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Whale Evolution (Macro)

 

 

 

 

 

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  Summary

Macroevolution is true

Human evolution is true

Scriptures are not inspired

Theism not believable

It's not about the evidence

World Views In Collision

 

Why Care?

 

 

Feelings.  Red pill - Blue pill

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Vestigial Structures

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DNA Evidence - Insertions

 1. ERVs   2. Transposons

Human Chrom. 2 Fusion

Pseudogenes

Human Lice & Evolution

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Old Testament

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Veritas Super Omnia 

Items

Origine

Vestigial Structures Continued

9. Recurrent laryngeal nerve - Most of the nerves that supply the human body come from the spinal cord.  But the nerves that supply the head come directly from the brain and brainstem and thus are called cranial nerves.  One of these cranial nerves, the 10th, also descends into the chest.  Because it seems to wander throughout the upper body it was named the vagus nerve (from Latin "wandering", as in vagabond).  When examining the nerves in the necks of vertebrates one is struck with a strange arrangement. The voice box, or larynx, is supplied by some nerves that come from the chest instead of the neck. The top of the larynx is supplied by nerves coming off the vagus nerve directly from the neck - the superficial laryngeal nerves.  But the bottom of the voice box is enervated by nerves that seem to come from a needlessly long route. It's as if one were to drive from Los Angeles to Las Vegas by a route that takes you through Brazil. In the giraffe this is taken to the extreme and involves and extra 15 feet tacked onto it's journey. We know it doesn't need to be this way because the superficial laryngeal nerves come directly off the vagus at the level of the larynx and sometimes people are born with a non-recurrent laryngeal nerve.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 What is going on?

     The best way to understand the origin of this anatomy is to look at the embryology of the developing organism.  In humans during the fourth and fifth week of development arches, called branchial arches, form in the neck region. Certain structures will be derived from them later. Specifically, the 4th and 6th arches form some of the major blood vessels and structures. But the 4th branch of the vagus nerve sits behind the 6th brachial arch and as it descends into the chest, this branch of the vagus nerve is dragged with it.  Eventually, the right recurrent laryngial nerve ("recurs" or goes back up the neck in a retrograde manner) must wrap around the right subclavian artery before heading back to the larynx.  The left recurrent laryngial nerve is a little more complicated. When in the womb, the fetus gets its oxygen from mom and not its lungs.  So, there is a shunt between the pulmonary artery and the aorta that allows the lungs (which are useless for oxygenation at this stage) to be bypassed.  This blood vessel, the ductus arteriosis, closes after birth normally and degenerates into a structure called the ligamentum arteriosis.  The left recurrent laryngeal nerve gets hooked by this structure under the aortic arch and passes around it before heading back up the neck to reach the larynx. Again, why is this so?

    The answer lies in fish anatomy. Look at this diagram.   The vagus nerve is on the top with it's branches following the circulatory branches that join the fish ventral and dorsal aortas.  So now we can see why the recurrent laryngeal nerves end up with their strange route and why we can with confidence know that we share a common ancestry with other organisms.  Specifically, in this case our laryngeal nerves are evidence of our past connection to fishes and it is only through an evolutionary view that this makes sense.  Video of giraffe recurrent laryngeal nerve dissection, see here.

The Longest Cell in the Hisory of Life (RLN in a dinosaur)

     

 

10. Wisdom teeth - oral surgeons are often heard stating that there are two kinds of people in the industrial world: those who have had their wisdom teeth extracted as young adults and those who will later, with the potential consequences of infection and nerve damage during the surgery if they wait too long. There is controversy within dental societies, with some arguing to remove these teeth in nearly everyone due to all the common complications, and other studies showing that asymptomatic 3rd molars should be left alone.   What is going on here - why does such a huge percentage of persons have their wisdom teeth removed in developed societies? Many researchers think that our soft modern diet is to blame, and not an alternative explanation that as humans evolved we developed smaller jaws and the third molars did not shrink to match the changes. The key to understanding the wisdom teeth (so called because they usually appear between age 17 and 25 when we are more 'wise') issue is to look not at the third molars but the first and second molars. The first molars erupt at age 6 -7, the second molars at age 12 - 13,  and the third molars usually at age 17 - 21. In many animals that have sequential teeth eruption, the eruptive stages match the life span of the animal and after the last set of molars are ground down, the animal often dies of poor food intake since chewing becomes more difficult, infections set in, and poor nutrition leads to poor health and death. Thousands of years ago, what was an average lifespan for humans? Probably about 30 years. Even in the USA, as of 1900 it was only about 50.  So now we can see that the replacement of our molars followed a life stage of mastication with new molars erupting to keep up with our needs for replacement grinding surfaces. We did indeed grind the molars down so they had enough room in the jaw and were rarely impacted. And we didn't need a 4th or 5th set because we rarely outlived the functional lifespan of the third molars.

 

Human Vestigial stuctures - Video. Your body as a museum of natural history: LINK  (4 min)

 

 

 

II  Other animals  

 

1. Whale and snake pelvis - some species of these animals contain small reminants of pelvis and limb bones that have no or little function currently.  These are best explained as shrunken evolutionary relics.  Even if they were found to have a small function, they are still vestigial since any function, if present, is nearly inconsequential.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Kiwi - a flightless New Zealand bird that has vestigial wings that have shrunk to where they are only nubs now.

 

3. Flightless beetles - such as the weevils in the family Lucanidae have perfectly formed wings underneath fused wing covers that are never used. Why would a designer put flight wings in a beetle and yet they are never to be used?

 

4. Dandelions - these common lawn weeds reproduce without fertilization (apomixis) and yet produce pollen and have flowers which are useless to their reproduction and yet are clearly sexual plant reproductive organs.

 

 

There are many, many more examples in various organisms.  Recall that vestigial structures are not necessarily functionless, but no longer perform the original function they were adapted for.

 

 

References

 

29+ Evidences for Macroevolution

Why Evolution is True. Jerry Coyne

Evolution: What The Fossils Say and Why It Matters.  Donald Prothero

The Top 10 Daily Consequences of Having Evolved (human):  Click here

God's Greatest Mistakes  Link.

Evidence for evolution: kidney development  Link

 

Biomed  6/10

 

 

RECURRENT_LARYNGEAL_2 whale-vestigial-structure pelvis femur