Some of my answers that I gave on Y! Answers. Just showing off!
1.
What is the evolutionary pressure that caused polynucleated cells to form in some protists?
I also would like to know (and this may be cheating asking another question here but...) Does each nucleus contain an identical set of DNA? How does mitosis work with these little guys??? Thanks!!!!
Answer- Great question! And no, I won't call it cheating if you add another follow-up query. It's good to be inquisitive.
Now, to answer your question precisely, there was no evolutionary pressure that caused polynucleated cells to form in protists as such. The factors that affect evolution viz. natural selection, genetic drift, gene migration, recombination and mutation cannot (with the exception of mutation) cause the appearance of a certain morphological trait as effectively as they can help the organism to sustain it. The answer actually lies in the second question you asked. Yes, mitosis. To state it briefly, yes, each nucleus *does* contain an identical set of DNA. The reason why cells are different functionally in multicellular organisms is because of the effects of certain gene mechanisms that "switch off" and "switch on" the production of enzymes under specific conditions thus, altering their functionality. Now, to answer your primary query-- as you already might be aware that during the cell-division, it is the nucleus that first divides into two: (Mitosis). Sometimes, the outer membrane of the protist fails to separate due to the lack of phospholipid membrane material. This delay in cell division back in the days of the beginning might have resulted in a polynucleated cell. The success of this polynucleated cell may be easily justified due to the increased efficiency of the metabolism as the decentralisation of regulating power i.e. nuclear material could have resulted in division of labour and thus, in perhaps the first *ever* "pseudo"-multicellular animal. As for your follow-up queries, I think I have provided enough detail in the paragraph above, which you can use as a *very* basic outline and explore the subject further by studying the topic in detail in your book(s).
Q2- What is the exothermic natural process that keeps the heat inside the Earth's atmosphere?
Answer- That's a nice question in my view.
In few words, the answer is-- "the exothermic process of air molecules moving towards the earth keeps the heat inside the Earth's atmosphere."
Ok, now, here's my answer in detail-
Your question can also be read as- "Work must be done to hold heat and keep it from escaping earth's atmosphere. By whom is this work done and how?"
Now, as you already might be knowing that heat is held by gases on earth's surface and the gases (atmosphere) in turn, are held by the gravitational pull of earth; I think it might be enough just to give you a background on "HOW" greenhouse gases hold heat and what energy is spent in doing so.
Let's take the most common greenhouse gas -- carbon dioxide (CO2) to demonstrate the process. Here we go!! First, UV rays and visible light enter earth's atmosphere. UV rays are absorbed by ozone and visible light reaches and heats up the earth.
Now, an exothermic process takes place. Earth cools down and releases heat in the the form of infra-red waves or IR waves. Now, these IR waves have a heating effect. They strike the molecules of CO2 and other gases in air and heat them up.
The excited molecules of CO2, methane and others are kept from escaping the atmosphere by the gravitational attractive force.
Now, this gravitational attractive force attracts the greenhouse gases which are loaded with heat. Attraction results in an energetically stable state of the earth-air system. Stability can be attained only by reaching low-energy state.
So, the movement of greenhouse gases TOWARDS the earth DUE TO earth's gravitational force of attraction is the EXOTHERMIC natural process required to keep the heat inside earth's atmosphere.
You might ask that what's the use of moving towards earth and losing energy if the sole purpose of the process is to KEEP energy. The answer is-- the movement isn't a mass movement. The molecules that constantly feel the attraction but don't move towards earth are actually the ones waiting for the molecules under them to heat up and move upwards so that they can come down and release their energy ONLY to gain the energy AGAIN from earth's surface.
Also, it's not that no heat is ever lost from the atmosphere. The atmosphere is ever-dynamic and all the heat which enters the atmosphere, constantly leaves it too. It's just that it leaves a little late. That's all.
I hope my answer made sense.
Q3- Inflated balloon is put in a refrigerator and it shrinks. How does the first law of thermodynamics apply?
Answer- Good question!
First law of thermodynamics states that the internal energy change ΔE of a system is equal to (Q - W). Where Q is the heat absorbed by the system and W is the work done BY the system on the surroundings.
Now, as you already might be knowing that work can also be expressed in terms of pressure and volume as-
W = PΔV (where P is pressure of the gas inside the system and ΔV is the change of volume)
[Here: "system" = balloon; and "surroundings" = refrigerator]
And as the change in volume (ΔV) in the case of balloon stated above is negative i.e it deflates, work must be negative i.e (minus W).
