Auburngirl05

 

Interbreeding among relatives only increases the chance of downe syndrome if there is a history of it right?

No' date=' the triple chromosome #21 that causes the disease results from an operational error, it is not a mutation of the chromosome like some other chromosomal disorders that [i']can [/i] cause birth defects.

To answer your question directly, the chance increases with inbreeding only if your interbreeding relatives include elderly women, but that applies to any breeding population. You can't inherit a nondisjunction. Do some reading on the meiosis process, it will explain aneuploidy.

 

Interbreeding among relatives only increases the chance of downe syndrome if there is a history of it right?

No' date=' the triple chromosome #21 that causes the disease results from an operational error, it is not a mutation of the chromosome like some other chromosomal disorders that [i']can [/i] cause birth defects.

To answer your question directly, the chance increases with inbreeding only if your interbreeding relatives include elderly women, but that applies to any breeding population. You can't inherit a nondisjunction. Do some reading on the meiosis process, it will explain aneuploidy.

you can if you have a downe's parent. they are not sterile.

As several others in addition to me have stated, you can't inherit a nondisjunction, it's a "mechanical" error in DNA replication.

Much like what muad'dib said, I don't think there's an allele for it, you can't inherit the nondisjunction that causes the triple 21st chromosome.

For some reason the risk of Down's (and other diseases resulting from aneuploidy) increases as the age of the mother increases, with the ratio rising from ages in the early-mid thirties onward. I'm fairly certain that it's one of the conditions tested for with an amniocentesis.

I wasn't looking for a reaction like that, sorry if the post irritated anyone. I thought a thread with people's pictures of themselves would be interesting, although I agree they should definitely be tasteful pictures...

I've posted pictures on boards before but I couldn't get it to work this time for some reason, anyway, my pics can be found here:

http://groups.msn.com/Anne-MariesPlace/shoebox.msnw?action=ShowPhoto&PhotoID=73

http://groups.msn.com/Anne-MariesPlace/shoebox.msnw?action=ShowPhoto&PhotoID=74

http://groups.msn.com/Anne-MariesPlace/shoebox.msnw?Page=1

I’m trying to find information about the long-term effects of malnutrition on cardiac muscles. I know that emaciation weakens the heart muscle and have read of “sudden cardiac death” and increased risk of myocardial infarction, but haven’t had much luck with finding detailed descriptions/statistics.

The hypothetical type of case that I’m interested in is a female who received good nutrition as a child but became malnourished and underweight around age 13, staying under recommended weight for at least five years and also having amenorrhea. (Basically, anorexia cases).

How reversible is damage of this sort? Are there any specific vitamin supplements that would be especially beneficial in a case like this? Also, I’d be very interested in reading explanations of the exact physiological reasons/processes for “sudden cardiac death,” not that I’m doubting that it’s a risk, it’s just that most of the resources I’ve found have been a little vague on exactly what happens to cause it.

Any information is extremely appreciated, thanks for your time.

I'll be starting as a freshman at Auburn University next fall (it's in Alabama, although a bit far from your version of Birmingham, YT2095, ) I'll be a Zoology/Pre-vet major so most of the headlines about them that I've taken interest in have been in that field...

They recently implanted a new cardiac device at a gorilla living at the Montgomery Zoo: http://www.vetmed.auburn.edu/index.pl/news/babec, and they have a Canine Research and Detection Institute that developed a special formula of dog food to enhance the olfactory capabilities of professional scent. detection dogs.

P.S. What is the name of the one-celled organism we all started out as? Started with a Z' date=' forgot it... [/quote']

Do you mean zygote?

 

I'm also a high school student, and I have to say that science is the one class that really fascinates me and makes me think, I love to know how and why things are the way they are, and learning basic principles of biology, chemistry, etc can provide lots of "aha!" moments about things in every day life. I'm looking forward to college with the wide range of classes to choose from...so no, I don't think you're crazy, and if you are then you're in good company.

Evolution of intelligence in predators vs prey is kind of an interesting study in coevolution (arms race style), but it seems generally accepted that predators tend to dominate when it comes to brains, obviously, I guess, because they could never survive if their prey outwitted them every time. Here are some related links if anyone is interested:

http://www.adelphiasophism.com/wls/080genesandexplosive.html

http://zebu.uoregon.edu/1996/ph123/l14b.html

http://bioweb.usc.edu/courses/2003-spring/documents/bisc313-geiger_Coevolution.pdf

And a game that I thought was creative, I didn't try it out or anything, just saw it and thought I'd pass it along:

http://ethel.as.arizona.edu/~collins/astro/subjects/evolve-16.html

If you're talking in terms of trainability, definitely dogs, although some breeds of dogs tend to be much more trainable than others, it's all relative. Rabbits are a prey species, and dogs were predators (originally), and correct me if I'm wrong but I think it's pretty accepted that predators tend to develop higher intelligence (not in all cases, but as a general trend). It takes a little more thought to capture a rodent for dinner than it does to capture a patch of grass.

I'm kind of an exercise fanatic, so I run every day...when I'm just doing a short distance I can do a mile in about seven minutes flat without pushing too hard, but when I'm doing distances I keep it to 7.5 minute miles, I think it's about 8 miles an hour...I don't know the conversions off the top of my head for those that are used to metrics, sorry.

Looks like wounded national pride. One suspects that Flores man is about to take a back seat to Homo iratus academius.

