Is a human zygote a human (not person, cladistically human)

[Nesslig20]

I went on Steve McRae's hangout last day and I disagreed with Steve on wether a human zygote is a human.


I think a human zygote is a human by cladistic classification. Any organism that is descendant of a clade is a member of that clade. A human zygote is an organism that descended from the human clade "Hominina", therefore a human zygote is a member of that clade and thus a human.

My argument.

P1. If an organism descended from a member of homo, then the organism is a member of homo.
(cladistics)

P2. If an organism is a member of homo, then the organism is a human.
(which is the definition of human in biological classification)

P3. A human zygote is an organism
(basic biology)

P4. A human zygote descended from a member of homo
(basic biology)

C1. So, a human zygote is a human.

Keep in mind, I am not arguing over any philosophical or legal issue. It is merely biological classification, that's it. That's why this is under the topic "science".
Also drop the "being" qualifier. My argument only concludes it is a human. "Being" isn't a biological term, thus I didn't use it in my argument. If a human automatically means human being to you, fine. Then it is a human being according to you.
I am pro-choice so it isn't meant as an argument against abortion either. Als bear in mind that personhood isn't the same as human.

 

[Rumraket]

Re: Is a human zygote a human.

I agree it's human. Human corpses are also human, they're dead humans. There's really no need to deny something like this.

 

[Duvelthehobbit666]

Re: Is a human zygote a human.

To a certain extent yes. However, to play devil's advocate, how far along the evolutionary line do you need to go for something to be non-human if humans only can give birth to humans?

 

[Nesslig20]

Re: Is a human zygote a human.

To a certain extent yes. However, to play devil's advocate, how far along the evolutionary line do you need to go for something to be non-human if humans only can give birth to humans?

Never, it never ends. Cladistics and the law of monophyly demands that every organism would always be part of the ancestral clade it descended from and so will all its ancestors be.

Snakes descended from tetrapods, they still are tetrapods, even though they don't have any legs. This is one example of the law of monophyly.

A human zygote is an organism is still part of its ancestral clade "Hominina" from which it descended. Hominina is the scientific definition of the group or organisms, that includes humans (all and only humans)

 

[Grumpy Santa]

Re: Is a human zygote a human.

To a certain extent yes. However, to play devil's advocate, how far along the evolutionary line do you need to go for something to be non-human if humans only can give birth to humans?

Never, it never ends. Cladistics and the law of monophyly demands that every organism would always be part of the ancestral clade it descended from and so will all its ancestors be.

Snakes descended from tetrapods, they still are tetrapods, even though they don't have any legs. This is one example of the law of monophyly.

A human zygote is an organism is still part of its ancestral clade "Hominina" from which it descended. Hominina is the scientific definition of the group or organisms, that includes humans (all and only humans)

However a zygote doesn't possess any of the characteristics (yet) that would define it as human. Cladistically speaking I'd say no, a human zygote isn't a human yet.

Let's look at it this way... list the defining characteristics of Hominoidea. Does a zygote meet this set of definitions?

Just a quick Wiki look shows this...

Apes (Hominoidea) are a branch of Old World tailless anthropoid catarrhine primates native to Africa and Southeast Asia. They are distinguished from other primates by a wider degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.

Zygotes don't even have shoulder joints yet.

It's true that you "never stop being what you were" cladistically. A snake, as mentioned, is still a tetrapod. But the analogy is invalid. We're not talking about descent from earlier species, we're talking about a ball of cells yet to develop into the animal (in this case). While it's genetically a human, it isn't human yet.

 

[Dragan Glas]

Re: Is a human zygote a human.

Greetings,

Genetically it is.

Kindest regards,

James

 

[Nesslig20]

Re: Is a human zygote a human.

Never, it never ends. Cladistics and the law of monophyly demands that every organism would always be part of the ancestral clade it descended from and so will all its ancestors be.

Snakes descended from tetrapods, they still are tetrapods, even though they don't have any legs. This is one example of the law of monophyly.

A human zygote is an organism is still part of its ancestral clade "Hominina" from which it descended. Hominina is the scientific definition of the group or organisms, that includes humans (all and only humans)

However a zygote doesn't possess any of the characteristics (yet) that would define it as human. Cladistically speaking I'd say no, a human zygote isn't a human yet.

First bear in mind: I am NOT saying that a zygote is a human in any philosophical sense or anything that applies in the law. It is pure biology, saying that a human zygote is a human doesn't mean it has rights nor does it mean it is a person. Personhood is a matter of philosophy, but not biology. "Humanhood" is a biological thing. I am pro-choice so don't see this as an argument against abortion, and don't think that "admitting I am right" means anything on your stance on abortion, because it doesn't as explained.