Now, as Q is also negative (heat is given off by the balloon), the equation of First Law of thermodynamics reads-
ΔE = -Q - (-W)
ΔE = W - Q
Now, if the balloon was large in volume, the change in internal energy ΔE would be positive and the balloon will either burst or move frantically in the refrigerator shelf.
But, if the balloon was a small one, it'd slowly become limp and deflate as the Q will overpower W (PΔV) in the equation and the internal energy ΔE will decrease and become negative.
Please note that I have made a lot of assumptions here that perhaps, might not be so easy to apply practically.
The points you'd have to consider are:-
1-How tightly the balloon is wound so that air doesn't leak out of it.
2- Whether or not there's a leakage in the balloon.
3- The temperature of the balloon.
4- The material of the balloon.
Strictly speaking, the first law isn't even applicable in this case because the condition in the law is that the system (balloon) shouldn't be allowed to move. Its kinetic and potential energies should both be zero which clearly is not the case with our experiment.
I hope this answer helps!
Good luck!
Q 4- What is the difference between contemporary, literary and mainstream fiction?I'm just curious. I believe literary is more towards magazines, right? I'm just curious in what work might novel might be under other than thriller and general adult fiction.
Answer- Good question. I wonder what has kept others from answering it. Anyways, I'll give it a shot. Hope you like my answer.
Contemporary fiction, as the definition of the word "contemporary" implies, belongs to or is about the issues and scenarios of the same times in which it is composed. Aside for serving as a pleasurable read, this type of fiction is often used as a tool to awaken the masses. Robert Browning, William Wordsworth et al used their pens to address the sociological issues of their times and helped invoke a sense of awareness about the ongoing political scenario among the readers. Contemporary fiction is "with the times, for the times" type of material with a picture of sociological scenario of its age. Literary fiction is appreciated and read by a niche audience. It can fall into any of the sub-generes viz., Mystery, Romance, Sci-fi, Women's fiction, Horror etc. but, it has a certain unapproachable aura around it that the common man commonly decides not to indulge much into. Literary fiction has a small and intellectually adventurous audience which appreciates its intricacies, originality and the adroit narration. Cold Mountain by Charles Frazier (Atlantic Monthly Press, 1997) is an example of Literary fiction. Mainstream fiction is the one for the masses. It can be literary or commercial, horror or comedy, suspense or romance. Vaguely, all the best-sellers of 20th or 21st century are considered to be mainstream. Sue Grafton, Arundhati Roy, Michael Crichton and David Guterson are a few of the "mainstream" authors. This fiction mostly addresses personal conflicts, coming of age stories and love matters etc. The plot is intended to be identifiable by a common people from the world over. ~Now, lemme answer your follow up questions~ Literary isn't more towards magazines. The term you might be looking for is "commercial fiction". This attracts a broader audience and can fall under any sub-genre. Most important attribute of it is its sellability or marketability. The quality is compromised for brevity and emotional drama factor in this type. Also, please note that thriller and general adult fiction can fall under any of the broad genres of commercial, literary or mainstream fiction. I'd say it'd be better and safer to call Romance, Thriller, Fantasy, Horror, Adult, Young Adult etc. as sub-genres of fiction instead of genres. "Genre" refers to a broader array of classification under any of which these "sub-genres" can fall. For example, a "Thriller"can belong to any "genre" from commercial to literary and from mainstream to contemporary! Happy reading. I hope my answer didn't bore you. I tried to explain the best I could and yes, I did consult a few books before answering
Q 5- How do u remove the jaws from a shark?
Update : for u there, that's cause u don't have one!
and for the rest, its not like i'm going to do it or anything, its just my teacher wants me to find out, for extra credit.
Update 2: if they are in a shark's mouth
Answer- Actually, your teacher has asked a very good question. First of all, you would need to know what type of teeth are found in a shark's mouth and whether or not you could use a pair of Mr. Dentist's tongs to pull the teeth out.
A shark has backwardly directed acrodont teeth. Acrodont teeth are those which are directly attached to the jaw bone (unlike our thecodont teeth which are pitted in the sockets of the jaw bones).
One more thing to note is that sharks belong to the class Chondrichthyes (the class of marine fishes with cartilaginous endoskeleton) of subphylum Vertebrata. In simpler terms, the skeleton of a shark is made up of cartilages and not bones.
With that much information, we can say that it is not possible to pull out a shark's teeth because it is directly attached to the jaw bone. But, you can use a sharp object to saw the tooth out as (being cartilaginous) it is softer than that of a bony fish.
