Thursday, May 1, 2008

Solving the "Dinosaur Dilemma"

About ten days ago I read an article on my friend Elles's blog. It was titled, "A preschoolers road to unbelief." She basically told about how her preschool belief in God was shattered when she could not find out why God if he were protecting the dinosaurs why he would let them go extinct (she has more complex reasons for being an atheist now of course). Well I gave what my response would have been had she asked me at that time. She replied, and soon a conversation on dinosaurs had started. Although it shifted to why did God take a 160 million year detour in evolving mammals who would become our ancestors to make giant lizards which would die off anyway. The so called "Dinosaur Dilemma" although it borders on facetious when I think about writing an article addressing it I feel it must be addressed. She has used the dino dilemma at least two times on her blog when addressing a theistic evolutionist.





Now first of all being that I don't intend to write an essay on this topic I'll try to keep this post a s short as possible.





Now to begin, lets start with a short introduction. The proto-mammals that existed for most or all of the mesozoic era (which lasted 186 million years between 251 Mya and 65 Mya) evolved from nifty creatures known as therapsids. Therapsids were mammal -like reptiles (the earliest could have been thought of as naked lizards with no hair or scales). They were mammal-like in the sense that they show signs of lactation (feeding their children mother's milk, also paleontologists have suggested it was orignally used for keeping eggs moist). The late therapsids (such as cynodonts and theriodonts) could have been easily mistaken for mammals they had hair, lactation, as well as a near-mammalian jaw and middle ear. Also some therapsids had erect limbs. Today and back then lizards have sprawling limbs (meaning their legs are spread out from their body). Today most mammals have erect limbs (meaning their limbs are direclty below their bodies supporting them like pillars on a building).



The evolution of erect limb structure was every erratic and slow, in fact mammalian evolution was quite slow. Therapsids were the dominant terrestrial lifeform in the permian period (between about 299 Mya and 251 Mya). Then about 251 million years ago, something terrible happened.



The Permian-cretaceous mass extinction, it is not agreed on what caused the mass extinction but what did happen is that 96% of sea dwelling species and 70% of land dwelling vertebrates went extinct. It was by far the worst mass extinction earth has gone through yet. This devastated the therapsids, only theriodonts, theracophalians, and cynodonts survived. All other therapsids died out. This also led to the saurapsids gaining dominance and taking over the planet, the archosaurs who include dinosaurs, pterosaurs, and plesiosaurs filled all the niches which the therapsids had previously filled reducing the therapsids to nocturnal insectivores who were often no larger then rats. Now interestingly enough the mass extinction and reptilian takeover aided mammalian evolution;

--since they were small they became warm-blooded so they could sustain their body heat in the cool of the night

--the development towards differentiated teeth with precise occlusion (the arches of the teeth coming together in symmetry) was given a boost because they needed to be able to catch arthropods and crush their exoskeletons.

--an acute sense of hearing and smell became more necessary so as a result the mammalian ear evolved faster then it otherwise would have.

--and the evolution of the mammalian skull was accelerated as a whole.

--Because the jawbones came together further forward on the skull this allowed for less restriction on brain siz allowing the brain to become larger.

After this one of the survivors, the cynodonts, ended up being the ancestors of all mammals today. Cynodonts survived into the mid-cretaceaous period, by the end it had all the characteristics of a mammal. The small bones which are in located in the jaw in reptiles were in its ear (as expected in mammals), it had fur, and it had more mammalian dentistry. It still layed eggs however (which monotremes, or egg-laying mammals still do). Of course this isn't the end of it. The first true mammals did not appear until 125 Mya, and when they did they were marsupials (meaning their offspring were born in pouches). now this was a step but they were not the mammals that would lead to us. The next mammals to evolve were none other then placental mammals (I'll let you guess what those are). And guess what species relevant to humans is a placental mammal; humans themselves. Placental mammals began to diversify 110 Mya splitting off into different groups, then 65 Mya something strangely wonderful happened. It is bad because it was another mass extinction; but this time dinosaurs, plesiosaurs, and pterosaurs (and pretty much anything larger then a house-cat) went extinct. This was was sadly fantastic because now the newly evolved mammals took over and ten million years later they dominated the earth. One group of these mammals inhabited the trees and developed intelligence, then 5 Mya one group broke of and became hominids which led to us (according to the evolutionary theory).

Do you see it? Do you see the hand of God? If the permian extinction had not occurred mammal evolution would have taken much longer, or mammals may have never evolved, then humans would have never arrived. God sent the permian-cretaceous extinction event to speed up mammal evolution and then the cretaceous-tertiary extinction event to allow mammals to populate the earth and lead the way to us, then he revealed himself to us making us in his own image.

Thank God for evolution.

15 comments:

splendidelles said...

