It is an unconfirmed hypothesis at the present time, however, two important points: (1) It is a hypothesis that can be tested and "supported or refuted" (see last sentence), which is always the mark of a good hypothesis; and (2) while the specific hypothesis is unconfirmed, the cellular mechanisms are substantially confirmed and well documented. In fact, the "polyploidization" is one of the widely documented examples of instantaneous speciation that I talked about just recently.
"Split-second of evolutionary cell change could have led to mammals"
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Jan 29, 2023
0
#3
tbwp10 wrote:
It is an unconfirmed hypothesis at the present time, however, two important points: (1) It is a hypothesis that can be tested and "supported or refuted" (see last sentence), which is always the mark of a good hypothesis; and (2) while the specific hypothesis is unconfirmed, the cellular mechanisms are substantially confirmed and well documented. In fact, the "polyploidization" is one of the widely documented examples of instantaneous speciation that I talked about just recently.
Yes, agreed if the playground is only what we can see and measure then it's as good as it gets unless of course what is made was made by something not seen or measurable then no matter how nice it sounds, that is all it is nice sounding.
I don't understand what you're saying
Jan 29, 2023
0
#5
I know, you are looking for how to make it fit with only that which we can see, measure, and weigh but if that isn't the source who cares? Even our coding writing " print ", "Hello World" will not do a darn thing unless the code has controlling features attached to the letters so that using the proper syntax, what you write, will produce what you want. The code has to be designed to work in whatever environment you are working in, be it Windows, UNIX, or something else.
New study...
"Published in the Journal of Cell Science, Professor John Martin (UCL Division of Medicine) thinks a single genetic molecular event (inheritable epigenetic change) in an egg-laying animal may have resulted in the first formation of blood platelets, approximately 220 million years ago.
In mammals and humans, platelets are responsible for blood clotting and wound healing, so play a significant role in our defense response. Unlike our other cells, they don't have nuclei—so are unique to mammals, since other classes of animal such as reptiles and birds have blood clotting cells with nuclei.
Our platelets are formed from megakaryocytes that mature in the bone marrow. When these megakaryocytes are released into the blood stream and reach the very high-pressure blood vessels the lungs, they "burst" apart, each cell releasing thousands of platelets inside the bloodstream.
The researchers suggest that millions of years ago a mammalian ancestor—possibly an animal related to the duck-billed platypus—underwent the very first formation of platelets, thanks to a sudden genetic change in the nucleus of its blood clotting cells that meant normal cell division did not take place causing the cells to increase in size.
If so, those much larger cells might then have been forced to burst inside the first capillaries they met in the animal's blood stream, releasing their cytoplasmic fragments. These fragments proved to be more efficient at stopping bleeding, so if this genetic change was inheritable, it would have given its offspring a major advantage through natural selection. An animal with this epigenetic change could stem bleeding from fighting or wounds much better than its competitors, and so live longer.
Professor Martin, Professor of Cardiovascular Medicine at UCL, says, "Because of the uniqueness of platelets, it is reasonable to suggest that a unique event led to their origin. This was a radical, internal evolution occurring in a single animal, on a single day, 220 million years ago, and was then reinforced by natural selection."
Professor Martin and his colleague Professor Paolo D'Avino (University of Cambridge) then suggest that this single cellular rapid change ultimately led to the development, over 120 million of years, to the placenta, allowing the fetus to be retained inside the mother for longer-term development and thus allowing evolution to achieve live birth. The ability to clot wounds is an essential element of live birth by means of a placenta, since the placenta splits from the mother's uterus during the birth process. The female would not survive birth and therefore not be able to suckle her offspring if she were unable to stem the bleeding.
In their paper, Professors Martin and D'Avino propose experiments that would support their hypothesis, including in vitro and in animal models.
"Without this single critical epigenetic change, we suggest mammals would never have evolved, and therefore human beings would not be around today," says Professor Martin. "With this research, we've laid down a marker based on the available evidence—and we're suggesting these experiments that will either support or help to refute our hypothesis."