P.S. Please understand that it'd be very inhumane to deprive a shark of its only weapon of defence and offence i.e its teeth. It'd die without them.Your teacher intended to know how much you know about a shark's endoskeleton while posing the question. What? You already knew that? oh okie..
Good luck!
Q 6- How do you go about taking the pulse of a city?
not literally, but figuratively: what do you look for to see if a city is happy, healthy, ALIVE?
Answer- The "pulse of a city" is a pretty subjective term and can be read differently by different people. (Don't be disappointed yet! I am coming to the point....!) However, those who live, commute and socialize in a city over a substantial period of time form common opinions about its citizens, its literature, its civic amenities, its crime rate, local politics etc etc.
These opinions, when discussed over a cup of coffee in the city's busiest restaurant are overheard and ruminated over by the relatively unexperienced denizens of the city.
Face-to-face discussions (if you call sitting in front of an old guy and listening to all that he has to say- "discussion") with retired professors, teachers, writers, journalists and others whose jobs involved an awareness of "what's going on these days" can also fill you up with a sense of the current pulse of the city and can also lend you with the ability to detect the fluctuations in the pulse in future.
To detect whether a city is alive and happy is easy. I would call it looking around instead of feeling the pulse. The pulse is something else (at least to me).
If people help you out, shopkeepers smile and say thank you, neighbours treat you as family (Yes, that still happens; here in small-town India)... the city would be considered happy and alive.
Every city has its own pace. Metros like New Delhi or Mumbai are busy fast-paced cities. Smaller cities like Agra, Gwalior, Jhansi have more time on their hands. You'd see tastefully decorated drawing rooms in Delhi and think professional home decorators but, in Gwalior, you'd expect that the housewife of the home, or the elder child has crafted those woodworks, decoratively knit fabrics and paintings etc.
These differences in decor give you a sense of the pulse and pace of the city. I believe that the (model) drawing rooms, if closely examined, can serve as great indicators of the pulse of the society. (Do not base your judgement on one or two examples though).
The percentage of youth in malls, cafes, restaurants, parks etc. can also help. The more the young faces, faster is the city!
It is easy to form opinions about the city on the basis of its overall look. What is tricky is to "know" what the crowd thinks. It is just too many opinions, too many voices.
If there is an urgency in your endeavour to detect the pulse, you can go out on one Sunday afternoon and observe faces. If you mingle well enough, you'll return with the threads of city's pulsating linen stuck in your nails and between your teeth (figurative... :)).
Q 7- What initiates parthenogenesis?
please don't tell me what parthenogenesis is. i already know. what i want to know is what causes it? thanks in advance.
Answer-
Really interesting question this one. Let me try and answer it- In 1936, Gregory Pincus induced parthenogenesis in mammalian (rabbit) eggs by temperature change and chemical agents. While keeping in mind the possibility of artificially introducing parthenogenesis, let's discuss the conditions that might cause parthenogenesis- In colonies where males and females live together, there is slim chance of occurrence of parthenogenesis as once sexual reproduction is underway, it is difficult to turn back. The complex mechanisms of sexual reproduction make it evolutionarily difficult for an organism to go back to asexual or vegetative forms of reproduction. Also, the presence of a male negates the need of parthenogenesis. But in aphids where some species like Brevicoryne brassicae (cabbage aphids) are all females, parthenogenesis is the only way. When in nature, a female population or individual is deprived of male intervention, natural selection and evolution make way for parthenogenesis. As you already might be knowing, in higher mammals, progesterone secreted from corpus luteum raises the body temperature and helps in converting the proliferative endometrium into a secretory lining receptive for implantation. If in a chance occurrence, the secretion of progesterone stays there for a longer period and the body temperature as a result also, is higher and thus optimized for implantation-- the ovum might undergo mitosis and act as a zygote. The ovum already has the cytoplasmic content and the genetic information. It is just that it is haploid (which also might not be the case if the parthenogenesis is apomictic i.e. non-meiotic). The only reasons for it to not act as a zygote are genetic. It is supposed to wait for the sperm but what if it doesn't? There is nothing stopping it from chancing upon parthenogenetic reproduction. So, if one chance occurrence of the ovum being developed parthenogenetically gets successful, it may lead to a whole bunch of parthenogenetic individuals living happily ever after! You might observe in the third link given in the source section that some species like humans and apes cannot reproduce parthenogenetically because the embryo dies due to genetic reasons but still, the development of a haploid embryo shows that there IS a possibility always. Now, coming to the Gregory Pincus experiment where he experimentally made parthenogenesis possible, you can easily see that regular administration of progesterone and higher body temperature can provide continuous suitable conditions to the rabbit's ovary which ultimately results in parthenogenesis. I hope I was able to answer at least a part of your question.
