Help solving the Improbable: Hyena to Whale

[acuodancer]

Hi,

 

I'm an atheist and I believe Evolution to be true. I'm having a debate with a creationist and one of his argument is about how improbable macro-evolution is. This is a quote from his argument:

 

Have you read about theories for the origin of the whale? Two major theories are a Hyena species and a Hippo species.

 

Taking the Hyena into consideration, the minimum number of traits that would have to be altered BY CHANCE are:

1. Dorsal fin development

2. Bony tail into a cartilaginous fluke

3. Teeth into baleen filter

4. Hair into blubber for insulation

5. Nostrils from nose to top of head, disconnect from mouth and formation of a muscular flap

6. Front legs into pectoral fins

7. Body size from 150 pounds to 360,000 pounds

8. External ears to high-pressure ears.

9. Loss of back legs.

 

If you've done Permutations and Combinations, the number of DNA letters that must be added to change one animal into another can be calculation by the following:

#Of body changes x #Of new proteins needed x #Of Amino acids in each neww protein x 3 new letters of DNA needed for each new amino acid =Total # of DNA letters added/changed.

 

Let's take it hypothetically. If one new proteins directly related to one trait-change, and one protein contains 100 amino acids, then 2700 new letters of DNA would have to be added/changed to that of the hyena. These must be ACCIDENTALLY acquired by the hyena, and correlate to form a functioning animal. The odds of doing this, for each DNA letter would thus be 1/4^2700(since DNA is comprised of 4 letters) I believe you get 1/(364 x 10^1625). With a probability like that ...

 

I don't take biology in school so I'm not really sure about how the copy and cross over process works. As a result, I find myself lacking a solid response to this question.

 

I hope people who are better educated in this aspect can help me to show whether his argument has validity or if it is flawed. Thank you,looking forward to being educated more on this matter.

[Delta1212]

That math is literally garbage even for the mistaken way that the person is trying to calculate the odds.

 

That said, yes, the odds of all of that happening by chance are astronomically small. But evolution isn't random. The mutations are random, but they get filtered by natural selection, which is not.

 

Ok, let's say you want to flip a coin 6 times and get heads every time. There's a 1 in 64 chance of that happening. If we treat each set of 6 flips as a discreet event (rather than just continuously flipping the coin until you get 6 heads in a row), it will take 64 rounds, on average, for you to get your set of all heads.

 

Now let's consider that, in the real world, you're not going to have one animal of a particular species at a time. You're going to have a fairly sizable population all reproducing and mutating at once. So we're going to give you a population of 8 coins to flip at once. This, right here, brings the average number of rounds down to 8. The coin that gets heads flipped 6 times in a row in the first scenario needs to be flipped an average of 384 times. In this situation, the "winning" coin only needs 48 flips. That's pretty good.

 

Now, let's add natural selection. After the first flip, we remove all of the coins that came up tails (roughly half), and the remaining coins "reproduce" and make copies of themselves that we'll treat as sharing the same flip history. So after the first flip, we wind up with 4 coins that came up heads and 4 that came up tails. The tails coins die, so we just have 4 heads. Now the heads coins reproduce, so we have 8 coins that came up heads in the first flip.

 

This happens each flip, and so at the end of each flip, we have 8 coins that are treated as if they'd come up heads every flip thus far. That means that at the end of 6 flips, the end of a round, we'll have our 6 heads in a row. The only way this doesn't happen is if every coin comes up tails at some point, and the odds of 8 coins all coming up tails at once are 1/256. Since there are 6 flips, and thus 6 chances for this to happen, it comes out to a roughly 2.5% chance.

 

That means that you have a ~97.5% chance of getting your set of 6 heads in a row on the first round, compared with a ~1.5% chance of that happening by chance the way your friend attempted to calculate it.

 

So you can see, natural selection skews the odds a bit when there is a selection pressure towards a particular trait.

 

Each trait doesn't have to appear fully formed, and they certainly aren't all appearing fully formed at once in a single generation. That is what your friend was calculating the odds of, and everyone agrees that the odds of that happening are so remote as to be physically impossible.

 

Instead what happens is that a trait appears that makes the hyena-thing slightly better at swimming. As the population spends more and more time in the water, those who are better swimmers are less likely to drown, more likely to obtain food in the water and less likely to get caught by something that could kill it (either on land by escaping into the water or in the water by being a better swimmer).

 

Each new generation is a population with all of the best traits of the previous generation, and in the environment these animals were living in those traits are more whale-like. This is something that would have happened over many, many generations each of which consisted of a very large population of animals with each generation building on the progress of the last, not something happening to an individual all at once.

 

It'd be like calculating the odds of one guy in an ancient hunter-gatherer society making all of the discoveries and inventions necessary to land on the moon and then declaring that, because it's basically impossible for this person to accomplish the task single-handedly in his lifetime, it is impossible for people to go to the moon.

 

Edit: typo

Edited May 8, 2014 by Delta1212

[pwagen]

Delta1212, if I could +1 you as much as I'd want to, you'd have to get a restraining order on me. Excellent post!

[delboy]

I'm having a debate with a creationist

 

I can't top delta's brilliant answer, but you could just tell him not to be silly and go and look at a seal or a penguin.

[Greg H.]

The argument "it's impossible by chance alone" is not new ammunition in the creationist quiver, and is most famously summed up in this pithy little statement by Fred Hoyle:

 

 

The chance that higher life forms might have emerged in this way is comparable to the chance that a tornado sweeping through a junkyard might assemble a Boeing 747 from the materials therein¹.

 

It is used to attack both abiogenesis and macro-evolution (whatever that is), while supposedly leaving room for evolution on a micro scale. It's use shows that the speaker is either being deliberately disingenuous, or has no real idea how evolution works. As Delta so eloquently pointed out, it ignores the facts of how evolution works, and it makes assumptions about the math that are blatantly incorrect in the first place. It also ignores the fact that given enough castsof the die, the probability of any discrete event happening approaches 100%, assuming the event is possible to begin with.

 

At it's most fundamental level, it's an apologist's argument from incredulity, a logical fallacy, and can be dismissed as such.

 

Also, don't fall for the irreducible complexity² argument either.

 

1: See http://en.wikipedia.org/wiki/Junkyard_tornado for more on the quote and the history behind it.

2. See http://en.wikipedia.org/wiki/Irreducible_complexity

Edited May 8, 2014 by Greg H.