it's been observed.

DAWKINS: The consequences of. It is rather like a detective coming on a murder after the scene. And you… the detective hasn't actually seen the murder take place, of course. But what you do see is a massive clue. Now, any detective…

MOYERS: Circumstantial evidence.

DAWKINS: Circumstantial evidence, but masses of circumstantial evidence. Huge quantities of circumstantial evidence. It might as well be spelled out in words of English. Evolution is true. I mean it's as circumstantial as that, but it's as true as that.

---

Message 22 of 62 (623778) 07-13-2011 11:00 AM

Reply to: Message 18 by Larni 07-13-2011 7:40 AM

quote:

---

Think you might need to check your source, for that one.

---

Message 23 of 62 (623779) 07-13-2011 11:41 AM

Reply to: Message 1 by peter1985 07-12-2011 11:17 AM

Evolution also involves natural selection. It is a two step process where random mutation produces variation within the population and natural selection reduces the number of deleterious mutations while increasing the number of beneficial mutations.

Your question can take on many meanings, so you may need to clarify exactly what you are looking for.

Do you mean to ask why we don't see transitional features that carried over from past evolutionary events? If so, then your question is easily answered. Let's use mammals and reptiles as an example. From the fossil record we know that modern mammals evolved from ancient reptiles. This means that modern reptiles and modern mammals share a common ancestor. Both lineages branched off at this point, and each lineage continued to evolve. In the mammal lineage, many of the branches died off. However, there is one mammalian lineage where these transitional features have been preserved: the monotremes. The most famous species of monotreme is the platypus. In this species we see a very primitive lactation system, a body temperature much cooler than other mammals, and leathery eggs like those laid by modern reptiles. As you can imagine, not all transitional features are going to be preserved in a lineage over time.

There are two things to keep in mind:

1. All lineages evolve. Reptiles did not stop evolving after mammals branched off. The same goes for all of the mammalian lineages that branched off after they evolved from reptiles.

2. Extinction happens. Lineages where transitional features can still be seen are at risk for extinction, as much as any other lineage. One of the reasons we do not see preserved transitional features is that those lineages went extinct.

Message 24 of 62 (623791) 07-13-2011 1:28 PM

Reply to: Message 23 by Taq 07-13-2011 11:41 AM

Before I started my research towards a conviction of the topic I decided the wisest way to do it was to approach it with an open mind and as little a bias as possible . Consequently, I read a lot of intelligent design/creationist literature, much of which I have learned over the past year is scientifically inaccurate or misconstrued science. I remember one such book had a chapter devoted to the alleged lack of transnational forms as evidence for a creator and charged that if random mutation was the mechanism for evolution there would be more species "in flux" than wholly formed species. I now see the fallacy that the subjectivity in that argument creates.

Message 25 of 62 (623797) 07-13-2011 2:19 PM

Reply to: Message 24 by peter1985 07-13-2011 1:28 PM

Well, there's your problem...

Message 26 of 62 (623806) 07-13-2011 2:52 PM

Reply to: Message 24 by peter1985 07-13-2011 1:28 PM

Languages are a good analogy to use when trying to understand how evolution works. As you may know, the Romance Languages are a language group that "evolved" from Latin. Here is an idealized lineage for the Romance languages:

So you may ask why don't we hear anyone speaking a transitional language. If you went back 1,000 years you would be asking the same question even though those languages 1,000 years ago were the transitional langages between modern languages and vulgar latin. Also, the descendants of those who spoke proto-Italian, for example, are not speaking modern Italian.

If humans evolved from a common ancestor with other apes why don't we see any transitional hominids today? For the same reason that no one speaks Middle English today.

Edited by Taq, : No reason given.

Message 27 of 62 (623810) 07-13-2011 3:58 PM

Reply to: Message 22 by pandion 07-13-2011 11:00 AM

I do beg your pardon.

Message 28 of 62 (623815) 07-13-2011 5:02 PM

Reply to: Message 15 by Chuck77 07-13-2011 6:25 AM

Shucks Chuck, have you not been paying attention to the content of the scientifically literate posts in any of the topics you've been participating in? That's not at all what transitional means, and you'd know that if you'd read any other of the replies in just this topic here. I don't mean to sound critical, but you've actually been better than most at taking an honest look at the evidence you've been exposed to here, and I had hoped that you were having your eyes open to the faults in what you'd be told in the past by the scientifically illiterate. What happened?

I also note that you've taken a very defensive tone in your debate with Straggler. Is any of that bleeding over into your post here, even though the topics are quite different?

I've been reading The Dawkins Delusion? as you suggested, but it's taking some time because I have to keep stopping to re-read the relevant passages in The God Delusion. Hard to believe that McGrath's understanding of Dawkins's book is so far apart from what it actually says. In the meantime, I hope that you've been reading some of the books on the facts of evolution that I listed for you. They would make topics like this much clearer for you.

I never meant to say that the Conservatives are generally stupid. I meant to say that stupid people are generally Conservative. I believe that is so obviously and universally admitted a principle that I hardly think any gentleman will deny it.
- John Stuart Mill

Message 29 of 62 (623820) 07-13-2011 5:24 PM

Reply to: Message 15 by Chuck77 07-13-2011 6:25 AM

What transitional mammalian features do penguins have?

Message 30 of 62 (623824) 07-13-2011 5:32 PM

Reply to: Message 24 by peter1985 07-13-2011 1:28 PM

To be precise, it's a false dichotomy. An Archaeopteryx was an intermediate form but it was also a "wholly formed" Archaeopteryx.