Human Evolution

[Genady]

12 minutes ago, studiot said:

Taxon for instance seems to me to be akin to a set in maths and is a very general term.

Not so in biology: Taxon | biology | Britannica.

[studiot]

11 minutes ago, Genady said:

Not so in biology: Taxon | biology | Britannica.

 

Quote

Wikipedia

Taxon - Wikipedia

In biology, a taxon (back-formation from taxonomy; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular name and given a particular ranking, especially if and when it is accepted or becomes established. It is very common, however, for taxonomists to remain at odds over what belongs to a taxon and the criteria used for inclusion. If a taxon is given a formal scientific name, its use is then governed by one of the nomenclature codes specifying which scientific name is correct for a particular grouping.

This seems pretty general to me, allowing that biologists do not use the mathe specific term 'group'.

Basically it seems to say " A bunch of the things we are dealing with"

 

Why do you think it is not similar to a set in maths ?

Edited July 5, 2023 by studiot

[Genady]

2 minutes ago, studiot said:

 

This seems pretty general to me, allowing that biologists do not use the mathe specific term 'group'.

Basically it seems to say " A bunch of the things we are dealing with"

Taxons are specific. They are:

Quote

In the classification of protists, plants, and animals, certain taxonomic categories are universally recognized; in descending order, these are kingdom, phylum (in plants, division), class, order, family, genus, species, and subspecies, or race.

Biologists are not free to call any bunch of things a "taxon".

[dimreepr]

4 minutes ago, studiot said:

Why do you think it is not similar to a set in maths ?

Because maths actively work's toward a solution, life just works until it doesn't...

[Genady]

19 minutes ago, studiot said:

Why do you think it is not similar to a set in maths ?

Every taxon is a set of organisms, but not every set of organisms is a taxon.

[TheVat]

23 hours ago, swansont said:

Point to a living Homo erectus.

This is not a porn website, sorry.

[Peterkin]

8 minutes ago, TheVat said:

This is not a porn website, sorry.

Be consoled; there are many.

[CharonY]

Also, in the context of this discussion,  you wouldn't just use taxon, but name what level you're speaking of.  E.g. species x is extinct or genus y or family z.

There are also different types of taxonomic systems (basically different ways to build the family tree) and you would refer to which system you are talking about.

I.e. you define the sets you're speaking or you use the commonly accepted consensus. But you don't randomly fill it with a bunch of things.

[Bufofrog]

On 7/2/2023 at 6:37 PM, mistermack said:

Yes, wikipedia is capable of having one article contradict another. It's just the old problem of definition of words. 

wikipedia :  " Extinction is the termination of a taxon by the death of its last member." 

That obviously never happened with homo erectus.

Ironically enough, that obviously did happen.  Modern humans and Homo erectus were contemporaries.  Homo erectus and Homo sapiens lived as 2 separate species for at least 100,000 years.  The last Homo erectus died between 50 and 100 thousand years ago.

Edited July 5, 2023 by Bufofrog

[studiot]

4 hours ago, Genady said:

Every taxon is a set of organisms, but not every set of organisms is a taxon.

Since you chose to use ridicule in answer to an honest question but ignored the rest of my comments on definitions,

I take it you agree with the rest of those definitions ?

3 hours ago, TheVat said:

This is not a porn website, sorry.

LOL  +1

[Genady]

24 minutes ago, studiot said:

Since you chose to use ridicule in answer to an honest question but ignored the rest of my comments on definitions,

I take it you agree with the rest of those definitions ?

I am very sorry indeed. I didn't mean to use ridicule, and I am sorry that it came through as if I did. This is a difference between sets and taxa.

What other definitions?

I don't think the arguing in the thread was about definitions. It was about misapplying them.

Edited July 5, 2023 by Genady

[Genady]

1 hour ago, studiot said:

I take it you agree with the rest of those definitions ?

I don't see a disagreement about definitions in this thread. By any definition, in any classification scheme of organisms in biology, Homo sapiens and Homo erectus are two different species.

There is a finite number of animals, and they can be linearly arranged by the time of their death. Thus, by any definition, somewhere on this line there is a last Homo erectus. After that, the Homo erectus species is extinct.