Now to address your post.
I don't think you understand what cladistics is. Cladistics is the classification of organisms according to their ancestry (including the characteristics of their ancestors). I gave you the example of snakes. Snakes descended from tetrapods (four limbed vertebrates), but snakes usually (unless in atavism) never develops any limbs at all. But the ancestors of snakes did have these characteristics, thus the ancestors of snakes were tetrapods and by cladistics, this makes the snake is a tetrapods also, even though it doesn't have the four limbed trait that its ancestors had.

The same would apply to a zygote, it is an organism with hominina as its ancestral clade, thus it is part of that clade.

Let's look at it this way... list the defining characteristics of Hominoidea. Does a zygote meet this set of definitions?

Just a quick Wiki look shows this...

Apes (Hominoidea) are a branch of Old World tailless anthropoid catarrhine primates native to Africa and Southeast Asia. They are distinguished from other primates by a wider degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.

Zygotes don't even have shoulder joints yet.

By that definition this woud not be a hominoid aka ape:

(This human clearly has a wide degree of freedom of motion at the should joints to perform brachiation)

What you don't get is that this organism (despite being limbless) still is a tetrapod (four limbed vertebrate) because its ancestors were tetrapods. And it would also still be a hominoid because its ancestors were hominoids.

It's true that you "never stop being what you were" cladistically. A snake, as mentioned, is still a tetrapod. But the analogy is invalid. We're not talking about descent from earlier species, we're talking about a ball of cells yet to develop into the animal (in this case). While it's genetically a human, it isn't human yet.

We are talking about a descendant from an organism. A descendant also called an "offspring" is the resulting organism of the biological process of reproduction. Humans reproduce typically sexually and sexual reproduction is defined as the merging of two gamete (sperm and egg) cells to form a new organism, the zygote. When the zygote is formed, reproduction is finished and you have a new descendant organism, by definition.

It isn't even an analogy.
A snake is a tetrapods in the same sense a whale is a tetrapod, and in the same sense a human zygote is also a tetrapod.
None of them have four limbs, but they are organisms that descended from their ancestors who did have four limbs.

 

[Grumpy Santa]

Re: Is a human zygote a human.

First bear in mind: I am NOT saying that a zygote is a human in any philosophical sense or anything that applies in the law. It is pure biology, saying that a human zygote is a human doesn't mean it has rights nor does it mean it is a person. Personhood is a matter of philosophy, but not biology. "Humanhood" is a biological thing. I am pro-choice so don't see this as an argument against abortion, and don't think that "admitting I am right" means anything on your stance on abortion, because it doesn't as explained.

[/quote}

Never meant to imply you did.

Now to address your post.
I don't think you understand what cladistics is. Cladistics is the classification of organisms according to their ancestry (including the characteristics of their ancestors). I gave you the example of snakes. Snakes descended from tetrapods (four limbed vertebrates), but snakes usually (unless in atavism) never develops any limbs at all. But the ancestors of snakes did have these characteristics, thus the ancestors of snakes were tetrapods and by cladistics, this makes the snake is a tetrapods also, even though it doesn't have the four limbed trait that its ancestors had.

Actually I agree fully with this assessment.

The same would apply to a zygote, it is an organism with hominina as its ancestral clade, thus it is part of that clade.

Here's where I disagree, and I think it's better to say not from a cladistic perspective. It's a mass of human cells in the process of developing into a human, it's not a human as of yet. If all goes well it will be.

Is an egg a chicken (assume a chicken laid the egg)? At what point do you go from an egg to a chicken? You're implying when the egg is fertilized, I'm saying after the chick has developed enough to have the characteristics of a chicken and isn't simply a mass of dividing cells.

Let's look at it this way... list the defining characteristics of Hominoidea. Does a zygote meet this set of definitions?

Just a quick Wiki look shows this...

Apes (Hominoidea) are a branch of Old World tailless anthropoid catarrhine primates native to Africa and Southeast Asia. They are distinguished from other primates by a wider degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.

Zygotes don't even have shoulder joints yet.

By that definition this woud not be a hominoid aka ape:

(This human clearly has a wide degree of freedom of motion at the should joints to perform brachiation)

What you don't get is that this organism (despite being limbless) still is a tetrapod (four limbed vertebrate) because its ancestors were tetrapods. And it would also still be a hominoid because its ancestors were hominoids.

Why do you think I don't get this? By the way, by definition he would be an ape.

It's true that you "never stop being what you were" cladistically. A snake, as mentioned, is still a tetrapod. But the analogy is invalid. We're not talking about descent from earlier species, we're talking about a ball of cells yet to develop into the animal (in this case). While it's genetically a human, it isn't human yet.

We are talking about a descendant from an organism. A descendant also called an "offspring" is the resulting organism of the biological process of reproduction. Humans reproduce typically sexually and sexual reproduction is defined as the merging of two gamete (sperm and egg) cells to form a new organism, the zygote. When the zygote is formed, reproduction is finished and you have a new descendant organism, by definition.