 

I think you're right, that's probably the main factor, all of the criticism of the Australian researchers seems to be mostly bitterness about being "beaten" to the story.

Also, there could be some paranoia over racial issues for the Indonesians, such as concern over the finds implying that people in that region descended from an inferior lineage, which is nonsense, in my opinion, but a lot of people have read close to nothing about evolution and are easily led to dangerous conclusions like that...

Just an update on the discussion going on among scientists about the finds...these statements really surprised me and I'd expect them to cause some controversy/argument among professionals...

http://www.thejakartapost.com/yesterdaydetail.asp?fileid=20041106.A05

You could do a study on the controversy over mesonychid versus artiodactyl ancestry for whales, I believe the latter has recently been considered to be the stronger case, and you could highlight the fossil record of wrist evolution as evidence.

http://www.sciencenews.org/articles/20010922/fob1.asp

It could make a fascinating doctoral study. Of course the downside is that you would have to visit places like the Bahamas, the Seychelles, the Maldives and Fiji for your field work.[img']http://www.scienceforums.net/forums/images/icons/icon7.gif[/img]

It would also be interesting to see a studies on populations in impoverished African countries where severe malnutrition is the norm, please correct me if I'm wrong because I don't know it for a fact but I think they still tend to be average height or even taller...

Another interesting study would be the average height differences in groups with the same food intake in terms of caloric value but from foods of different sources (like Eskimo meat-based diets versus a vegetarian diet, and the results of adaptations to each). Discover magazine did a recent article on Eskimo diets that was pretty interesting.

Sorry that parts of my above post repeat others, I think I was posting at the same time as a couple of other members, who obviously have faster fingers than me.

Can the dwarfing principle be applied to ectothermic animals with that have indeterminate growth (ones that never stop growing, such as many types of reptiles: gators, turtles, anacondas, etc)? I'm not being rhetorical, honest question.

I would think that it wouldn't apply, seeing as how huge monitors and of course komodos thrive on islands, although that could also be explained alternatively because the predator role obviously provides them with a better quality of food than a hunter/gatherer would rely on.

But that factor comes into play when discussing crocodiles and alligators....and I honestly don't know enough about reptiles to know the degree of indeterminate growth various reptiles can have, obviously some grow to consistently larger sizes than other species do...any insights from someone more not as reptile-illiterate as I am?

Now that I think about it, though, dog breeds probably don't have much value as far as evolutionary fitness goes, the vast majority are semi-mutants thanks to humans' fascination with anatomical oddities, lol...

Thanks for those links, even though this isn't "my" thread I appreciate you sharing them, those are some good resources, I knew of Talk Origins but not the others.

Intelligence is not strictly related to size. I mentioned several examples in an earlier post. For another example take very small dogs. Many people claim that small dogs are actually smarter yet their brain size is reduced (I think' date=' I couldn't get an exact conformation on this). [/quote']

 

Remember that reduced brain size in dog breeds would result in relatively constant body/brain ratio, meaning even normal intelligence in a smaller brained chihuahua shouldn't be surprising. True, that ratio does not always indicate intelligence, but small dogs are not considered to be smarter in general, on a widely accepted ranking list only two of the top ten breeds are under 45 pounds when mature. http://www.petrix.com/dogint/1-10.html Most working (aka thinking) breeds tend to be at least medium sized, with some exceptions, and I would assume their brains differ in important ways besides size from similar sized or even larger breeds with lower intelligence.

 

One interesting and entirely irrelevant note: eyeball size is constant in all dog breeds, from Danes to Yorkies. (I work for a vet and am full of useless info on dogs, lol)

If you're looking for a very well illustrated evolutionary line, the fossil record of the evolution of horses is fairly complete, from the first Eohippus all the way to modern Equus. Whale evolution also has quite a few specimens of "fossil evidence."

Marsupials provide great examples of convergence, also, a variety of placentals from bats to moles to lions have (or have had in the past) marsupial counterparts due to adaptations to similar niches.

I would think that "shrinking", or evolving a smaller body size than other Homo species, would be a strategy to preserve brain power, if there is less body the brain can maintain its function on less energy, with no need to sacrifice intelligence. I honestly don't think they would have evolved into less intelligent individuals, especially if they had to rely on their wits to avoid becoming prey for komodos.

There have been studies done on anorexics that show significant brain shrinkage due to malnutrition, but as far as I know it doesn't significantly affect intelligence later if they recover and restore healthy physical condition. Not that it is entirely relevant when discussing evolution, just thought it was interesting to note.

http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v392/n6672/abs/392173a0_fs.html

http://www-geology.ucdavis.edu/~cowen/HistoryofLife/erectusatsea.html

Sorry about the link problems, see if those work any better. If it still doesn't cooperate, you could run a search from the Nature website, the article was in the March 12, 1998 issue.

I came across this page on the UC Davis website, and thought it was

pretty interesting, it cites a _Nature_ article that apparently

foreshadows the recent Flores finds.

http://www.geology.ucdavis.edu/~cowen/HistoryofLife/erectusatsea.html

The abstract for that article is here: http://www.nature.com/cgitaf/DynaPage.taf?file=/nature/journal/v392/n6672/abs/392173a0_fs.html , I'm not a

subscriber so I couldn't access the whole thing but I thought I'd

pass that much along at least, it was definitely interesting to read

earlier conclusions on the topic and compare them to the current theories that are being put forward.