Why do human embryos start with tails and gills?

[joshua 1 9]

Anyone open for a discussion on this?

 

[Loudmouth]

Anyone open for a discussion on this?

It is a carryover from our tailed and gilled ancestors. Also, we don't develop gills, but we do have gills slits, or pharyngeal slits as they are sometimes called.

 

[Zosimus]

Anyone open for a discussion on this?

A human embryo has neither gills nor a tail. Certainly it has pharyngeal pouches, but these develop into the facial features and form internal structures such as tonsils, chewing muscles, the inner ear, etc. and have nothing to do with breathing. Human lungs develop from the gastrointestinal tract.

Similarly, even humans born with structures that appear superficially to resemble tails do not actually have tails. There is never any sign of bone structure, intelligent movement, etc. Many born with "tails" actually suffer from spina bifida, a congenital defect.

 

[Loudmouth]

A human embryo has neither gills nor a tail. Certainly it has pharyngeal pouches, but these develop into the facial features and form internal structures such as tonsils, chewing muscles, the inner ear, etc. and have nothing to do with breathing.

There is definitely a post-anal tail. There is no doubt about that.

However, you are correct about the pharyngeal slits. These same slits do develop into gills in fish.

Similarly, even humans born with structures that appear superficially to resemble tails do not actually have tails. There is never any sign of bone structure, intelligent movement, etc. Many born with "tails" actually suffer from spina bifida, a congenital defect.

Sometimes, humans keep developing these tails with apoptosis removing them during embryonic development. The result is a tail with bones.

That is an x-ray of a real human with a real tail with real bones (c1-c3 for caudal 1-3).

We even still have the extensor coccygis muscle that spans two fused vertebrae in the tail bone, but is used to lift the tail in other species. A bone that spans a fused joint, something we call a vestigial feature.

 

[SkyWriting]

something we call a vestigial feature.

No we don't.
That phrase is used in
mental health circles.

 

[SkyWriting]

There is definitely a post-anal tail. There is no doubt about that.

A post-anal tail is a muscular region of the body that extends
posterior to the anus. The post-anal tail may aid locomotion
and balance. Chordate

https://zfin.org/GO:0036342

 

[Loudmouth]

A post-anal tail is a muscular region of the body that extends
posterior to the anus. The post-anal tail may aid locomotion
and balance. Chordate

https://zfin.org/GO:0036342

And there it is (the section of the vertebral column directly above the 2 mm bar):

 

[Loudmouth]

No we don't.

Yes, we do.

 

[SkyWriting]

Anyone open for a discussion on this?

One of the arches becomes your jaw. There are no slits.

 

[Loudmouth]

One of the arches becomes your jaw. There are no slits.

In fish, those same arches become gills. We have the same basic embryological features early in development because of our fish ancestors.

 

[SkyWriting]

In fish, those same arches become gills. We have the same basic embryological features early in development because of our fish ancestors.

So, now fish don't have jawbones?
I wonder here you get this stuff.

 

[Zosimus]

There is definitely a post-anal tail. There is no doubt about that.

However, you are correct about the pharyngeal slits. These same slits do develop into gills in fish.



Sometimes, humans keep developing these tails with apoptosis removing them during embryonic development. The result is a tail with bones.

That is an x-ray of a real human with a real tail with real bones (c1-c3 for caudal 1-3).

We even still have the extensor coccygis muscle that spans two fused vertebrae in the tail bone, but is used to lift the tail in other species. A bone that spans a fused joint, something we call a vestigial feature.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263034/

"True human tail arises from the most distal remnant of the embryonic tail. It contains adipose tissue, connective tissue, central bundles of striated muscle, blood vessels and nerves and is covered by skin. Bone, cartilage, notochord and spinal cord are lacking. It can move and contract and occurs twice as often in males as in females. None of our patients showed any movement of the tail."

http://www.indianpediatrics.net/july1999/july-712-713.htm

"A true tail in human is vestigial and never contains vertebrae in contrast to vertebrate animals. It has been suggested that true tail is a dermal appendage coincidentally located in the sacrococcygeal region(1). In most patients it is located in the sacrococcygeal region and can be located 1.5 cm to one side. Though anomaly occurs in both sexes, a slight predominance in males is known(8). It affects all races(8). Familial cases have been reported(3). Caudal appendages are reported also to be associated with other congenital anomalies in 29% of cases(9) and spina bifida has been the most frequent coexisting anomaly."

 

[Papias]

Source? So, now fish don't have jawbones?
I wonder here you get this stuff.

A source would be most university biology/development courses.

But a cheaper, quicker and funner alternative is the book that Dr. Shubin wrote for a regular audience, Your Inner Fish - which makes a great Christmas gift. I've read it - highly recommended:


No, one becomes the jaw, the others gills. This is because fish jaws, (and therefore our jaws) evolved from gill arches.

In Christ -
Papias

 

[Loudmouth]

So now fish don't have jawbones?

They don't have the additional jawbones that tetrapods have.

 

[Loudmouth]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263034/

"True human tail arises from the most distal remnant of the embryonic tail. It contains adipose tissue, connective tissue, central bundles of striated muscle, blood vessels and nerves and is covered by skin. Bone, cartilage, notochord and spinal cord are lacking. It can move and contract and occurs twice as often in males as in females. None of our patients showed any movement of the tail."

http://www.indianpediatrics.net/july1999/july-712-713.htm

"A true tail in human is vestigial and never contains vertebrae in contrast to vertebrate animals. It has been suggested that true tail is a dermal appendage coincidentally located in the sacrococcygeal region(1). In most patients it is located in the sacrococcygeal region and can be located 1.5 cm to one side. Though anomaly occurs in both sexes, a slight predominance in males is known(8). It affects all races(8). Familial cases have been reported(3). Caudal appendages are reported also to be associated with other congenital anomalies in 29% of cases(9) and spina bifida has been the most frequent coexisting anomaly."

Human tail with vertebrae:

http://www.talkorigins.org/faqs/comdesc/section2.html#atavisms_ex2

 

[SkyWriting]

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3263034/

"True human tail arises from the most distal remnant of the embryonic tail. It contains adipose tissue, connective tissue, central bundles of striated muscle, blood vessels and nerves and is covered by skin. Bone, cartilage, notochord and spinal cord are lacking. It can move and contract and occurs twice as often in males as in females. None of our patients showed any movement of the tail."

http://www.indianpediatrics.net/july1999/july-712-713.htm"A true tail in human is vestigial and never contains vertebrae in contrast to vertebrate animals. It has been suggested that true tail is a dermal appendage coincidentally located in the sacrococcygeal region(1). In most patients it is located in the sacrococcygeal region and can be located 1.5 cm to one side. Though anomaly occurs in both sexes, a slight predominance in males is known(8). It affects all races(8). Familial cases have been reported(3). Caudal appendages are reported also to be associated with other congenital anomalies in 29% of cases(9) and spina bifida has been the most frequent coexisting anomaly."

It does not sound very fishy to me.

 

[SkyWriting]

Human tail with vertebrae:

http://www.talkorigins.org/faqs/comdesc/section2.html#atavisms_ex2

Talk Origins is on par with The Institute for Creation Research in the Science community.

 

[Loudmouth]

It does not sound very fishy to me.

Forgot to mention the Agnathans. There are fish without jaws, and this is the ancestral condition for fish.

https://en.wikipedia.org/wiki/Agnatha

 

[Loudmouth]

Talk Origins is on par with The Institute for Creation Research in the Science community.

They actually tell the truth at TalkOrigins. Not even close to the same thing.

 

[SkyWriting]

They don't have the additional jawbones that tetrapods have.

How many more do we all have again?