Anonymous at Tue, 11 Jun 2024 04:28:13 UTC No. 16227942

>>16227676
In "Developmental Biology," the 11th edition by Gilbert and Barresi, at the beginning of chapter 7 on page 217 it says

"Fertilization is the process whereby the gametes--sperm and egg--fuse together to begin the creation of a new organism."

On page 248, the authors emphasize that fertilization is not an event, but a process:

"Fertilization is not a moment or an event, but a process of carefully orchestrated and coordinated events including the contact and fusion of gametes, the fusion of nuclei, and the activation of development."

So does life begin at fertilization? No, technically not, as fertilization itself is not an event. But the onset of fertilization marks the beginning of the development of an organism.

Anonymous at Tue, 11 Jun 2024 05:06:16 UTC No. 16227972

>>16227942
How is it not an event? When one sperm enters one egg, the event occurs. How could it be a process when from the moment a sperm fuses to an egg, the egg cannot fuse with any other sperm, and thus has begun the process. Beginning a process is an event.

Anonymous at Tue, 11 Jun 2024 19:04:29 UTC No. 16228863

>>16227972
Beginning a process is an event, but fertilization is a process, not an event. You can say that the beginning of fertilization is an event. That is definitely legitimate. But as the book explains, fertilization is a process, not an event.

Anonymous at Wed, 12 Jun 2024 01:54:40 UTC No. 16229592

>>16228863
So is human genetic code found in the zygote immediately after the process of fertilization has begun? or is it a gradual, developmental process?
When exactly does the code manifest?

Anonymous at Wed, 12 Jun 2024 02:22:16 UTC No. 16229616

>>16229592
I think you're hung up on this. Calling it "code" suggests that you're not really up to speed on the subject.

Anonymous at Wed, 12 Jun 2024 02:29:55 UTC No. 16229627

>>16229616
So what constitutes when exactly a human life begins?

Anonymous at Wed, 12 Jun 2024 02:34:45 UTC No. 16229635

>>16229616
Also you dodged the question. I asked a basic question as to what biology textbooks teach.
>Beginning a process is an event, but fertilization is a process
So an event happens, then, does life begin before or after the event? in other words, is not the fertilization process a part of life?

Anonymous at Wed, 12 Jun 2024 02:36:02 UTC No. 16229638

>>16229635
Does life began AT* the event or some, perhaps arbitrarily accrued, later point in time?

Anonymous at Wed, 12 Jun 2024 03:03:11 UTC No. 16229667

>>16229592
>So is human genetic code found in the zygote immediately after the process of fertilization has begun?
No. From, the same textbook, it is stated that while the details of fertilization vary from species to species, it generally consists of four major events:

1. Contact and recognition between sperm and egg.

2. Regulation of sperm entry into the egg.

3. Fusion of the genetic material of sperm and egg.

4. Activation of egg metabolism to start development

Given this, I guess we can say that life begins at least on the fourth major event, given that you need metabolism for an organism to exist. But deciding when life begins exactly appears to be problematic, because all of the characteristics that make an organism live do not appear all at once. Events 3 and 4 are separate events.

>>16229635
I am not>>16229616
>Also you dodged the question. I asked a basic question as to what biology textbooks teach.
That is true, I did not answer your question. Let me try to answer your question directly:

The book I cited is the most popular textbook used in colleges in developmental biology courses, and it says that fertilization starts the process of the development of an organism. Given that this is the standard textbook, it is probably true that all biology textbooks (at the very least, those up to date) teach that life begins around fertilization. Not once however is the word "conception" mentioned in the book. So it seems that the word "conception" is an outdated word in developmental biology.

Anonymous at Wed, 12 Jun 2024 03:24:46 UTC No. 16229688

>>16229667
Ok, thanks, I appreciate that detailed response.
I was looking up how much time it takes between event 1 and 4, is 24 hours about right?
>It takes about 24 hours for a sperm cell to fertilize an egg. When the sperm penetrates the egg, the surface of the egg changes so that no other sperm can enter.
But also this,
>At the moment of fertilization, the baby's genetic makeup is complete, including whether it's a boy or girl.
Does this corroborate what you are saying? Is the "moment of fertilization" they mentioned in reference to after event 1 or 4?

Anonymous at Wed, 12 Jun 2024 03:35:23 UTC No. 16229702

>>16229688
The "moment of fertilization" is of course mythical, but if we're talking about the genetic makeup of a fertilized egg being complete, that would refer to event 3, not 4, since that is the fusion of genetic material of the sperm and egg. Event 4 is the activation of the egg metabolism to start development, which would I think would be the beginning of a new organism,

Anonymous at Wed, 12 Jun 2024 03:56:52 UTC No. 16229745

>>16229688
Same anon as >>16229702

I have to state some disclaimers.

The first disclaimer is that I am no expert in developmental biology, and I only recently bought that developmental biology textbook to determine like you have asked, when life begins.

The second disclaimer is that the chapter on fertilization doesn't directly answer when life begins.

The third disclaimer is the Scott Gilbert himself, one of the two authors of the book I quoted from, has written an article found here on the subject that you should read:

https://onlinelibrary.wiley.com/doi/10.1002/ntls.20220041

And inside of it he says

"As an embryologist and the author of a major textbook in embryology, I know that I can say very few things with absolute certainty. However, one thing I can say with absolute and total certainty is this: There is no consensus among biologists as to when independent human life begins."

So you should consider reading his perspective before finally coming to a conclusion. My conclusion is that human life begins when egg metabolism begins, but apparently that is not a part of a scientific consensus.

Anonymous at Wed, 12 Jun 2024 04:46:01 UTC No. 16229812

>>16229745
>There is no consensus among biologists as to when independent human life begins
I figured as much. I guess you have to define life first (can science do that?) If you define human life, somehow, as a body in accordance with active genetic makeup or something, then life would begin at stage 4, I suppose, but that doesn't change much for those who already say life begins at conception it only makes it one day later.