[studiot]

1 hour ago, Genady said:

I am very sorry indeed. I didn't mean to use ridicule, and I am sorry that it came through as if I did. This is a difference between sets and taxa.

What other definitions?

I don't think the arguing in the thread was about definitions. It was about misapplying them.

 

In turn I am sorry if I was a bit harsh.

As regards mathematical set theory I only said biological taxons to be similar, I did not say they were the same.

The similarity I was meant refers to the idea that they are both head of a chain of 'trickle down' classifications.

As far as I can see your comment, though true, has nothing to do with this thread.

 

The main other definition I was referring to was about the use of the words extinct and extinguish in Science. 

 

Did you read the Wiki article I linked to ?

One important  point it made was that taxonomists themselves can't agree these classification schemes.

 

So perhaps you can explain why there are many 'extinct' volcanoes in our solar system, or what the'extinction coefficient in Physics, Optics  and Physical Chemistry means, following the 'definition' that has been laid down several times in this thread.

[Genady]

I see. I didn't refer to definitions of words, specifically, the word "extinct". I only referred to how it is used in biology, more specifically, in the study of biological evolution. I don't know, how its uses in other sciences relate to this one.

Regarding the different taxonomies, as I've described in my previous comment, any classification scheme leads to the same conclusion that the species Homo erectus is extinct. The difference is only in when exactly it happened.

Edited July 5, 2023 by Genady

[TheVat]

It was helpful when they added "the" or "truly" to the mnemonic, Dear King Phillip Came Over For Truly Good Soup .

The addition of tribe, e.g. Hominins, was helpful in understanding our lineage and how we are more closely related to chimps than orangs.

 

[Genady]

Sometimes there are also Suborders, Subfamilies, etc., e.g.,

Bonobo - Wikipedia

[studiot]

1 hour ago, Genady said:

I see. I didn't refer to definitions of words, specifically, the word "extinct". I only referred to how it is used in biology, more specifically, in the study of biological evolution. I don't know, how its uses in other sciences relate to this one.

I also think there is a link between the classification scheme and the definition of words, especially ones like extinguish or extinct.

But I think it is just more subtle, yet far reaching then MrMack said

[Genady]

2 minutes ago, studiot said:

I also think there is a link between the classification scheme and the definition of words, especially ones like extinguish or extinct.

But I think it is just more subtle, yet far reaching then MrMack said

How do you think such a link works in other languages? E.g., in Russian the word for biological extinction has nothing to do with the word for extinguishing. Same in Hebrew.

[studiot]

1 minute ago, Genady said:

How do you think such a link works in other languages? E.g., in Russian the word for biological extinction has nothing to do with the word for extinguishing. Same in Hebrew.

Quite frankly I don't know and I don't care.

The classification scheme is not in English, Russian or Hebrew, but is set by international agreement.

 

The point is that I could ask the same question in any language.

The classification scheme is a victim of its own rigidity.

I believe you correctly recently pointed out to someone that a woodlouse has too many legs to be an insect.

Now transfer that thinking to the classification of dogs.

Somewhere at the head of that classification scheme you will be told that a dog is a four legged animal with or without tail, hair  etc etc.

Somewhere near the bottom you will find different kinds of dog.

Choose one of the rare kinds with maybe 1000 examples throughout the world. Call it a bow-wow.

Now consider the following.

There exists a small percentage of dogs with only 3 or 2 legs.
Sometimes this is a result of accident, sometimes disease, some are just born that way.

In a small population like bow-wows a small incidence factor will lead to there sometimes being 2 legged bow-wows and sometimes not

So in the times when there are no 2 legged bow-wows are they extinct ?

We have already seen simplistic rigid definitions that would suggest this is the case.

 

 

 

[Genady]

10 minutes ago, studiot said:

Quite frankly I don't know and I don't care.

The classification scheme is not in English, Russian or Hebrew, but is set by international agreement.

 

The point is that I could ask the same question in any language.

The classification scheme is a victim of its own rigidity.

I believe you correctly recently pointed out to someone that a woodlouse has too many legs to be an insect.

Now transfer that thinking to the classification of dogs.

Somewhere at the head of that classification scheme you will be told that a dog is a four legged animal with or without tail, hair  etc etc.

Somewhere near the bottom you will find different kinds of dog.