"We are here because one odd group of fishes had a peculiar fin anatomy that could transform into legs for terrestrial creatures; because the earth never froze entirely during an ice age; because a small and tenuous species, arising in Africa a quarter of a million years ago, has managed, so far, to survive by hook and by crook. We may yearn for a higher answer -- but none exists."
-- Stephen Jay Gould

There are a lot of things that could have happened over the course of evolution that would keep us from being here, yes. But it's not entirely impossible that another evolutionary pathway would have led to us.

Really, it is remarkable that we're here, but there's no evidence that evolution was guided to us.

In evolution, there are some things you can predict, but a lot is quite unpredictable.

By saying the Permian Extinction was necessary for mammal evolution, you're making a new hole... Why did the Judeo-Christian god (or whatever god could've been guiding evolution) let the Permian happen when he could have just guided the animals directly toward mammalian traits a lot faster?

splendidelles said...

Grr... I've been at school too long... I meant that another evolutionary pathway could have led to a completely different conscious species.

Created Rationalist said...

Very True splendid elles but first of all, my argument was that God was speeding upo the process of mammal evolution with the permian mass extinction when he could have done it at the slow progressive rate he was going (so thats how he sped up the evolution of mammalian traits).

And true it could have led to other conscious species but not to us which is what God wanted.

Created Rationalist said...

*up not upo

Also it depends on how closesly God was guiding evolution (whether he was only influencing conincedences or directly guiding natural selection as each species evolved).

I do not think God was necessarily guiding so closely that he was the ghost behind Natural Selection, more he was the ghost behind what influenced natural selection.

Evolved Rationalist said...

Ahhh! The brain trying to reconcile the Bible and evolution hurts so bad!

Created Rationalist said...

I am not reconciling the bible with evolution in this article only God.

If you have an actual comment I will be happy to respond

Rev. Reed Braden said...

Welcome to my RSS Feed!

Glad to see there's a Christian out there who's vocally supportive of evolution.

(Takes in a breath of fresh air.)

gaytheist said...

Well... not my RSS feed... but my RSS feed reader.

You know what I mean.

In the beginning GOD said...

It seems so convoluted to believe in all these steps with God "ghosting" the process in some way to come up with what He wanted as an end result. Why not just created us in His image in the first place?

Created Rationalist said...

In the beginning God; he could have done it however he wanted, for some reason apparently he chose to use evolution

Chris said...

Since you are an "old earth" advocate I was wonder what your answers are to the "young earth" arguments of:

1 moon drift
2 earth rotation speed
3 magnetic field decay
4 erosion rates
5 chemical influx into the oceans, 6 ocean salinity

Since all of these seem to put a serious time constraint on the age of the earth how could evolution take place in such a short ammount of time?

Created Rationalist said...

Hey Chris,
1 moon drift

The moon is receding at the speed of 3.8 inches per year, the moon is 12-15 billion inches from earth, do the math

15,000,000,000/3.8 = 39,473,684,210
or it would become a problem in 39 billion years

2 earth rotation speed

Earth I believe is slowing down about 2.2 seconds every 100,000 years, 4 billion years ago no life had been created yet.

3 magnetic field decay

there is evidence of magnetic reversals in rocks

4 erosion rates

Young Earth creationists who use this argument fail to appreciat erosion rates are not constant and vary from environment ot environment

5 chemical influx into the oceans,

I haven't heard this argument before, could give me some more information on it?

6 ocean salinity

Young Earth Creationists who use this argument fail to take into account that the salt influx into the oceans is not constant using tihs logic if there re three feet of snow on the ground outside your house and you observe that the average snowfall around the world creates three feet a day then the earth must only be three days old.

ian said...

Don't you think it's a little presumptuous to say that God was the reason why the permian extinction happened? I'm not saying that he wasn't. Maybe he was, but there is no way to know.

Besides, when the Bible says that we were "created in His image," I am pretty sure the scripture is talking about something spiritual and not something physical. I mean, why would God prefer a mammalian creature vs. a reptilian creature?

Created Rationalist said...

It may be, but is there any reason to say its not?

I didn't say humans were created in his physical image I was referring to his spiritual image.

That is an interesting question Ian, well I am not sure if there is any reason God chose mammals over reptiles he simply did because it led to us. On the other hand he may have chosen mammals because mammals are capable of having emotions and concepts such as love, altruism etc. Reptiles have more basic instincts and might be incapable of loving God or each other. Of course God could do whatever he wanted, he could have made us cephalopods if he wanted to.

Chris said...

CR,

Our oceans contain concentrations of Aluminum, Antinomy, Barium, Bicarbonate, Bismuth, Calcium, Carbonates, Chlorine, Chromium, Cobalt, Copper, Gold, Iron, Lead, Lithium, Manganese, Magnesium, Mercury, Molybdenum, Nickel, Potassium, Rubidium, Silicon, Silver, Sodium, Strontium, Sulfate, Thorium, Tin, Titanium, Tungsten, Uranium, and Zinc. The river systems add to these concentrations at fixed apparent rates. Comparing the amounts already in the oceans with the rates at which more are being dumped, indicates the earth, as well as its river systems and oceans, are fairly young.