Experiment Advice Needed!

  • We are currently upgrading MFK. thanks! -neo
sostoudt
Thank you for bringing that up. That concept you described was one of the key misconceptions I had when starting to study biology. It took a CSU professor to finally explain to me the difference between what I believed to be true: Inheritance of acquired characteristics (or similar to Lamarckism and Darwin's Pangenesis), and what is now commonly believed correct:
Phenotypic plasticity
which states there exists a range of developmental variation within the individual. A good example of this is the high rate of increase in the average foot size of the U.S. male. It is not that our grandfathers had smaller foot size genes, or even that our feet are growing to keep up with body weight. Our ancestors just did not have the highly caloric and consistently nutritious meals that are consumed today, which pretty much voids any growth hindrance. We will find out if this is true if our grandchildren keep a similar diet and shoe size.

Because even Darwin miscalculated this mechanism, I think they are very important concepts for every biology student to understand. It took a vast failure of Soviet agriculture to put out common belief in Lamarckism, if I remember that right.
 
wookish;3186701; said:
Phenotypic plasticity
which states there exists a range of developmental variation within the individual. A good example of this is the high rate of increase in the average foot size of the U.S. male. It is not that our grandfathers had smaller foot size genes, or even that our feet are growing to keep up with body weight. Our ancestors just did not have the highly caloric and consistently nutritious meals that are consumed today, which pretty much voids any growth hindrance. We will find out if this is true if our grandchildren keep a similar diet and shoe size.

Because even Darwin miscalculated this mechanism, I think they are very important concepts for every biology student to understand. It took a vast failure of Soviet agriculture to put out common belief in Lamarckism, if I remember that right.
Click to expand...
do you have a better example or a better explained example, because i could view that difference as simply malnutrition, when a organism doesnt have enough nutrients it wont grow to its full potential.
a phenotype is just the displayed traits if i remember right. i view it as a body builder body increases muscle mass due to the stress of the training. i dont view that as anything incredible, just basic adaption. the body will attempt to adjust to the conditions to the best of its ability. but theres a point where the body can no longer adjust any more, therefore the animal dies. then only the animals that can adjust more then the previous animals live and pass down there genes. is this not correct?

@sweet
i just wanted you to know it wouldnt work in the long term, it just seemed to me you where attempting to say it would survive permanently in that salinity if you could get it down to it. also with the expirement im sure its been attempted numerous times before and the results werent considered worthy of attention.

heres some info about low salinity(not no salinity like yours):

with salt waterfish there is a treatment to destroy parasites called hyposalinity(or low salinity)(specific grav 1.009). I have heard if this treatment exceeds two months(a month is considered safe) the fish begin to show negative effects, such as a loss of healthy coloration and lack of appetite. some fish however seem normal for a few years, 3 years i think was the longest a fish every stayed in hypo


also many lfs keep there salinity slightly lower then normal seawater in a belief that the fish are actually healthier because they have less osmoregulation to do(s.g 1.019). but this has never been proven before



the reason the hypo is usually stoped around 1.009 salinity is it is the highest salinity that will be sure to kill ich(non attached stages of life). but it is also the relatively close to the the salinity of the fishes body. once you go down past that point the fishes osmoregulation must work in reverse the same way a freshwater fishes do. i think saltwater fish are in no way equipped to handle this in the long term, if they were we would see them more of them in brackish areas, not just the fish we label as brackish. personally i think any saltwaterfish that isnt found in brackish water and isolated from brackish areas, for some reason be it geographic or symbiosis reasons, etc, suggests that even low salinity water causes them discomfort.
 
You are right there sostoudt, feet are not the best example.. I came to my professor with the question of how it is possible that cases such as rapid foot size increase, and he did indeed give me the weight lifter example. The malnutrition, like regular weight lifting, are external factors that do nothing to change the coding of ones DNA. They do however factor in on how the individual expresses specific genes (phenotypic plasticity). (eg. possibly more cells with more mitochondria, hormone excretion, cell membrane transporters, ect.)

So by that rational, to comment on sweets post, Yes, many fish are able to survive under wide ranges of temperature and salinity. The damsels ability to survive such long periods points to andromonous relatives. Damsels are little tanks, however, being one of the least expensive tropic marine fishes for the aquarium trade because they are so prolific and hearty. If you tried the experiment with a more delicate species like a butterfly fish you would likely see quick death.
Plate tectonics often created inland seas in the past, or incorporated freshwater systems into the open oceans, rapidly changing salinity and other water conditions. In tropical settings I would consider damsels a pioneer in environments with lower salinity. Although I have looked briefly but could not find a similar experiment, -probably too late anyway as school is out for summer!
 
You must log in or register to reply here.
MonsterFishKeepers.com
Top Bottom