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Old 7th February 2018, 09:41 AM   #1
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What are implications of a creature cloning itself?

https://www.nytimes.com/2018/02/05/s...es-europe.html

Quote:
This Mutant Crayfish Clones Itself, and It’s Taking Over Europe
If a creature like the crayfish clones itself doesn't this make it susceptible to disease?

Just wondering what is the biological pros and cons of this?
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Old 7th February 2018, 09:42 AM   #2
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Implications? Other than annoying calls from sales departments, I don't see one.
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Old 7th February 2018, 09:45 AM   #3
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Being genetically identical would mean they are all vulnerable to the same disease, once that disease emerges. Cricket bat willows, for those interested, are genetically identical. A willow disease could wipe out the sport.
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Old 7th February 2018, 09:56 AM   #4
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They might secure a role in the new Star Wars - Return of the Clones.
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Old 7th February 2018, 10:12 AM   #5
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I'm surprised that the article never once mentions the scientific term parthenogenesis. "It clones itself!" is the easy audience shocker - but it's presented as if science doesn't already know about this happening in nature.

Originally Posted by Wikipedia
There are a number of documented species, specifically salamanders and geckos, that rely on obligate parthenogenesis as their major method of reproduction. As such, there are over 80 species of unisex reptiles (mostly lizards but including a single snake species), amphibians and fishes in nature for which males are no longer a part of the reproductive process...

https://en.wikipedia.org/wiki/Parthenogenesis
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Old 7th February 2018, 10:24 AM   #6
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Pinky And The Brain Plot # 51

https://io9.gizmodo.com/every-single...the-1778890186
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Old 8th February 2018, 09:54 AM   #7
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Originally Posted by Hans View Post
https://www.nytimes.com/2018/02/05/s...es-europe.html



If a creature like the crayfish clones itself doesn't this make it susceptible to disease?

Just wondering what is the biological pros and cons of this?
Yes. Potato famine anyone?
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Old 8th February 2018, 09:56 AM   #8
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Originally Posted by Elagabalus View Post
Yes. Potato famine anyone?
All the Irish are genetically identical?
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Old 8th February 2018, 10:00 AM   #9
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Originally Posted by Hans View Post
https://www.nytimes.com/2018/02/05/s...es-europe.html



If a creature like the crayfish clones itself doesn't this make it susceptible to disease?

Just wondering what is the biological pros and cons of this?
On the pro side, it seems to have led to great reproductive success for the crayfish. It may also be LESS susceptible to some diseases.
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Old 8th February 2018, 10:01 AM   #10
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Man a bunch of Crayfish that all look the same. Imagine the implications.

On a serious note if this is some sort of natural phenomenon there has to be some evolutionary advantage to it. Population growth worth the risk of low bio-diversity maybe?
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Old 8th February 2018, 10:04 AM   #11
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Originally Posted by Porpoise of Life View Post
All the Irish are genetically identical?

It explains a lot, doesn't it?
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Old 8th February 2018, 10:35 AM   #12
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Is it a new mutation, or is it a newly discover thing?
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Old 8th February 2018, 10:56 AM   #13
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Originally Posted by MikeG View Post
Being genetically identical would mean they are all vulnerable to the same disease, once that disease emerges. Cricket bat willows, for those interested, are genetically identical. A willow disease could wipe out the sport.
Could something like that be... induced?

Asking for a friend.


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Old 8th February 2018, 12:28 PM   #14
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Quote:
Is it a new mutation, or is it a newly discover thing?
New mutation they can trace to within 25 years of occurring and spreading like crazy......perhaps it could be called a "new thing"

Quote:
The marbled crayfish (Procambarus virginalis) was first spotted in aquariums in Germany in the 1990s. Now, DNA sequencing suggests that the species is probably the product of two distantly related members of a different crayfish species, a team reported on 5 February in Nature Ecology and Evolution1.


https://www.nature.com/articles/d41586-018-01624-y

yummy on the barbie

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Old 8th February 2018, 12:47 PM   #15
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Originally Posted by JoeMorgue View Post
Man a bunch of Crayfish that all look the same. Imagine the implications.