It isn't even an analogy.
A snake is a tetrapods in the same sense a whale is a tetrapod, and in the same sense a human zygote is also a tetrapod.
None of them have four limbs, but they are organisms that descended from their ancestors who did have four limbs.

[/quote]

Well, stop talking about decent from an offspring then. I'm talking about development of the individual from fertilization to being recognizable as a member of a species. All you have with a zygote is a group of cells dividing rapidly, not even a blastocyst yet. Eventually the blastocyst will become an embryo, at this point I think you have the best argument for claiming it's now "human".

You asked "Is a human zygote a human". To this I answer "Not yet, but if all goes well, it will be."

 

[Nesslig20]

Re: Is a human zygote a human.

Never meant to imply you did.

I never meant to imply that I thought that you implied that I did.
It was merely a clarification.

Now to address your post.
I don't think you understand what cladistics is. Cladistics is the classification of organisms according to their ancestry (including the characteristics of their ancestors). I gave you the example of snakes. Snakes descended from tetrapods (four limbed vertebrates), but snakes usually (unless in atavism) never develops any limbs at all. But the ancestors of snakes did have these characteristics, thus the ancestors of snakes were tetrapods and by cladistics, this makes the snake is a tetrapods also, even though it doesn't have the four limbed trait that its ancestors had.

Actually I agree fully with this assessment.

I am going to hold you on this.

The same would apply to a zygote, it is an organism with hominina as its ancestral clade, thus it is part of that clade.

Here's where I disagree, and I think it's better to say not from a cladistic perspective. It's a mass of human cells in the process of developing into a human, it's not a human as of yet. If all goes well it will be.

But it already is a human, according to cladistics, which is what defines an organism as a human or as a tetrapod, which you previously agreed with. Cladistics, an organism that is descended from a clade is part of that clade. That defines what type the organism is, wether it is a tetrapod (like snakes) or a human.
The only reason why you don't want to say "from a cladistic perspective" is because that would demonstrate that the zygote is indeed a descendant of humans and thereby cladistics it would be a human.

Is an egg a chicken (assume a chicken laid the egg)? At what point do you go from an egg to a chicken? You're implying when the egg is fertilized, I'm saying after the chick has developed enough to have the characteristics of a chicken and isn't simply a mass of dividing cells.

When an egg is fertilized, any egg (egg cell to be more specific) it is a new organism. That is the very definition of sexual reproduction. A fertilized egg is an organism, so what is the clade it descended from?

By that definition this woud not be a hominoid aka ape:
(This human clearly has a wide degree of freedom of motion at the should joints to perform brachiation)
What you don't get is that this organism (despite being limbless) still is a tetrapod (four limbed vertebrate) because its ancestors were tetrapods. And it would also still be a hominoid because its ancestors were hominoids.

Why do you think I don't get this? By the way, by definition he would be an ape.

By your definition he would not since you said that:
"[an ape has] wider degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation."

This guy clearly doesn't brachiate. Also apes are tetrapods, four limbs, this guy doesn't have four limbs. Your definition doesn't use cladistics as I have pointed out.

We are talking about a descendant from an organism. A descendant also called an "offspring" is the resulting organism of the biological process of reproduction. Humans reproduce typically sexually and sexual reproduction is defined as the merging of two gamete (sperm and egg) cells to form a new organism, the zygote. When the zygote is formed, reproduction is finished and you have a new descendant organism, by definition.
It isn't even an analogy.
A snake is a tetrapods in the same sense a whale is a tetrapod, and in the same sense a human zygote is also a tetrapod.
None of them have four limbs, but they are organisms that descended from their ancestors who did have four limbs.

Well, stop talking about decent from an offspring then.

Correction, "Well, stop talking about descent from an ancestor" or "Well, stop talking about an offspring then", because that line doesn't make sense.

We cannot stop talking about an offspring/descendant from an ancestor since that is what a zygote is. Again read my line (colored green)

I'm talking about development of the individual from fertilization to being recognizable as a member of a species. All you have with a zygote is a group of cells dividing rapidly, not even a blastocyst yet. Eventually the blastocyst will become an embryo, at this point I think you have the best argument for claiming it's now "human".

What you fail to get is that it already is a recognizable member of the clade "hominina" (the human clade) since
1. it is an organism (in the same way a snake is an organism)
2. it is a descendant of a clade, the human clade (in the same way a snake is a descendant of the clade "tetrapoda")
By cladistics, that makes It a recognizable member of that clade.

 

[tuxbox]

Re: Is a human zygote a human.

What irritates me is this, here in the States, corporations get personhood status, while unborn babies get zero protections. That being said, I agree with Dragan, a zygote is genetically a human. A zygote has the same DNA as an adult human if given the opportunity to live.

 

[WarK]

Re: Is a human zygote a human.

