It is a problem of semantics. Can a trait be both novel and a modification of a feature found in an ancestor? Yes. Is the evolution of the human brain a novel feature amongst mammals? Yes. Is the human brain a modified version of previously exiting brains found in ancestral mammals? Yes. It is both.
The difference is that creationists are looking for the evolution of "something completely different". While this could be considered a novel trait, it would seem that it would not qualify as a trait acquired through modification. Domesticated dogs have novel traits and are modified versions of their ancestors. However, creationists claim that they are not "something completely different". They are still dogs.
Creationists are expecting evolution to do something that it just doesn't do, nor does it need to produce "something completely different" in order to produce the biodiversity we see today.
I think the problem some of us have is the chimp to man evolution.
I do now think there are transitionals, tho within (the yet undefined) kinds. For Wolf to Dog (variation within a kind) there would have to be some transitional within that species. As well as all other evolved species.
The problem (for me and I think other Creationists) is that we are classified as apes. On the dog will be dogs thread, I can see the fox, cat, canine connection no matter what there clade is. It's pretty similiar it seems. The jump I can't make is chimp to man (or a common ancestor between the two).
I can see if cat, fox, dog, horse - wolf, dog are all closley related. And to pair them off into kinds wouldn't really matter. They are all animals after all. Yet I do think there are "kinds" somewhere in all of the species. Just where the line is I don't know.
I think it comes down to where we humans fit in this whole thing, that is the problem for Creationists.
Also, land to water mammals (and water to land) is a big jump to make for Creationists (myself included). The amount of changes involved. I'm not sure what the TOE teaches on such transitions or if the Theory states that happend or happens.
There probably is some genectic similarities with land and water mammals...and i'm not sure how i would classify water dwelling "kinds". Is there clades for water mammals?
I'll have to go look it up. It's probably catagorized differently.
You've brought up several points in your statement above that shows that you've got some interest and some, albeit partial, understanding of what the theory of evolution, is but you have a lot of misunderstandings too. Instead of looking up individual issues, why don't you start from scratch with a foundation book so that you get the basics, then move forward from there?
I'm sure there are plenty of people here that could help and recommend reading material.
Life, don't talk to me about life - Marvin the Paranoid Android
Taxonomy Taxonomy has a long history, with Aristotle giving the first detailed classification of living things. His classification of animals was:
Blooded (vertebrates) Viviparous quadrupeds (land mammals) Birds Oviparous quadrupeds (reptiles and amphibians) Fish Cetaceans (Aristotle did not realize their mammalian nature) Bloodless (invertebrates) Land arthropods (insects, arachnids, myriapods) Aquatic arthropods (mostly crustaceans) Shelled animals (shelled mollusks, echinoderms, etc.) Soft animals (cephalopods, etc.) Plant-animals (cnidarians, etc., which superficially resemble plants) However, he had made no effort to classify plants or fungi. Modern approaches to taxonomy, while obviously more diverse than in Aristotle's time, but can be lumped into three major schools: phenetic, phylogenetic (cladistic), and evolutionary.
So to stick with vertebrates for now, there are land mammals, birds, oviparous, fish and cetaceans.
The mammal kind, bird kind, oviparous kind, fish kind, cetaceans kind.
Do any of these kinds transition/evolve into the another? Or do they stay in that kind?
I know science doesn't use the word kind but it's easier for me to seperate them for now using that term. I'm just using it loosley for to make it easy to understand what I mean and where i'm coming from.
Do any of these kinds transition/evolve into the another? Or do they stay in that kind?
I'm trying to understand what you're trying to get at here but because it's based on a core misunderstanding of what evolution is and how it works it's a little tricky.... ;-)
Nothing evolves into another kind of anything. (If you mean can a dog turn into a fish). Each organism travels along its own route adapting to it's changing environment as best it can. It also happens over thousands, even millions, of years - which is a concept humans have great difficulty imagining.
Sometimes this results in similar solutions to common problems like flight or vision, so a bat looks a bit like a bird despite them being totally different 'kinds'.
(When I say organism, I'm simplifying - evolution happens to groups of animals - breeding populations, not individuals.)
Edited by Tangle, : No reason given.
Life, don't talk to me about life - Marvin the Paranoid Android
I'm being a little to general here. RAZD and I already broke down the clades from feline and canine.
I talking more land mammal to water. I'm sure there is no reptile to feline stuff like that.