Choose one of the rare kinds with maybe 1000 examples throughout the world. Call it a bow-wow.

Now consider the following.

There exists a small percentage of dogs with only 3 or 2 legs.
Sometimes this is a result of accident, sometimes disease, some are just born that way.

In a small population like bow-wows a small incidence factor will lead to there sometimes being 2 legged bow-wows and sometimes not

So in the times when there are no 2 legged bow-wows are they extinct ?

We have already seen simplistic rigid definitions that would suggest this is the case.

 

 

 

For such reasons, scientific classifications of organisms are not arbitrary, but are developed via many studies and research, discussions, consideration of variety of factors, adjustments, etc. They are also not rigid, but are adjusted when new results, factors, etc. are discovered.

In no scientific classification of dogs, for example, number of legs, tail, hair, etc. are found. Here it is:

Dog - Wikipedia

 

[studiot]

Your list is woefully short, anyone would think we had not proceeded down to the DNA level since linneaus in 1700.

eg

the stabyhoun is a dog

but it is picked out from other dogs by its genetics

(it is also rare about 4000 in the world)

But it is accepted as a separate category by the relevant authorities.

https://studenttheses.uu.nl/bitstream/handle/20.500.12932/21271/PDA_LMVlutters_definitief.pdf

[Genady]

1 minute ago, studiot said:

Your list is woefully short, anyone would think we had not proceeded down to the DNA level since linneaus in 1700.

eg

the stabyhoun is a dog

but it is picked out from other dogs by its genetics

(it is also rare about 4000 in the world)

But it is accepted as a separate category by the relevant authorities.

https://studenttheses.uu.nl/bitstream/handle/20.500.12932/21271/PDA_LMVlutters_definitief.pdf

But this category is not related to evolutionary biology. It rather seems medical. There are many other classifications, e.g., by breeders, by competitions. They are irrelevant in this thread.

[Ken Fabian]

With a Mistermackian classification scheme there is just one species - everything living is descended from it and by that definition is all the same species and it takes abiogenesis to have a different species. But I think it is arguing etymology -  what the word species means - rather than biology. For convenience we go with the usual definition - which isn't as clear cut as "can interbreed".

We have a lot of (unfortunately named) homo erectus DNA, that lives on in homo sapiens - we are indeed descendants - but sapiens has significant differences too, more than enough to rate being a separate species, the naming of which is to some extent a judgement call.

Actually would not surprise me if sapiens and erectus could interbreed - no living apes are nearly so closely related - and the successful variants on the road to a different species would have done so with gene flow as an evolutionary mechanism. Like wolves being able to breed with dogs it doesn't make them the same species.

Erectus had descendants that had significant differences and ultimately those survived whilst the descendants that stayed much the same did not. We are descendants but we are not homo erectus.

Edited July 6, 2023 by Ken Fabian

[Genady]

17 hours ago, studiot said:

The similarity I was meant refers to the idea that they are both head of a chain of 'trickle down' classifications.

A biological classification of a taxon does not put it at the head of a chain of 'trickle down' classifications, i.e., it does not aim to answer, what the taxon contains, but rather, where the taxon is in the "tree of life". 

Continuing with the dog example, the biological classification of the species, C. familiaris, does not have it on top, like this: 

14 hours ago, studiot said:

Somewhere at the head of that classification scheme you will be told that a dog is a four legged animal with or without tail, hair  etc etc.

Somewhere near the bottom you will find different kinds of dog.

but rather has it on the bottom, like this:

or like this:

and so on.

The difference is what is meant by "to classify" something: to "classify a set" is to analyze its contents, while to "classify a taxon" is to show its relations to other taxa.

Edited July 6, 2023 by Genady

[TheVat]

The cladistic approach makes a lot of things clearer, regarding species and extinction.

https://link.springer.com/article/10.1007/bf00144036

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

(from Springer article) The correct explanation of why species, in evolutionary theory, are individuals and not classes is the cladistic species concept. The cladistic species concept defines species as the group of organisms between two speciation events, or between one speciation event and one extinction event, or (for living species) that are descended from a speciation event. It is a theoretical concept, and therefore has the virtue of distinguishing clearly the theoretical nature of species from the practical criteria by which species may be recognized at any one time.