Is a drop of human blood a human too?

 

[tuxbox]

Re: Is a human zygote a human.

Is a drop of human blood a human too?

Lmao, very good point, however, I would like to point out that a drop of blood will never have a heartbeat, and also, that I'm pro-choice.

My irritation is with the fact that corporations have more rights than the unborn.

 

[he_who_is_nobody]

Re: Is a human zygote a human.

Yes. of course the hman zygote is a human, as pointed out by Nesslig20. What else could it be?

I am pro-choice so it isn't meant as an argument against abortion either. Als bear in mind that personhood isn't the same as human.

Honestly, the whole G+ community is lousy when it comes to arguing for abortions. This personhood issue always seems to come up, but never the actual reason why abortion is legal in the States. People have a right to their own bodily autonomy and it is as simple as that.

Just a quick Wiki look shows this...

Apes (Hominoidea) are a branch of Old World tailless anthropoid catarrhine primates native to Africa and Southeast Asia. They are distinguished from other primates by a wider degree of freedom of motion at the shoulder joint as evolved by the influence of brachiation. There are two extant branches of the superfamily Hominoidea: the gibbons, or lesser apes; and the hominids, or great apes.

That definition is pretty inaccurate for apes. Besides the fact that humans are apes and we are found living on every continent besides Antarctica, there were lots of apes that lived in Europe during the Miocene and other Epochs. Beyond that, a lot of the ancient apes did not brachiate, but had shoulder joints much like the other monkeys. The defining character for an ape is the Y-5 cusps of the lower molars.

Just nit-picking.

 

[Nesslig20]

Re: Is a human zygote a human.

Is a drop of human blood a human too?

No, because a drop of blood isn't an organism.

A zygote is an organism and a human zygote is an organisms that is a descendant of the hominina clade.

 

[WarK]

Re: Is a human zygote a human.

Is a drop of human blood a human too?

No, because a drop of blood isn't an organism.

A zygote is an organism and a human zygote is an organisms that is a descendant of the hominina clade.

Is it really an organism, though? It's just a single cell, isn't it?

Anyway, this seems like hair splitting. A human zygote has two components. human and zygote. We know where it came from and what it could eventually become. It feels like a premise of an argument for or against choice, depending if you think it is or it isn't a human.

 

[WarK]

Re: Is a human zygote a human.

Is a drop of human blood a human too?

Lmao, very good point, however, I would like to point out that a drop of blood will never have a heartbeat, and also, that I'm pro-choice.

O rly? Have you seen The Thing?

 

[Nesslig20]

Re: Is a human zygote a human.

Is it really an organism, though? It's just a single cell, isn't it?

Right, bacteria are single cells too, and they are organisms. So being single cellular doesn't mean it isn't an organism.

To get a better idea why it is an organism:
Biological reproduction is summarily defined as an organism (or two) "the parent(s)" producing a new organism "the offspring", which is the descendant and the ancestors are the progenitors which performed reproduction to produce it.

Sexual reproduction is finished when two gamete cells fuse to form a zygote. When the zygote forms, reproduction ends and the result would be by definition a new organism, thus the zygote is an organism, the offspring of the ancestors.

Anyway, this seems like hair splitting. A human zygote has two components. human and zygote. We know where it came from and what it could eventually become. It feels like a premise of an argument for or against choice, depending if you think it is or it isn't a human.

Don't misunderstand, this is not an argument against abortion or choice. I have clarified this again and again here.

The argument that is applicable to abortion is personhood and it isn't synonymous with being a human in a biological sense. I would argue that if we have aliens or androids with the same mental capability as us, they would qualify as persons also, without being humans. But personhood is a matter of philosophy. Human is a matter of biology, which is my argument is all about.

 

[Dragan Glas]

Re: Is a human zygote a human.

Greetings,

Medically, personhood can only occur if the brain is sufficiently developed - in humans, the brain doesn't complete its neurological development until around twenty-four months after birth.

Terrible twos anyone?

Kindest regards,

James

 

[Visaki]

Re: Is a human zygote a human.

I'd say it is a human. In the same way I will still be a human when my corpse is starting find a equal temperature with it's surroundings.

 

[Deleted member 619]

Re: Is a human zygote a human.

Any organism species that is descendant of a clade is a member of that clade.

Didn't watch the video, but this is the source of your malfunction. The cladistics line is entirely specious (see what I did there?)

Cladistics doesn't deal with organism classification, but with population classification. Lest we forget, it's an evolutionary framework, and evolution is a population phenomenon. You always have to be really careful when you start thinking about any evolutionary principles in the context of individual organisms.

That said, it's human. 'Human what?' is up for debate. Whether it constitutes an organism is going to rely heavily on how you define life, and that#s problematic.

Anyhoo, just wanted to point out that the cladistics approach is entirely without merit in this context.