So there's kingdom, phylum/division, class, order, family, genus, species.
Where does cladistics fit in here? I'm a little confused about that. It seems reptiles don't fall into clades.
So the felidae is the family?
From Wiki:
There are 41 known species of felids in the world today, which have all descended from the same ancestor.[1] This taxon originated in Asia and spread across continents by crossing land bridges.
I'm going to let RAZD field this one, he's can better follow up from his dog and cats examples.
But don't worry about being confused, these things took centuries to compile and unless you have a proper notion of the ToE it will take a while to get your head round it.
Unfortunately, you're starting in the middle, not the beginning. As well as trying to understand taxonomy, you'd do well to read a basic starter on evolution generally to put it in context.
Life, don't talk to me about life - Marvin the Paranoid Android
quote: Also, land to water mammals (and water to land) is a big jump to make for Creationists (myself included). The amount of changes involved. I'm not sure what the TOE teaches on such transitions or if the Theory states that happend or happens.
The Theory of Evolution only says that we all descended from common ancestors.
The changes in some land mammals evolving into sea animals are deducted from verifiable, empirical evidence. It didn't have to happen, but it did.
I think your main concern would be humans. Something about humans being mammals. Just like all the other mammals. Maybe that is something you don't want to accept, because you want to believe that you are special?
A clade[note 1] is a group consisting of a species (extinct or extant) and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life".[1] The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological classification. In cladistics (which takes its name from the term), clades are the only acceptable units.
Maybe that is something you don't want to accept, because you want to believe that you are special?
I'm trying to keep beliefs out of it, sorry Pressie. I'm interested in the Science of it right now and classification and how and why classify the way we do and how I can possibly come up with a definition of "kinds" that can be worked into a scientific hypothesis for Creation. Maybe there is a thread for what you're asking. This thread isn't it.
I'm not like Tangle, I'm happy to stick my oar in uninvited.
A clade is a different type of division than species, family or genus. A clade refers to a particular species and all of its descendants. So a clade could be at any level of the Kingdom to Family spectrum provided all the members shared a common ancestral species. The more equivalent term would be taxon since that can also refer to groupings at many different levels. The difference between clades and taxons is that taxon is a more flexible term and can accommodate groupings on bases other than the common phylogenetic ones.
So in the case of the Felidae they represent a clade because they "have all descended from the same ancestor." Every single one of the levels in that scientific classification you posted from Wikipedia might represent a clade.
so to address the specific question ...
Is Felidae a clade or a family?
The answer is that it is both.
TTFN,
WK
P.S. I see that you have resolved this yourself, but I'll post it anyway since I went to the bother of typing it out.
Thanks. So which is a more "tighter" grouping in your opinion?
Cladistics seems easier to navigate but not as "classified" as (taxon?)taxonomy is.
If you were trying to break the species down to the finest details which would you choose? Or can it be a combination of the two systems? A new system so to speak using the two together?
Do any of these kinds transition/evolve into the another? Or do they stay in that kind?
Maybe an analogy will help:
Imagine that you were a black Irish American. You would be African because your great great great great grandfather was born in Africa. You would be Irish because your great grandfather was born in Ireland. You would be American because your father was born in America.
So - you (as an individual) would always be African, Irish AND American. In the same way an individual dog will always be a mammal, a canine AND a dog.
You are not able to change your heritage - e.g. you could not become a black Dutch American. And an individual dog could not change to being a fish instead of a mammal.
Over the generations, your great grandchildren could change their nationality though: e.g. their parents could move to Canada. But then they would be black Irish American Canadians. They couldn't alter their heritage.
And if, over the generations, 'mammal canine dog' evolved sonar they would not become bats. They would become 'mammal canine dog sonar'. They couldn't alter their heritage.
Edited by Panda, : No reason given.
Tradition and heritage are all dead people's baggage. Stop carrying it!
Thanks. So which is a more "tighter" grouping in your opinion?
As far as I'm aware, clades can be as 'tight' as you want: I suppose my parents, my siblings, and me could be classed as a clade, if anyone had reason to do so.
