How do opossums fit into evolution?

[good brother]

Opossums who ran away from predators were eaten at a higher rate than those who froze. This lead to the "freezers" leaving more offspring in the next generation.

Thank you for your response but it did not address the part I had bolded originally. I think that part is a very important subject to address.

So I am going to ask a follow up question to the OP (and I can because I posted the OP), How could opossums have evolved such a trait? I read on one fact page (Opossum Facts) about opossums that they don't actually play dead, they are frightened into an involuntary shock like state. This would make it a non-learned behavior. How would an involuntary, non-learned action mimicking dead things ever "evolve" into a living animal's defense mechanism reptertoire?

In Christ, GB

 

[Split Rock]

How would an involuntary, non-learned action mimicking dead things ever "evolve" into a living animal's defense mechanism reptertoire?

If the trait is genetically determined and provides an adaptive advantage, it will be selected for and increase in a population. Those with the trait survive to produce offspring, and the offspring inherit the trait. Those without the trait have lower fitness and produce fewer offspring. Eventually the population becomes dominated by those with the trait. This mechanism is called Natural Selection.

 

[good brother]

If the trait is genetically determined and provides an adaptive advantage, it will be selected for and increase in a population. Those with the trait survive to produce offspring, and the offspring inherit the trait. Those without the trait have lower fitness and produce fewer offspring. Eventually the population becomes dominated by those with the trait. This mechanism is called Natural Selection.

But how would that trait first appear? What would cause that trait to make itself manifest in an animal? How could such an involuntary, non-learned behavior become part of even the first opossum's defense mechanism repertoire?


In Christ, GB

 

[KimberlyAA]

That's because it does not fit into it.

Only eight years after Columbus first set foot on American soil, an opossum entered the pages of recorded history. A Southern opossum from Brazil was the first marsupial to be brought to Europe. The explorer Vincente Pinzón presented her to King Ferdinand and Queen Isabella of Spain in 1500, and showed them the opossum’s young in her pouch. The monarchs called the opossum an “incredible mother”.2

Here in my country we call the opposum "manicou".

 

[Loudmouth]

Thank you for your response but it did not address the part I had bolded originally. I think that part is a very important subject to address.



In Christ, GB

DNA changes result in instinctual changes which are then selected for. In this case, the instinct to "play dead" when threatened was selected for because those with that DNA change had more offpsring than those who did not.

 

[Loudmouth]

But how would that trait first appear?

How any inheritable trait first appear which is through a DNA mutation.

 

[NailsII]

The ever loveable, ever cute opossums would seem to present a mystery to evolution. Why and how would such a creature ever evolve the characteristic "playing opossum"? To stop mid chase and fall into a catatonic state seems to be a pretty lousy "defense mechanism". To a hungry predatory animal this would be fast food turned into sit down dining.

It only appears to be a mystery to those who don't understand evolution....

I know what you mean! Except for one thing. My dog is totally opportunistic. He used to drag over the "leftovers" of my neighbor's deer kills. It wasn't uncommon to have guts and bones strewn all over my yard. I'm sure that my other neighbors had suspicions!

You are aware that opossums stink, and when they play dead they really stink.
This alone is enough to put off their natural predators it would seem.
Whether or not an introduced species would fall for the ploy is basically irrelevant.

There are many species that "Freeze" rather than run. And more that use a combination of freezing to analyze the situation, then deciding to run at the most opportune time.

Indeed.
Most animals have visual fields that are much more sensative to movement, so freezing is actually a very good strategy.
Then you have the option to run away if you are spotted.

Therer are many animals that just freeze, such as hedgehogs - and again this doesn't work with cars.

You're right. They are still around and are still thriving. If this wasn't an advantageous adaptation, it would have drove them to extinction.

I think this is the first time I have seen you agree with an evolutinary standpoint.

How would an involuntary, non-learned action mimicking dead things ever "evolve" into a living animal's defense mechanism reptertoire?

Without being an expert in this area, I cannot be specific.
But as long as the trait worked (ie increased reproduction rates) then the mechanism is nowhere near as relevant as the response or outcome.

 

[good brother]

DNA changes result in instinctual changes which are then selected for. In this case, the instinct to "play dead" when threatened was selected for because those with that DNA change had more offpsring than those who did not.

