Following a thread with my kids about the fragility of the human body
- I was telling them "imagine having a pet so fragile, that as it walks, it may slip, fall, break its head and die. Thats how humans are. Walking accidents, top heavy, too much guts and brains, too little muscle mass and bone mass to keep things together. Imagine a dipod, like a chicken falling as it walks and injuring itself.
To accentate the difference I pointed out to felines like chetah that while running at 70mph lounge to their prey, bringing it down to the ground - something equivalent of jumping off a car at highway speeds - and doing that multiple times daily.
My smart-alecky kids, instead of being impressed from my points they jumped to tell me I am wrong and that cheetahs are not that fast (todays kids have grown with animal planet and know pretty well the largest, fastest,deadliest,smartest of any sort of thing) . Defending my speed claims I arrived at the cheetah wikipedia page (I was off by a bit, cheetah go up to 100-110km per hr, and they are an extreme case) where I was attracted to the following comment (and abandoned the not as satisfying discussion with my kids):
The cheetah has unusually low genetic variability. This is accompanied by a very low sperm count, motility, and deformed flagella.
That seemed interesting. Reading further the article went on to explain that this was caused due to a recent genetic bottleneck.
It is thought that the species went through a prolonged period of inbreeding following a genetic bottleneck during the last ice age.
What changed my view from interest to annoyance was that comment though:
It has been suggested that the low genetic diversity of cheetahs is a cause of poor sperm, birth defects, cramped teeth, curled tails, and bent limbs. Some biologists even believe that they are too inbred to flourish as a species.[45] Note, however, that they lost most of their genetic diversity thousands of years ago (see the beginning of this article), and yet seem to have only been in decline in the last century or so, suggesting factors other than genetics are mainly responsible.
See, my simple way to explain most of evolution effects to my kids, why I have black eyes, why my hair is thick and black why skin is this or that why swedish people are blond but Eskimos are dark haired, why our nose is less pointy than the chimps and the chimps nose is less pointy than other animals etc etc... all that includes a continuing combination of using
- fatal disadvantages
- strong advantages
to explain how a some particular member (or group) of a species was able to reach a certain level of environmental dominance/monopoply which often implies that this member will become a new Abraam patriarch/matriarch and explode its genetic tree - with most of the descendants carry the unique genetic characterists of nose, hair etc.
Its a relatively simplistic way to explain things - given the more incremental nature of genetic change ... still I think this model of explaining evolution is a very good one:
Where evolution happens the fastest when a relatively small sample of a species find itself owning a slice of the environment/geography , either due
- they were able to move to a new place due to their small incremental advantage
- they were they only ones to survive to the new place due to their incremental advantage
(new place - may be the old place + some new environmental change (draught, flood, new disease, newfound prey, newfound enemies, newfound resources))
and then genetically explodes to fill the "new place" until it reaches some sort of equilibrium.
The smaller the group that survives, the biggest is the genetic bottlneck(and following inbreeding) and then the big is the change that happens as a result.
Of course human morals are seeing inbreeding as synonymous to incest and thus wrong/bad.
Somehow that same morality made it all the way to scientific analysis and became a meaningful explanation -
- this species is too much inbred thats why it wont survive
- those species parents doesn't love/care for their offsprings that why it doesn't as well
- that species is cannibalistic, it kills and eats its own ..... why should we even put it in the endangered list if it does that to its own.
I get annoyed just writing it.
- I was telling them "imagine having a pet so fragile, that as it walks, it may slip, fall, break its head and die. Thats how humans are. Walking accidents, top heavy, too much guts and brains, too little muscle mass and bone mass to keep things together. Imagine a dipod, like a chicken falling as it walks and injuring itself.
To accentate the difference I pointed out to felines like chetah that while running at 70mph lounge to their prey, bringing it down to the ground - something equivalent of jumping off a car at highway speeds - and doing that multiple times daily.
My smart-alecky kids, instead of being impressed from my points they jumped to tell me I am wrong and that cheetahs are not that fast (todays kids have grown with animal planet and know pretty well the largest, fastest,deadliest,smartest of any sort of thing) . Defending my speed claims I arrived at the cheetah wikipedia page (I was off by a bit, cheetah go up to 100-110km per hr, and they are an extreme case) where I was attracted to the following comment (and abandoned the not as satisfying discussion with my kids):
The cheetah has unusually low genetic variability. This is accompanied by a very low sperm count, motility, and deformed flagella.
That seemed interesting. Reading further the article went on to explain that this was caused due to a recent genetic bottleneck.
It is thought that the species went through a prolonged period of inbreeding following a genetic bottleneck during the last ice age.
What changed my view from interest to annoyance was that comment though:
It has been suggested that the low genetic diversity of cheetahs is a cause of poor sperm, birth defects, cramped teeth, curled tails, and bent limbs. Some biologists even believe that they are too inbred to flourish as a species.[45] Note, however, that they lost most of their genetic diversity thousands of years ago (see the beginning of this article), and yet seem to have only been in decline in the last century or so, suggesting factors other than genetics are mainly responsible.
See, my simple way to explain most of evolution effects to my kids, why I have black eyes, why my hair is thick and black why skin is this or that why swedish people are blond but Eskimos are dark haired, why our nose is less pointy than the chimps and the chimps nose is less pointy than other animals etc etc... all that includes a continuing combination of using
- fatal disadvantages
- strong advantages
to explain how a some particular member (or group) of a species was able to reach a certain level of environmental dominance/monopoply which often implies that this member will become a new Abraam patriarch/matriarch and explode its genetic tree - with most of the descendants carry the unique genetic characterists of nose, hair etc.
Its a relatively simplistic way to explain things - given the more incremental nature of genetic change ... still I think this model of explaining evolution is a very good one:
Where evolution happens the fastest when a relatively small sample of a species find itself owning a slice of the environment/geography , either due
- they were able to move to a new place due to their small incremental advantage
- they were they only ones to survive to the new place due to their incremental advantage
(new place - may be the old place + some new environmental change (draught, flood, new disease, newfound prey, newfound enemies, newfound resources))
and then genetically explodes to fill the "new place" until it reaches some sort of equilibrium.
The smaller the group that survives, the biggest is the genetic bottlneck(and following inbreeding) and then the big is the change that happens as a result.
Of course human morals are seeing inbreeding as synonymous to incest and thus wrong/bad.
Somehow that same morality made it all the way to scientific analysis and became a meaningful explanation -
- this species is too much inbred thats why it wont survive
- those species parents doesn't love/care for their offsprings that why it doesn't as well
- that species is cannibalistic, it kills and eats its own ..... why should we even put it in the endangered list if it does that to its own.
I get annoyed just writing it.
A related article just made it to HN first page....
ReplyDeletehttp://www.slate.com/blogs/wild_things/2013/10/28/sea_otter_dolphin_and_penguin_behavior_your_favorite_animals_are_jerks.html