On a serious note if this is some sort of natural phenomenon there has to be some evolutionary advantage to it. Population growth worth the risk of low bio-diversity maybe?
It is actuallly sex that is usually considered more of an evolutionary mystery. To be evolutionarily advantageous, the advantages of sex need to be at least twice the disadvantage of only passing on half your genes to an offspring. That is a huge barrier to overcome. The most likely hypothesis, in my opinion, is that sexual recombination provides a large boost to resistance to parasitic infection. I don't remember who said this, but an apt description is changing the locks on your immune system every generation.

However if a mutation back toward parthenogenesis arises, and there are not a lot of parasites around trying to infect that population, the mutants will quickly out compete the original population.
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Old 8th February 2018, 07:26 PM   #16
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Another interesting issue is that parthenogenesis arises relatively often in completely separate lineages, but doesn't seem to last that long (that is, if you look at examples of it on the evolutionary tree, they are usually relatively isolated examples with close relatives all reproducing sexually). So we are left with the question of both why it arises and why it doesn't tend to last long enough for entire genera to emerge. Fizil mentions what I think is the strongest explanation: sexual reproduction gives an edge in the arms race with parasites.

But then we're left with the interesting puzzle of the bdelloid rotifers which have continued to reproduce through parthenogensis over evolutionary time and diverged into a diverse lineage with over 450 separate species:

https://en.wikipedia.org/wiki/Bdelloidea
Quote:
Bdelloids are of interest in the study of the evolution of sex because a male has never been observed,[19] and females reproduce exclusively by parthenogenesis, a form of asexual reproduction where embryos grow and develop without the need for fertilization; this is akin to the apomixis seen in some plants.[20] Each individual has paired gonads. Despite having been asexual for millions of years, they have diversified into more than 450 species and are fairly similar to other sexually reproducing rotifer species.
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Old 9th February 2018, 07:00 PM   #17
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I have a chicken that lays fertile eggs.

Apparently, if I bought an incubator, I could raise identical copies of this chicken. (This takes care because the eggs develop much slower than normal eggs)

I was assuming that there must be a rooster gaining access to my yard from time to time, but it turns out to be a thing that some chickens (and more commonly turkeys) can do.

(Note. You can tell that the egg is fertile, because the embryo is much larger than the miniscule spec that is in an unfertilized egg.)

Once I realised that it was happening, I was seriously weirded out by the concept.
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Old 13th February 2018, 08:48 AM   #18
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Amazon fish challenges mutation idea

Originally Posted by BBC News
Evolutionary theory suggests that species favouring asexual reproduction will rapidly become extinct, as their genomes accumulate deadly mutations over time.

But a study on an Amazon fish has cast doubt on the rapidity of this decline.

Despite thousands of years of asexual reproduction, the genomes of the Amazon molly fish are remarkably stable and the species has survived. Details of the work have been published in Nature Ecology and Evolution...

Prof Manfred Schartl, who is based at the University of Würzburg and is one of the lead authors of the study, said: "The theoretical predictions were that an asexual species would undergo genomic decay and accumulate many bad mutations and, being clonal, would not be able to rely on high genetic diversity to react to new parasites or other changes in the environment. "There were theoretical predictions that an asexual organism would demise after around 20,000 generations."...

The Amazon molly had been around for half a million generations - far in excess of what theory would suggest.

Not only that, but when the scientists looked for hallmarks of long-term genomic decay there were very few, as Prof Schartl explained: "What we found is that this fish had preserved its hybrid genome and what we know from plant or animal breeding is that when we try to make something better we breed a hybrid". And he thinks it's this 'hybrid vigour' that underpins the Amazon molly's tenacious survival. "What nature has done is create from the beginning a good hybrid, which then thrived."