Q 8- What is the best way of making a protagonist seem morally questionable without having them be instantly 'bad'?
I have an idea for a new written project in which the protagonist must have questionable moral fibre but not be instantly unlikeable, or roguishly appealing either.
What is the best way of accomplishing this? And if they are to die, how can I make them finally redeem themselves without it seeming 'corny'? Is it perhaps best for them to remain unchanged by the events of their story and, if so, does this make them automatically villianous?
Thanks!
Answer- Hey!
Nice intriguing question, David. Hmm.... questionable moral fibre and we can't justify the means too little or too much, eh?
Here are a few ways, in my opinion, to do that-
1) Tie the protagonist to one incident.
Many authors do that so, in that way, it is a bit stereotypical but you can try it and have the readers think with the character's viewpoint too. Then, at one point or the other-- have the protagonist do something which was a tad extreme a response to that particular incident.
Let the character have a fixation with a tragedy in his life and justify his doings on the basis of it. Then, at points-- let the reader think that the character should let bygones be bygones now. I don't know... am I clear enough?
2) Give the protagonist a psychological disorder.
A disorder like schizophrenia, Obsessive Compulsive Disorder or any of the sort may cover up the character's abnormal or slightly dark behaviour just about right. In addition to that, it will intrigue the reader as he'd like to know what goes through the mind of someone who's not psychologically normal.
3- Give the protagonist a philosophy about life.
A different philosophy like hedonism. Spread out the word about this new philosophy by the impressive dialogues and quotable quotes from the protagonist in the beginning. Later, the reader will begin to follow and at the same time, dislike the character.
4- An extremely good sense of humour can help.
The protagonist may make jokes that can make up for the lack of morality but, for that, first you need to have a good sense of humour which only comes from observation. Don't go over the top with sick or extremely derogatory jokes... just let the reader know that the protagonist has emotions and is observant of all the fear and agony that surrounds him. He just refuses to be frightened or agonized anymore.
Ok, I am out of ideas for now. Good luck with your project.
Coming to the second part, I don't think making them redeem themselves it a great idea. There's no way to make it possible without drastically changing the character sketch of at least one character which is always risky.
This doesn't make your character automatically villainous. A good villain, if you call him villain, is never all black. So, maybe the funny protagonist dies not before churning out one last funny joke or the philosophical protagonist dies with full faith in his thinking and philosophy and that'd do it. Rest lies in your execution of all this.
Good luck and have fun!!
Love,
Abhyudaya (Batman)
Gwalior, India
Q 9- Has Anyone written a poem about the brain?
I need to write a poem and was wondering if anyone has a poem i could refer too Thanks
Answer- In which year was Mahatma Gandhi slain?
what is the name of your favourite restaurant chain?
Answers to all these, and much more,
are stored in my head, within my brain.
Oh what a magnificent organ,
is the brain.
It reminds you to take the umbrella,
when it's about to rain.
It helps solve those math sums,
without much strain.
You can memorize stuff,
and throw it down the drain.
It's like a giant corn cob,
our small little brain,
with inscriptions in each,
and every small little grain.
Q 10- Modern Human Evolution? How did all populations of humans advance at the same time?
For approximately 150-200,000 years, humans essentially lived like very smart animals, then fairly suddenly, about 10,000 years ago, we all seemed to have discovered agriculture and "civilization"..a few thousand years later we were all writing. I have never seen a decent, logical explanation for how all the populations of the Earth took this "great leap forward" at the same time-After 150-200,000 years, suddenly within about 1% of that time frame, there are cities everywhere from the Middle East, to China, to North and South America? Writing starting independently everywhere? For me, this is the most mysterious event in all of history-any ideas?
Answer- I'll try to make sense while talking about a topic that I know little about.
1- It all started with the arrival of the first bipedal- Australopithecus anamensis. (some might argue that it was Ardipithecus ramidus). Ok, the point is, as our ancestors started to learn to walk on two feet, they had some challenges to face as bipedalism reduced their speed considerably putting them at a clear disadvantage against their predators.
Now, as this problem was faced by all the hominids all over the world at the same time, it led to some parallel thoughts (and thus inventions and discoveries) all over the world e.g. building homes, making weapons and tools etc. (The stone tools were first made by the handy man i.e. Homo habilis and not Australopithecus).
This tool technology was spread by Homo ergaster as they migrated outside Africa.
2- Then, in the course of evolution, the early humans started to have a complex cultural lives and they grew emotionally, e.g. the Neanderthals (who aren't our direct ancestors) started to bury the dead.
