Does Regional Variability play a HUGE roll in evolutionary development?

[Miles]

Miles,
I just joined MFK yesterday so I am a bit new here. I really know nothing about stingrays, but I do know a bit about evolutionary biology and your post caught my attention for that reason.

I'm a little unsure what you meant by the following:
"It's also interesting conversation to think that all Motoros are different species (based on teeth, denticles, body shape, etc) but have actually evolved their patterns to best fit their ecosystem - ie: The common motoro pattern has the most benefit of all stingray patterns, so every species eventually will morph into a Motoro.."

I was wondering what you meant by that last line. I am not sure anybody that has commented so far really has a grasp on evolution, but evolutionary change occurs at the level of the species, not the individual... and it doesn't necessarily take millions or even a hundred thousand years. Evolution can occur in a matter of weeks. (Watch fruit flies in a jar in a college genetics lab.)

Mutations are the agents of evolutionary change. When a new mutation occurs that improves an individual's reproductive fitness, it becomes established in the population. New mutations (which are adaptive) can become established quickly depending on selective forces, but there is no set direction for evolution. That is why I'm a bit troubled by your statement regarding one pattern being the most beneficial and all the others will eventually become this. That is flawed logic and is evolutionarily deterministic.

Just remember, fitness (or being"most fit" or "fittest) has to do with selective forces working at the time that the individual carrying particular traits is in existence and those selective forces are always changing. Evolutionary processes have no set endpoint and "fittest" only applies to a present set of selective forces working on a particular individual.

First of all, Welcome to MFK..

Second, Awesome second post..

Can you elaborate more? I think the point I was trying to make is this;

The Motoro pattern is so dominant and widespread, that perhaps it has reasoning (selective forces?) for being the 'most fit' pattern.. no matter the subspecies? (ie: a Potamotrygon Leopoldi displays a Motoro type pattern because it is the most fit at that time due to selective forces, but when that individual is bred back with a Leopoldi displaying a classic Leopoldi pattern, it produces only classic Leopoldi offspring??.. )

Also.. what roll do you think seasonal flooding, shortened gestation periods, and live birth may play in the evolutionary and mutations in potamotrygon?

More, more, more..

 

[Hawkfish3.0]

OscarBowfin, I see your point here. The statement you made at the end is basically what I was trying to point out when I said that certain traits that used to be vital to an organisms survival (not in those exact words), give way to new traits that better suit the organism in it's current environment. Thus, many organisms are in a constant state of evolution.

As far as length of time for evolutionary changes to take place, this will depend on many factors, not least among them being the complexity of the organism or the environment in which the organism lives.

This is great! There are obviously many ways to look at this topic.

 

[tank125]

I know exactly what Bowfin means, it was the hardest point to drive home with Evolutionary Ecology class. It is the belief that the individual has control, which is not true, it is the species that changes over time via reproduction and mutation, only by mutation which either random or caused by environmental stimulants. One has to overlook what man has done to Canine familiararis which is selective breeding, not evolution.

It is imperative that OscarBowfin's point is understood because it is paramount to the understanding of evolution.

So is this discussion about what is the most primative ray?

 

[Hawkfish3.0]

I know exactly what Bowfin means, it was the hardest point to drive home with Evolutionary Ecology class. It is the belief that the individual has control, which is not true, it is the species that changes over time via reproduction and mutation, only by mutation which either random or caused by environmental stimulants. One has to overlook what man has done to Canine familiararis which is selective breeding, not evolution.

It is imperative that OscarBowfin's point is understood because it is paramount to the understanding of evolution.

So is this discussion about what is the most primative ray?

I understand the point completely and agree 100%.

This is simply a discussion about the regional characteristics of rays, how they vary from region to region. It's not really about which ray is the most primitive or which is the most highly evolved. It basically started with Miles pointing out some observations he had noticed in the variances of rays from different regions.

 

[tank125]

So maybe if we can get some definitive answers we can tell by looking at a ray, where its from and maybe even what water conditions are most suited? Sounds like a good idea.

 

[FOX-P2]

Amazonian Rays are a bit of an enigma.
This conversation is no good without knowing the Biological definition of a " species".
http://en.wikipedia.org/wiki/Species#Definitions_of_species may help a bit.

Speciation is a big subject with myriad factors and influences. I cannot write about all so please Wiki the following as a good start to adding to your confusion:

Allopatric speciation
Adaptive radiation
Sympatric speciation
Reproductive isolation by Habitat , Temporal isolation, Behavioral isolation, Mechanical isolation , pre or post mating.
Directional Genetic drift .
Mutation , Recombination and F2 fitness.
Directional, Stabilizing and Disruptive selection .
The Hardy-Weinberg principle for population genetics.
Homozygosity
Assortative mating,
Chromosomes, Genes, Alleles.
the Wahlund effect


I think this will lead the interested to become even more confused about Potamotrygon, everyone else will be asleep after a few minutes

 

[Hawkfish3.0]

Amazonian Rays are a bit of an enigma.
This conversation is no good without knowing the Biological definition of a " species".
http://en.wikipedia.org/wiki/Species#Definitions_of_species may help a bit.

Speciation is a big subject with myriad factors and influences. I cannot write about all so please Wiki the following as a good start to adding to your confusion:

Allopatric speciation
Adaptive radiation
Sympatric speciation
Reproductive isolation by Habitat , Temporal isolation, Behavioral isolation, Mechanical isolation , pre or post mating.
Directional Genetic drift .
Mutation , Recombination and F2 fitness.
Directional, Stabilizing and Disruptive selection .
The Hardy-Weinberg principle for population genetics.
Homozygosity
Assortative mating,
Chromosomes, Genes, Alleles.
the Wahlund effect


I think this will lead the interested to become even more confused about Potamotrygon, everyone else will be asleep after a few minutes

You're probably right! But, I'm a science geek, and I love this stuff!

 

[tank125]

You're probably right! But, I'm a science geek, and I love this stuff!

agreed! But, I got my B.S. 6 years ago, that stuff looks vaguely familiar at best, nostalgia wants me to re-visit it, but.....

 

[Nic]

miles great thread.... but on the tail of juruense or tigrinus etc... mine were in fast current and slow current tanks and only ever used the tail when they swan around like a lure to attract fish for food... on to the motoro being the dominant species i thought that was discussed before and somewhat proven??? might be thinking of something else though... as far as the white water meets blackwater constant ph swings think about the rainy season and when it floods the PH of the rivers is gonna change drastically i cant see the ph being 100% stable in any part of the river at any point of the year anyway though... i think rays are alot more hardy than we think when it comes to ph and all and the only problem is when they are freshly imported the stress from shipping... but a major swing i could see being detrimental at the same time.... as far as evolution of them we will probably never have a true answer on.... im looking forward to these theorys at the symposium

 

[Hawkfish3.0]

agreed! But, I got my B.S. 6 years ago, that stuff looks vaguely familiar at best, nostalgia wants me to re-visit it, but.....

Well, I hear ya. I graduated HS 14 years ago, and I finished my AA 4 years ago, and I'm going back to finish my BA this summer. It's not easy to get back into it, but I took some bio and organic chem classes last fall at the University of Iowa. It was a challenge to start, but I was able to get back into it ok. I just wish I would have committed to my education earlier in life.

To simply answer the question posed by the title of this thread, I would say... yes, absolutely. It's certainly not the only factor, but it is a major one.