"Of course it got mutations but what we feel has not been taken into consideration is that evolution will wipe out the deleterious mutations and only those that become better with good mutations will thrive."...
http://www.bbc.com/news/science-environment-43047122
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Old 16th February 2018, 08:32 AM   #19
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Originally Posted by Fizil View Post
It is actuallly sex that is usually considered more of an evolutionary mystery. To be evolutionarily advantageous, the advantages of sex need to be at least twice the disadvantage of only passing on half your genes to an offspring.
I don’t think more genes would be passed on in asexual reproduction. Assuming a stable population, on average 1 parent would have one offspring under asexual reproduction while in sexual reproduction 2 parents would have 2 offspring. Genes would be spread out among more offspring and the precise configuration would be lost but, at least on average, the number of genes passed on would not differ IMO.
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Old 16th February 2018, 08:57 AM   #20
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It is quite common for some insects to utilize both strategies.

When times are good, sexual reproduction is the norm. Since times are good, even "less fit" individuals can survive and reproduce, ensuring lots of genetic variation in the next generation. This is on top of the added variety due to recombination.
When things change and times turn bad, there is lots of variation available, of which some individuals will do well in the new harsher conditions.
During harsh conditions asexual reproduction becomes the norm. Mates are hard to find and asexual reproduction facilitates a rapid increase in the number of individuals suited to the new conditions, but at the expense of variation.
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Old 16th February 2018, 09:15 AM   #21
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Originally Posted by novaphile View Post
I have a chicken that lays fertile eggs.

Apparently, if I bought an incubator, I could raise identical copies of this chicken. (This takes care because the eggs develop much slower than normal eggs)

I was assuming that there must be a rooster gaining access to my yard from time to time, but it turns out to be a thing that some chickens (and more commonly turkeys) can do.

(Note. You can tell that the egg is fertile, because the embryo is much larger than the miniscule spec that is in an unfertilized egg.)

Once I realised that it was happening, I was seriously weirded out by the concept.
Hens lay about an egg a day, whether they are fertilized or not. If you have no, rooster the eggs will be infertile and unable to hatch. It is not really possible to tell by looking at a fresh egg weather it was fertilized or not, you have to incubate and see if it starts developing.
I've never heard of an unfertilized chicken egg hatching, I think it's impossible.
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Old 16th February 2018, 09:24 AM   #22
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Originally Posted by Cheetah View Post
Hens lay about an egg a day, whether they are fertilized or not. If you have no, rooster the eggs will be infertile and unable to hatch. It is not really possible to tell by looking at a fresh egg weather it was fertilized or not, you have to incubate and see if it starts developing.
I've never heard of an unfertilized chicken egg hatching, I think it's impossible.
I already posted this link in the thread but I'll do it again. You can read about bird parthenogenesis including chickens.

https://en.m.wikipedia.org/wiki/Parthenogenesis
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Old 16th February 2018, 09:41 AM   #23
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Thanks, I should have seen that.

From the article it sounds very rare though for an unfertilized bird egg to hath, how often does a healthy chick result?


Edit:
Very quick research. Seems about 12-15% of unfertilized eggs do develop an embryo, but this development stops when the eggs are incubated. Very few chicks hatch and if it does, it rarely survives a week. Record is 8 days.

It's a fluke, not a strategy in birds. Looks like parthenogenesis just refers to the ability of unfertilized chicken and turkey eggs to develop embryos, not that the embryos are viable.
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Old 16th February 2018, 06:16 PM   #24
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Originally Posted by lomiller View Post
I don’t think more genes would be passed on in asexual reproduction. Assuming a stable population, on average 1 parent would have one offspring under asexual reproduction while in sexual reproduction 2 parents would have 2 offspring. Genes would be spread out among more offspring and the precise configuration would be lost but, at least on average, the number of genes passed on would not differ IMO.
The choice is not between a population of asexually reproducing organisms and a population of sexually reproducing organisms. When a mutation occurs it occurs within an individual organism. The question is, how does that mutation affect that organism's fitness. Or, if we wish to be more precise, a mutation occurs to a gene and we can look at the average effect of that mutation on the gene's representation in the gene pool over evolutionary time.

So, an organism in a previously sexually reproducing population has a mutation that causes it to reproduce asexually. The mutated gene then has a 100% chance of being passed on to it's offspring, rather than a 50% chance. Is this particular organism likely to have fewer total offspring than would a similar organism that reproduces sexually? I don't see any reason to expect it to, for instance, lay fewer eggs.