3- As the homo species like homo erectus, homo neanderthalis, homo heidelbergenesis and ancient homo sapiens (Cro Magnon) made further advances in creativity and productivity, they all felt a natural need to pen down their thoughts. This led to the cave painitngs and carvings. All of those paintings can be interpreted as diary entries as you may see that the paintings and carvings simply depict what the early men "did" i.e. hunting, using tools etc.
So, I guess it is understandable why the "pictorial-scripts" developed contemporarily to each other.
4- But the question still remains: Why were the origin of world's ancient scripts so contemporary to each other? I guess, as man found the pictorial depiction of thoughts and emotions more and more unconvenient and tedious due to the diverseness of thoughts and situations to be depicted, it started taking help of symbols. Perhaps, this behaviour was so "human-like" that every sub-species of the homo sapiens followed this pattern of 'depicting thoughts symbolically' universally.
5- Another reason of this might be migration. Before the ancient civilizations like Inka, Mesopotamia, Egyptian etc. even came into existence, the early hominids led a nomadic life. According to the "Out of Africa Hypothesis", all the modern humans "Homo Sapiens" originated from Africa. Later, they migrated to Africa, Asia and Europe and formed groups.
So, I guess due to their similar ancestral origins, the human beings had a common problem solving approach and hence, attempted the problem of inconvenience of pictorial scripts in a nearly identical manner.
The scientific difference in the scripts can explain that they were devised on completely different grounds but, the approach was similar due to common origins and creative grounds.
Q 11- Physicists and chemists: Strength of nuclear string?
Just from a science-fiction idea viewpoint. If one could construct a string or rope from nuclear material only (in other words, an atomic nucleus that was very long in one dimension), how would you calculate the physical strength. This is a question of converting nuclear binding force to physical "Kg weight" force. Thanks
Update : Ah-Good start-My question was very poorly stated, because one would have to know the binding energy between two nuclei, not the binding energy normally found in molecules, such as covelant binding. I had once read that the strongest physical material would be hydrogen nuclei directly binding, but I cant find anything to address this, so I dont know if it's even physically possible. Thank you for answering though, at least I have a mathematical framework.
Answer- Well, I can't even imagine what you are trying to let us picture but, at the same time, I feel this question must have at least one answer so, here I go without having a clear picture in my mind and perhaps lesser knowledge than required to answer this question-
Lets first imagine that this fictitious rope is made up of x number of neutrons and y number of protons.
Now, Mass of x number of neutrons = "x" multiplied by 1.00864 atomic mass units.
And mass of y number of protons = "y" multiplied by 1.00727 atomic mass units.
Now, total "expected" mass of the rope = "x" multiplied by 1.00864 atomic mass units + "y" multiplied by 1.00727 atomic mass units
To Convert total "expected" mass of the rope from a.m.u. to kilograms :-
Use the relation- 1 a.m.u. = 1.66 * 10 raised to the power (-27) kg.
Now, weighing the rope, we will find that the actual mass of the rope is lower than the expected mass. Let the diference between the Actual mass and the expected mass be [M], now as Einstein told us:
E = mc^2
We can express this mass difference as:
Binding energy = [M] c^2
I think that to determine the physical strength of this rope, one shall have to divide the Binding energy obtained above by the total lengh of the rope.
After doing so, you'll get the value of the physical force that is keeping the rope intact.
Q 12- "Biochemistry" of alien silicon creatures?
Silicon is much like carbon chemically, but the Si-O bond is much stronger than the C-O bond, and that is thought to result in reduced possibility that silicon creature would exist. Are there conditions under which the stronger Si-O and Si-H bonds would be as easily broken and organic chemicals, such as high heat? This is another science fiction-like question. Thanks
Update : Thanks Batman-please feel free to answer anything else- It sounds like you are describing a Venus-like planet...though would that be too extreme (800 C)?
Answer- Wow! another brain-tickling question from Neuro-Prof! What imagination! Yeah, that would be pretty interesting to see. I think a planet with such conditions will be a home for people who'd be considered super-heros by us on earth. Silicon would make their skin rough and abrasive. That would be just awesome!
Now, coming to your question, I think the conditions that would favour such an atmosphere should be-
1- Extremely high pressure. Pyrolysis is one of the methods to break Si-H bonds.
2- Extremely high temperature.
3- Reducing Atmosphere / Abundance of Dihydrogen. As compared to our earth's oxidising atmosphere, a reducing atmosphere would contribute a lot more in breaking the Si-O bonds.
Great question, I must say.