Clades and Linneaen classification are sometimes at odds, we could not class 'reptiles' as a clade, since it does not include all the descendants: it excludes birds and mammals.
quote:By the 21st century, most vertebrate paleontologists had adopted phylogenetic taxonomy, in which all groups are defined in such a way as to be monophyletic; that is, groups include all descendants of a particular ancestor. The reptiles as historically defined would be paraphyletic, since they exclude both birds and mammals, although these also evolved from the original reptiles. Colin Tudge wrote:
quote: Mammals are a clade, and therefore the cladists are happy to acknowledge the traditional taxon Mammalia; and birds, too, are a clade, universally ascribed to the formal taxon Aves. Mammalia and Aves are, in fact, subclades within the grand clade of the Amniota. But the traditional class Reptilia is not a clade. It is just a section of the clade Amniota: the section that is left after the Mammalia and Aves have been hived off. It cannot be defined by synapomorphies, as is the proper way. It is instead defined by a combination of the features it has and the features it lacks: reptiles are the amniotes that lack fur or feathers. At best, the cladists suggest, we could say that the traditional Reptilia are 'non-avian, non-mammalian amniotes'.
Cladistics seems easier to navigate but not as "classified" as (taxon?)taxonomy is.
'Clade' has a particular meaning whereas 'family', 'kingdom' etc, in the Linnaean system are somewhat subjective. Nevertheless, the old system managed to identify many clades.
quote:The idea of a "clade" did not exist in pre-Darwinian Linnaean taxonomy, which was based by necessity only on internal or external morphological similarities between organisms — although as it happens, many of the better known animal groups in Linnaeus' original Systema Naturae (notably among the vertebrate groups) do represent clades.
This is actually evidence of evolution. That one doesn't need to believe evolution in order to construct what is essentially a family tree construct regarding life on earth and for it to agree with other methods of constructing family trees (eg., DNA comparisons).
And this is why it is difficult to talk about 'novel' features evolving. Most truly novel features, evolved in very early life. After than, much evolution has been modification of existing features for novel uses. Jaws becoming ear structures, arms becoming wings that sort of thing. Descent with modification makes it difficult to point to an organism and declare 'There is a novel trait!'. Any truly novel trait will likely be small or lethal. In large or complex organisms it is difficult to detect small novel traits like this.
If you were trying to break the species down to the finest details which would you choose? Or can it be a combination of the two systems? A new system so to speak using the two together?
I'm guessing that some of this depends on the species in question and your motivations for 'breaking it down'. For instance, (and I'm just thinking off the top of my head here, so this might not be right) if you were examining a deme (basically: an isolated subset population of a species that breeds only within itself), you might not want to speak of clades since the deme might not be a clade. Though I suppose there may well be clades within the deme.
I don't think I can imagine a combination of two classification systems not creating more problems than it attempts to solve. I'd say your best bet is to use the system that suits your purposes. In evolutionary biology, this is often going to be clades, I'd wager.
It is a problem of semantics. Can a trait be both novel and a modification of a feature found in an ancestor? Yes. Is the evolution of the human brain a novel feature amongst mammals? Yes. Is the human brain a modified version of previously exiting brains found in ancestral mammals? Yes. It is both.
Indeed. The trait can be inherited and augmented to a level not previously seen, like the human brain (although we can argue that we are not alone in this).
The extra folds in the cerebral cortex enhance our thinking ability.
quote: ... Instead of being smooth and nearly featureless like a kidney or spleen, the cerebral cortex (the thin layer of gray matter forming the outer surface of the brain) is chock-full of wrinkles and folds. ... ... Sulci and gyri are simply a way of increasing the surface area of the cerebral cortex (and therefore the number of neurons) without greatly expanding the size of the skull....
Chimps also have convoluted brains, but not as much surface area, especially in the prefrontal cortex, so it is more a matter of degree than a different kind of brain.
The commonality of the brain and the convolutions are homologies, while the extent of development are derived.
The difference is that creationists are looking for the evolution of "something completely different". While this could be considered a novel trait, it would seem that it would not qualify as a trait acquired through modification. Domesticated dogs have novel traits and are modified versions of their ancestors. However, creationists claim that they are not "something completely different". They are still dogs.
Agreed, and further they claim that dogs will always be dogs (just as evolution says any offspring of dogs will always be members of the dog clade).
Creationists are expecting evolution to do something that it just doesn't do, nor does it need to produce "something completely different" in order to produce the biodiversity we see today.
And yet they seem unable to define what they actually mean by "something completely different" as a criteria to apply to evolved species.
Is a web-footed breed of dog "something completely different" ? Or are we talking about Monty Python searching for the lost grail?
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