If it lays the same number of eggs as a similar organism without this mutation, then the mutation will be represented in the next generation at a rate double that of the non-mutation. That sounds like selection to me.

The argument based on parasitism, for why, over time, those offspring will be outcompeted by the offspring of sexually reproducing individuals, makes sense to me, however.
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Old 16th February 2018, 07:37 PM   #25
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Originally Posted by Porpoise of Life View Post
All the Irish are genetically identical?
Everyone should dicks his own potatoes while juicing Piglet!!!
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Old 21st February 2018, 09:22 AM   #26
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Originally Posted by Roboramma View Post
I don't see any reason to expect it to, for instance, lay fewer eggs.

If it lays the same number of eggs as a similar organism without this mutation, then the mutation will be represented in the next generation at a rate double that of the non-mutation. That sounds like selection to me.
How many eggs that are produced doesn’t matter. What matters is how many of these survive to produce offspring of their own. In asexual reproduction you’d have twice and many individuals producing eggs therefor twice and many eggs produced and assuming population size is constrained by outside pressure like food/predation the survival rate for eggs would be cut in half.
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Old 21st February 2018, 09:53 AM   #27
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Originally Posted by lomiller View Post
How many eggs that are produced doesn’t matter. What matters is how many of these survive to produce offspring of their own. In asexual reproduction you’d have twice and many individuals producing eggs therefor twice and many eggs produced and assuming population size is constrained by outside pressure like food/predation the survival rate for eggs would be cut in half.
What matters is the representation of the gene under selection in future generations.
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Old 21st February 2018, 01:01 PM   #28
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Originally Posted by Roboramma View Post
What matters is the representation of the gene under selection in future generations.
Exactly, and asexual reproduction doesn’t change this because passing more genes to each descendant is offset by having fewer surviving descendants.

Again back to the example of a stable population:
Sexual reproduction - each parents average 2 surviving descendants each with 50% of it’s DNA
Asexual reproduction - each parent averages 1 surviving descendant with 100%.

The final representation within the population is the same it’s just spread out across more descendants.
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Old 22nd February 2018, 06:46 AM   #29
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Originally Posted by Fizil View Post
It is actuallly sex that is usually considered more of an evolutionary mystery. To be evolutionarily advantageous, the advantages of sex need to be at least twice the disadvantage of only passing on half your genes to an offspring. That is a huge barrier to overcome. The most likely hypothesis, in my opinion, is that sexual recombination provides a large boost to resistance to parasitic infection. I don't remember who said this, but an apt description is changing the locks on your immune system every generation.

However if a mutation back toward parthenogenesis arises, and there are not a lot of parasites around trying to infect that population, the mutants will quickly out compete the original population.
You are viewing it on an individual level, on a species level sex also speeds up evolution as you can have two advantageous traits with separate origins spread through a species. You have to think in terms of species and not individual.
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Old 22nd February 2018, 06:52 AM   #30
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Originally Posted by Roboramma View Post
The choice is not between a population of asexually reproducing organisms and a population of sexually reproducing organisms. When a mutation occurs it occurs within an individual organism. The question is, how does that mutation affect that organism's fitness. Or, if we wish to be more precise, a mutation occurs to a gene and we can look at the average effect of that mutation on the gene's representation in the gene pool over evolutionary time.

So, an organism in a previously sexually reproducing population has a mutation that causes it to reproduce asexually. The mutated gene then has a 100% chance of being passed on to it's offspring, rather than a 50% chance. Is this particular organism likely to have fewer total offspring than would a similar organism that reproduces sexually? I don't see any reason to expect it to, for instance, lay fewer eggs.

If it lays the same number of eggs as a similar organism without this mutation, then the mutation will be represented in the next generation at a rate double that of the non-mutation. That sounds like selection to me.

The argument based on parasitism, for why, over time, those offspring will be outcompeted by the offspring of sexually reproducing individuals, makes sense to me, however.
Fundamentally with asexual reproduction you have a identical population while with sexual reproduction you do not. So if this is subject to new stresses the sexually reproducing species can change far more rapidly to adapt to a new environment.

