Janice Boekhoff
 

Dinosaur to Bird Evolution, Part 2

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 ID 30870701 © Procyab | Dreamstime.com

Last week, we discussed some of the problems with the hypothesis of dinosaur to bird evolution. If you’re still with me, thanks for hanging in there through these longer, more technical (and hopefully interesting) posts. To see the post from last week, click here. Now on to a few more problems with the idea of dinosaurs changing into birds:

1)      Bird walk/lungs

Birds have a distinctive walk. We’ve all seen it and my kids do a perfect impression of a pigeon. Birds walk from the knee down because their upper leg bone remains firmly in place to support their air-sac lungs. Dinosaur legs and lungs are very different. No dinosaurs have fixed femurs like birds do. In particular, the Theropods, which birds supposedly evolved from, had moving femurs and therefore couldn’t support air-sac type lungs. Also, the dinosaur lung has a structure and physiology much closer to reptilian creatures than to birds.

2)      Warm-blooded versus Cold-blooded

Living reptiles are almost exclusively cold-blooded (meaning they take on the same temperature as their surroundings), while living birds are warm-blooded (meaning they maintain a constant temperature, like us). And birds have exceptionally high body temperatures due to a high metabolic rate. Originally, dinosaurs were thought to be cold-blooded like reptiles, but recently many paleontologists have re-considered. Some now suggest dinosaurs were warm-blooded. Is this because they want to conform to the dinosaur to bird hypothesis? Or maybe they’ve watched Jurassic Park too many times? (Hey, I can say it because it’s my favorite book/movie). Unfortunately, no clear evidence exists to support the warm bloodedness of dinosaurs. In fact, no evidence exists to assume they were cold-blooded either, except the fact most of them resemble today’s cold blooded reptiles. So the debate about dinosaur metabolism rages on.

3)      Bird hipped versus Lizard Hipped

Dinosaurs are typically grouped into two categories based on the structure of their hips. The bird hipped dinosaurs, called ornithischians, have a pubic bone directed to the rear (as in most birds), while the lizard hipped, called saurischians, have their pubic bone directed to the front (as in most mammals). This would probably lead you to assume that bird hipped dinosaurs are the ones which gave rise to the lineage of birds, right? Wrong. Bird hipped dinosaurs resembled reptiles, while the lizard hipped dinosaurs looked more like birds. Paleontologists believe the fleet-footed Theropod group were the ancestors of modern birds, such as T-Rex and Velociraptor (from Jurassic Park fame). These dinosaurs have hips that resemble lizards, not birds. Does it make sense that birds would evolve from the lizard hipped dinosaurs as is claimed?

As a small aside, Velociraptor was not nearly as big as they made it look in the Jurassic Park movies. I understand why they enlarged him—for dramatic effect—but a typical Velociraptor only got up to 7 feet long (including its tail). Its body would have been about the size of a turkey.

There are many reasons to be skeptical of the dinosaur to bird evolutionary hypothesis, not the least of which is that the Bible says it happened a different way. Genesis 1 makes it clear that winged creatures were created by God on Day 5 and land animals (which would include dinosaurs) were created on Day 6. The Bible tells us birds were actually created before dinosaurs. Knowing this doesn’t make these creatures any less fascinating to me. The fact that God personally designed every aspect of their physiology makes them that much more amazing.

What do you think? Are you surprised by some of the evidence? Does any of this change what dinosaurs mean to you? Do you still have questions? Ask them and I’ll do my best to get answers.

Additional Resources: Quad City Creation Science Association, http://www.qccsa.org, Answers in Genesis, https://answersingenesis.org/dinosaurs/feathers/did-dinosaurs-turn-into-birds/

 

 

 

Fun Science Fact

Iguanodon Dinosaur photorealistic representation, side view.
 
ID 34872791 © Leonello Calvetti | Dreamstime.com

One of the things I love most about science is the constant learning and refinement of theories. In the historical sciences, like paleontology, this learning and refinement comes from two different sources: new discoveries and re-interpretations of old discoveries. To illustrate, I’d like to tell you the story of Iguanodon, one of the first dinosaur fossils to be scientifically described.

Iguanodon was found in 1822 by Mary Ann Mantell. Her physician husband, Dr. Gideon Mantell, gave the first written description of the creature in 1825. Iguanodon’s thumb spike was thought to be a horn on the forehead, making him more of a dino rhino. This mistake was corrected in 1878 when paleontologist Louis Dollo unearthed thirty-eight nearly complete Iguanodon skeletons. From this find, Dollo realized the spike belong on the thumb. He also discovered that Iguanodon’s back legs were much longer than the front and its tail was thick and heavy. These discoveries led to the modern interpretation of Iguanodon as able to stand on just its back legs or on all four if necessary.

