|
Register | Sign In |
|
QuickSearch
Thread ▼ Details |
|
|
Author | Topic: "Best" evidence for evolution. | |||||||||||||||||||||||||||||||||||||||
PaulK Member Posts: 17827 Joined: Member Rating: 2.3
|
quote: Mutations change the genome. By definition. That’s how they can produce traits outside the parameters set by the [previous] genome. As seen with the pocket mice and the Scottish Fold cat.
quote: It is funny how your idea of thinking seems to equate to mindlessly agreeing with you.
quote: We also have plenty of evidence that evolution is the explanation and that it can happen. All you have is faith in your own failed arguments.
quote: First, evolution has no specific targets. The changes that happen are those that happen. Second, millions if trials are available. Consider population sizes and timescales. Third culmulative selection is in play. Not only is it all but inevitable, the existence of intermediate forms is strong evidence of it. You say that it can’t happen, but offer no strong reasons to think so. The evidence strongly supports the idea that it did happen. Why should we prefer your opinions to the evidence?
|
|||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
Mutations usually change the sequence of a gene and only affect what that gene does. If they affect something structural like a HOX gene they rearrange the parts, they don't add anything new. If a mutation gives you a four chambred heart in a creature with three normal chambers it's going to be a useless addition, not a step to a new creature.
No, millions of trials are NOT available. That means millions of neutral changes that do nothing, plus a bunch of weird useless changes, including many lethal, and even if you get one that could lead to a useful new functioning organ you need millions more to add to it. YES I KNOW for pete's sake that evolution doesn't have an AIM, but the task here is to imagine how a mammalian part COULD HAVE evolved from a reptilian part. That's not too hard for your highly evolved homo sapien brain is it? Edited by Faith, : No reason given. Edited by Faith, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||
PaulK Member Posts: 17827 Joined: Member Rating: 2.3 |
quote: Mutations can also add genes - usually copies of existing genes, but not always. And let me remind you that what a gene does is encode the structure of a protein that may be used in many places and for many purposes. I will also add that the change from the mammalian to the reptilian ear is a change in the arrangement of parts - with changes to the shapes and sizes and uses of those parts.
quote: Or so you assume. I think that a little more argument is required. Although the ear would be better since we have more fossil evidence to identify the actual changes.
quote: Of course they are. Mutations are not rare, and the populations involved must add up to truly massive numbers.
quote: Why would we need to imagine it when we have evidence showing how it happened? You can start with this Evolution of mammalian auditory ossicles (Wikipedia)
The evolution of mammalian auditory ossicles was an evolutionary event in which bones in the jaw of reptiles were co-opted to form part of the hearing apparatus in mammals. The event is well-documented[1] and important[2][3] as a demonstration of transitional forms and exaptation, the re-purposing of existing structures during evolution.[4] Really FaIth, you should do the research instead of relying on forcefully presenting your own uninformed opinions and expecting agreement. And to continue on that way when you have been answered is nothing more than bullying. Edited by PaulK, : Fixed url tag
|
|||||||||||||||||||||||||||||||||||||||
Taq Member Posts: 10077 Joined: Member Rating: 5.1
|
Faith writes: The genome of any given creature has only the stuff that makes that creature and no others. Every creature is born with DNA not found in either parent due to germline mutations. This has been directly observed. For example, we have observed that humans are born with between 50 and 100 substitution mutations. So what stops this process? If each person is born with mutations, what would stop them from accumulating over many generations?
Mutations may change some of the particular expressions of some of its particular code, but it cannot do anything beyond the parameters set by the genome. If it changes expression, then it has gone beyond the parameters.
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
Two important points here:
1) Your complaint that evolution "hasn't been observed" is a straw man. Evolution is a slow process, claiming that it doesn't happen because the millions of years it took for humans and chimps to evolve from a common ancestor means modern scientists cannot "observe" it doesn't mean it didn't happen. As far as I'm aware, when Darwin and Wallace established evolution nobody had yet observed a new species evolving. Think of plate tectonics: you can't see new continents forming over a weekend! 2) Evolution of new species has been observed. Not in primates, obviously, but in flowers and worms and such. If there are more species of such things now than there were in the past either your deity miraculously created new species or they evolved naturally. Here are some examples; 1. A population of worms separated into two populations (one in a lab) diverged until they could no longer interbreed.
quote: 2. A new species of grass evolved that can tolerate soil contaminated with mine tailings.
quote: 3. Mice brought from Europe to Madeira islands diverge into new species.
quote: 4. Flowers introduced into a new environment produce new species.