How any inheritable trait first appear which is through a DNA mutation.

But many times when a mutation occurrs, the DNA will repair itself in subsequent generations. The DNA just doesn't mutate and stay mutated. It has it's own little back ups and safeguards to make sure that doesn't happen continually. That is built into it! So how would that happen and why wouldn't it just repair itself in future generations as it is designed to do?


In Christ, GB

 

[LifeToTheFullest!]

But many times when a mutation occurrs, the DNA will repair itself in subsequent generations. The DNA just doesn't mutate and stay mutated. It has it's own little back ups and safeguards to make sure that doesn't happen continually. That is built into it! So how would that happen and why wouldn't it just repair itself in future generations as it is designed to do?


In Christ, GB

Magic?

 

[Lion Hearted Man]

But many times when a mutation occurrs, the DNA will repair itself in subsequent generations. The DNA just doesn't mutate and stay mutated. It has it's own little back ups and safeguards to make sure that doesn't happen continually. That is built into it! So how would that happen and why wouldn't it just repair itself in future generations as it is designed to do?


In Christ, GB

Sorry pal but you don't seem to know much about genetics. Each human being you see on the street has 100-200 unique mutations in their DNA (you do too!) If there were no mutations or recombination events, there would be no variation in nature.

Point #1 of evolution: populations have varieties with different traits (mechanism: DNA mutations). Point #2: if one of these traits somehow confers a reproductive advantage, it ends up dominating the population (mechanism: natural selection).

 

[Loudmouth]

But many times when a mutation occurrs, the DNA will repair itself in subsequent generations.

That's not true at all. Reverse mutations are rare and not the norm. The observed mutation rate is about 100 per person for a 6 billion base diploid genome. The raw chances of any single mutation occuring at a specific base is 100 in 6 billion or 1 in 60 million. Therefore, the chances are much higher that future mutations will occur at other bases and not the one that was just mutated.

The DNA just doesn't mutate and stay mutated.

Yeah, it does.

It has it's own little back ups and safeguards to make sure that doesn't happen continually.

It only needs to occur once, in either the egg or sperm that makes that offspring. When you start with a single cell there is no back up. It is what it is. That organism starts with the mutations in that egg and sperm.

 

[good brother]

Sorry pal but you don't seem to know much about genetics. Each human being you see on the street has 100-200 unique mutations in their DNA (you do too!) If there were no mutations or recombination events, there would be no variation in nature.

Point #1 of evolution: populations have varieties with different traits (mechanism: DNA mutations). Point #2: if one of these traits somehow confers a reproductive advantage, it ends up dominating the population (mechanism: natural selection).

Are you saying that there are no mechanisms that are involved in anything that might be known as DNA repair?

Here, I'll give you a Wiki article since I know how popular some think it to be:

"DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many as 1 million individual molecular lesions per cell per day.[1] Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions induce potentially harmful mutations in the cell's genome, which affect the survival of its daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. When normal repair processes fail, and when cellular apoptosis does not occur, irreparable DNA damage may occur, including double-strand breaks and DNA crosslinkages.[2][3]
The rate of DNA repair is dependent on many factors, including the cell type, the age of the cell, and the extracellular environment. A cell that has accumulated a large amount of DNA damage, or one that no longer effectively repairs damage incurred to its DNA, can enter one of three possible states:

1. an irreversible state of dormancy, known as senescence
2. cell suicide, also known as apoptosis or programmed cell death
3. unregulated cell division, which can lead to the formation of a tumor that is cancerous

The DNA repair ability of a cell is vital to the integrity of its genome and thus to its normal functioning and that of the organism."
​

It appears that there is a great number of safeguards designed into DNA to keep mutations from just going buck wild on a cell. Why is it that evolutionists pay no attention to DNA repair? I suppose that's a whole other thread though.

In Christ, GB

 

[Lion Hearted Man]

Are you saying that there are no mechanisms that are involved in anything that might be known as DNA repair?

Did I say that? No. I have a degree in molecular biology, you think I would graduate without knowing about DNA repair enzymes?

DNA repair cannot stop every mutation. If that were so, there'd be no such thing as cancer.

 

[Loudmouth]

Are you saying that there are no mechanisms that are involved in anything that might be known as DNA repair?