If becoming bigger is an advantage more large individuals will mate and the species will far more rapidly become larger if that is advantageous than an asexually reproducing species could.
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Old 22nd February 2018, 06:53 AM   #31
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Originally Posted by lomiller View Post
How many eggs that are produced doesn’t matter. What matters is how many of these survive to produce offspring of their own. In asexual reproduction you’d have twice and many individuals producing eggs therefor twice and many eggs produced and assuming population size is constrained by outside pressure like food/predation the survival rate for eggs would be cut in half.
Depends, only if you have two sexes. In hermaphroditic species you have the same potential either way.
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Old 22nd February 2018, 06:55 AM   #32
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Originally Posted by Roboramma View Post
What matters is the representation of the gene under selection in future generations.
Genes don't care, it is how the species can best compete in the environment.
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Old 22nd February 2018, 06:58 AM   #33
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Originally Posted by MikeG View Post
Being genetically identical would mean they are all vulnerable to the same disease, once that disease emerges. Cricket bat willows, for those interested, are genetically identical. A willow disease could wipe out the sport.
Bananas, too, I believe.
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Old 22nd February 2018, 07:49 AM   #34
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Originally Posted by zooterkin View Post
Bananas, too, I believe.
Somewhat. Of course it has already happened with Bananas. That is why the cavendish replaced the gros michel.

http://www.bbc.com/news/uk-england-35131751
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Old 23rd February 2018, 12:34 AM   #35
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Originally Posted by lomiller View Post
Exactly, and asexual reproduction doesn’t change this because passing more genes to each descendant is offset by having fewer surviving descendants.

Again back to the example of a stable population:
Sexual reproduction - each parents average 2 surviving descendants each with 50% of it’s DNA
Asexual reproduction - each parent averages 1 surviving descendant with 100%.

The final representation within the population is the same it’s just spread out across more descendants.
Does an asexually reproducing individual within a sexually reproducing population only average 1 surviving descendant (or say, 2 second generation descendants)? If so, why?
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Old 23rd February 2018, 12:35 AM   #36
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Originally Posted by ponderingturtle View Post
Fundamentally with asexual reproduction you have a identical population while with sexual reproduction you do not. So if this is subject to new stresses the sexually reproducing species can change far more rapidly to adapt to a new environment.

If becoming bigger is an advantage more large individuals will mate and the species will far more rapidly become larger if that is advantageous than an asexually reproducing species could.
I agree.
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Old 23rd February 2018, 12:36 AM   #37
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Originally Posted by ponderingturtle View Post
Genes don't care, it is how the species can best compete in the environment.
No, the genes are the unit of selection. If a gene is selected for, even if it somehow negatively affects the species as a whole, it will still increase it's representation in the population.
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Old 24th February 2018, 11:23 PM   #38
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Originally Posted by Cheetah View Post
Hens lay about an egg a day, whether they are fertilized or not. If you have no, rooster the eggs will be infertile and unable to hatch. It is not really possible to tell by looking at a fresh egg weather it was fertilized or not, you have to incubate and see if it starts developing.
I've never heard of an unfertilized chicken egg hatching, I think it's impossible.
Trust me, you can tell.

The embryo was the size of a baked bean. Rather than the tiny spec (about the size of a match head, that is normally present).

If you dig around you can find papers about it (not my chickens of course).
http://www.thepoultrysite.com/articl...nic-mortality/
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Old 26th February 2018, 07:37 AM   #39
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Originally Posted by Roboramma View Post
No, the genes are the unit of selection. If a gene is selected for, even if it somehow negatively affects the species as a whole, it will still increase it's representation in the population.
But saying a gene has a goal is still hugely anthropomorphizing it. Evolution selects for the short term advantage not the long term which is what you are saying. That is true but there is no will or intent involved.

This is what causes highly specialized organisms to evolve even though those are highly susceptible to environmental changes.

And genes are not the unit of selection, they are bundled together in individuals that are the unit of selection. Genes are the unit of inheritance.
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Last edited by ponderingturtle; 26th February 2018 at 07:39 AM.
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Old 26th February 2018, 07:40 AM   #40
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If one clone has sex with another clone (of itself) does that count as masturbation?
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