quote: Here is an example of humans breeding new species.
quote:
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
quote:First, this is another example of the ignorance creationists have for science. While it is true that over time more complex organisms have evolved (it could hardly be otherwise considering that the first living organisms were necessarily small in volume and mass) evolution does NOT prescribe that life must evolve unidirectionally to greater size and complexity. Just consider the mammalian forms that went back into the oceans, with descendants having fewer limbs! Second, when you imply the "original Kinds" had a different chromosome count you are implying that modern forms of life have a different number of chromosomes than older forms! If that's not evolution, what is? Are you really saying the "original Kinds" had a different chromosome count?
|
|||||||||||||||||||||||||||||||||||||||
Meddle Member (Idle past 1298 days) Posts: 179 From: Scotland Joined:
|
My point is that if you sincerely try to think through the trial and error required to get from one type of heart to the one you think it evolved to, you will discover that it is simply impossible. Try it for the task of evolving the mammalian ear from the reptilian. Sincerely, I said. I am just trying to describe what is possible using my own understanding of biology. Is there any reason to think I’m being insincere in this?In the case of the heart we know a thickening of the ventricular wall will split it into two ventricles because that is what happens to our own heart during foetal development and results from how and when our genes are expressed. This change prevents oxygenated blood from the lungs mixing with deoxygenated blood returning from the rest of the body, which makes it more efficient, especially as we need a constant supply of oxygen as endotherms to maintain our internal body temperature. This is not as important for frogs and reptiles as they use the environment to control body temperature, but even a partial change in the shape of the ventricle wall, as in the 3.5 chambers mentioned by dwise1, will help to control the flow and reduce this mixing. As you mentioned, the formation of the ear is another example of this principle. During foetal development we see formation of the Meckel's cartilage. Most of this cartilage becomes absorbed into our lower jaw, but part of it splits off and migrates to form bones of the middle ear. Again this is controlled by expression of our genes, and some of the intermediary steps are reflected in some reptile fossils, so we know it is possible. The point is that changes is gene expression during development can affect an individuals physiology, which would be described as variation within the population, but over many generations and favourable selection this variation can come to dominate the population. So a 3-chamber heart can become 4-chambered, or to give another example, a reptiles jaw can become broader and the musculature of their intestine can be modified. This is why I tried the analogy of origami, but I’m guessing it wasn’t as helpful as I hoped. Such is the way with analogies.
|
|||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
Creationist ignorance is what says the fossil order is defined by increasing complexity? I'm sure I got MY "ignorance" from one of you people here. Where else would I get it?
|
|||||||||||||||||||||||||||||||||||||||
Faith  Suspended Member (Idle past 1471 days) Posts: 35298 From: Nevada, USA Joined: |
...
Edited by Faith, : No reason given.
|
|||||||||||||||||||||||||||||||||||||||
jar Member (Idle past 421 days) Posts: 34026 From: Texas!! Joined:
|
When life starts as single cell or less organisms there is initially only one direction it can go, towards increased complexity. But once there are more complex critters there are three directions, more complex, less complex and same complexity.
Basics Faith. Learn the basics you have been taught over the last nineteen years here at EvC.
|
|||||||||||||||||||||||||||||||||||||||
JonF Member (Idle past 195 days) Posts: 6174 Joined: |
Well, you make up a lot of what you write.
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
quote:Not sure what you mean by this. You say that mutations are changes but then you say they are not anything that changes! Are you perhaps saying that these are changes, changes great enough to produce different species but that isn't enough to provide evidence of evolution to you?
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
quote:But doesn't the location in the sedimentary layers determine that different fossils were laid down in different eras, sometimes millions or even billions of years apart?
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
quote:This is, of course, a statement that the "originals" evolved into the creatures now living. Unless you're saying that at some time in the far past ALL the life forms we see today and that we also have fossil evidence for in the past were ALL existing at the same time (except for your brown bear/polar bear variations and such).
|
|||||||||||||||||||||||||||||||||||||||
Sarah Bellum Member (Idle past 623 days) Posts: 826 Joined: |
quote:If your "microevolution" extends to things like whales descending from land creatures with limbs (vestigial leg bones) then it's something rather more than "micro" evolution, isn't it? By the way, how did all those fish that require salt water survive when the rain during the "Flood" reduced the salinity of the oceans (or if the rains were salty, how did the freshwater fish survive?)
|
|
|
Do Nothing Button
Copyright 2001-2023 by EvC Forum, All Rights Reserved
Version 4.2
Innovative software from Qwixotic © 2024