We are saying that these DNA repair mechanisms do not fix all of the mutations, and they have no way of going back to the last generation to fix mutations in offspring. We OBSERVE that children have mutations not found in their parents. This is true in all species.

Why is it that evolutionists pay no attention to DNA repair?

Why is it that creationists ignore the mutations that DNA repair mechanisms miss?

 

[TerranceL]

This strategy works very well with many predators but is spectacularly unsuccessful with automobiles.

Hahaha, oh man my sides...

 

[sfs]

Are you saying that there are no mechanisms that are involved in anything that might be known as DNA repair?

You were talking about mutations being repaired in subsequent generations. That is not something that happens with known DNA repair mechanisms. DNA repair mechanisms repair mutations as they happen -- most of the time. The ones that don't are the mutations we see. And if the mutation is in a germ cell, then it will be seen in the next generation.

It appears that there is a great number of safeguards designed into DNA to keep mutations from just going buck wild on a cell. Why is it that evolutionists pay no attention to DNA repair?

Please, don't embarrass yourself. We (meaning biologists and geneticists) are well aware of DNA repair. (Who do you think discovered it?) It's a trivial fact that each generation has new mutations.

 

[good brother]

It only needs to occur once, in either the egg or sperm that makes that offspring. When you start with a single cell there is no back up. It is what it is. That organism starts with the mutations in that egg and sperm.

We are saying that these DNA repair mechanisms do not fix all of the mutations, and they have no way of going back to the last generation to fix mutations in offspring. We OBSERVE that children have mutations not found in their parents. This is true in all species.

In response to these two posts:

Have you ever seen the show on TLC called "Little People Big World"? It was about a husband and wife who are little people and it followed their daily lives and their family. They have two boys and one girl. One of the boys and the girl are "normal" size and the other boy is a little person. Now, even though both the parents have a mutation in their genes to make them be little people, that genetic trait was not passed on to two thirds of their offspring. So in response to your first post, even though both parents had that mutation to make them short, that did not pass on to but one of their offspring. In response to your second post, we find the children do NOT have the same mutation their parents had. An interesting fact aired once a week for several seasons.


In Christ, Gb

 

[sfs]

Have you ever seen the show on TLC called "Little People Big World"? It was about a husband and wife who are little people and it followed their daily lives and their family. They have two boys and one girl. One of the boys and the girl are "normal" size and the other boy is a little person. Now, even though both the parents have a mutation in their genes to make them be little people, that genetic trait was not passed on to two thirds of their offspring. So in response to your first post, even though both parents had that mutation to make them short, that did not pass on to but one of their offspring. In response to your second post, we find the children do NOT have the same mutation their parents had. An interesting fact aired once a week for several seasons.

That situation says nothing about mutations being repaired in subsequent generations. All it shows is that each parent has two copies of the relevant gene, and that they each have one short-stature copy and one normal-stature one(*), and that their form of dwarfism is dominant(**). Having a single mutant copy makes you short, but you still have a wild-type copy which you can pass on to your kids. In this situation, some children will have two normal copies, and have normal stature, while most will have one or more variant copies and have short stature(***).

(*) There are more complicated possibilities involving multiple genes, but the basic idea is the same.
(**) Achondroplasia, the most common type of dwarfism in humans, is dominant.
(***) In the case of achondroplasia, the children with two mutant copies die before or shortly after birth. So there is a good chance this couple has lost children.

 

[Jamin4422]

But many times when a mutation occurrs, the DNA will repair itself in subsequent generations.

An enzyme, DNA polymerase, moves along the DNA strands to start copying the code from each strand of DNA. This process has an error rate of about one in 100,000: rather high. When an error occurs, though, DNA polymerase senses the irregularity as a distortion of the new DNA’s structure, and stops what it is doing. How a protein can sense this is not clear.

Other molecules then come to fix the mistake, removing the mistaken nucleotide base and replacing it with the correct one. After correction, the polymerase proceeds. This correction mechanism increases the accuracy 100 to 1000 times.

DNA Proofreading, Cells Edit DNA Errors | Jon Lieff M.D.

 

[Lion Hearted Man]

Is it just me, or is good brother Gish Galloping all over the place?