It amazes me how advances in science bring us that much closer to understanding how God made these incredible creatures.

Reference: Ross, Marcus. Building a Better Dinosaur. Answers Magazine, Oct-Dec 2013, 8(4), p. 56-61.

Dinosaur to Bird Evolution, Part 1

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 ID 32027033 © Skripko Ievgen | Dreamstime.com

I have loved dinosaurs since I was a kid. I know, it’s weird. Because I’m a girl and I’m not supposed to love big, scaly critters with lots of teeth, but that’s okay, I’m fine with being weird (used to it, in fact). So, out of my love and devotion for dinosaurs, I have decided to call the month of May, Dinosaur Month on my blog.

Yes, I am aware that International Dinosaur Month is in October (although nobody seems to know who started this), and National Fossil Day is also in October (Oct. 15th), but I don’t want to wait. And it’s my blog, so you can’t stop me (no, I’m not sticking my tongue out).

If you happen to not like dinosaurs, you can still visit here on Mondays for the devotions (I can’t do all this month’s devotions about dinosaurs, sorry, it’s just too hard). Or you can feel free to visit here again in June, I won’t hold it against you.

Now, on to dinosaur related things. In school, I remember being taught about the general theory of evolution when I was pretty young, maybe in grade school, but certainly by junior high. And it actually made me love dinosaurs more. To think they had one ancestor, from a group called the Archosaurs, whose DNA changed and morphed into all the different amazing creatures we see at dusty dig sites or in museum displays. The idea itself seemed fantastical, and I love ideas.

The hypothesis of dinosaurs changing into birds came into fashion sometime while I was in college. I accepted it without question. For me, it meant that in a small way dinosaurs lived on, that somehow they outsmarted the gigantic meteor or the climate change or whatever actually killed them all off.

Skip ahead many years and I became a Christian. I continued to believe in evolution for several more years until I took a church class about creationism. I went into that class with the attitude of “prove this creation stuff to me.” And I was surprised by the evidence. In the next several posts, I’d like to share some of this evidence as it relates to dinosaurs. Some of this information has come from classes I’ve taken with creation scientists, some from creation magazines, and some of it from a presentation prepared by Helmut Welke, President of the Quad Cities Creation Science Association (thanks, Helmut). For more on the Quad Cities Creation Science Association, visit their website, http://www.qccsa.org/.

I’ll do my best to keep this down to earth because I’m sure most of you out there aren’t geologists. So, here are a few of the issues with the theory of dinosaur to bird evolution:

1)      Lack of transitional forms

This means scientists don’t see bird-dinos or dino-birds. If evolution gradually changed dinosaurs into birds, there should be intermediate forms between the two. These transitional forms just aren’t found in the fossil record. Back in the day of Darwin, paleontologists said we simply hadn’t found enough fossils and that transitional forms would turn up. Millions of fossils later, we still have no transitional forms.

Archaeopteryx is sometimes heralded as the missing link between dinosaurs and birds, but there isn’t any evidence this animal was anything more than a bird. It has the characteristic longer forelimbs and shorter hind limbs of a bird, but its supposed dinosaur ancestors show no evidence of their body proportions transitioning in this way.

A few dinosaur fossils have been found with fuzzy material on the bone, which some paleontologists have interpreted as left over feathers. However, further study has shown this material to be fossilized collagen filaments from skin not feathers.

2)      Feathers versus scales

Feathers differ markedly from scales in structure and growth. Feathers grow from tube-like follicles similar to hair follicles and are attached at knobs on the bone. Scales are not individual structures like feathers, but rather comprise a continuous sheet on the surface of the body. When scales shed, they shed as an entire sheet. In contrast, feathers grow and are shed in matched pairs. The structure is very different, as well. The feather vane is made up of hundreds of barbs, each bearing hundreds of barbules interlocked with tiny hinged hooks. This structure is much more complex than the relatively simple structure of reptilian scales. Is it reasonable to believe one evolved into another?

3)      Dinosaur digits

At first glance, dinosaur and bird hands look similar in that they both have three fingers, but the problem is they aren’t the same three fingers. As the embryo develops in both birds and dinosaurs, two of the five fingers are lost and three are retained. Dinosaurs retain digits one, two and three (digit one is the thumb), while birds retain digits two, three and four. So, birds and dinosaurs have mismatched fingers. If they evolved from each other, you’d expect their fingers to have evolved together, as well. This difference suggests it’s almost impossible for them to be related.

In the post next week, I’ll discuss more problems with the hypothesis of dinosaur to bird evolution. For now, what do you think? Does it sound possible for dinosaur scales to evolve into bird feathers? How would you account for the difference in finger development?

Additional Resources: http://www.answersingenesis.org/articles/nab/did-dinosaurs-turn-into-birds

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