Evolution Definition and 692 Threads

why is there very rapid mass loss in the superwind phase. my notes simply say "because the envelope attains positive binding energy". Firstly, how can binding energy be positive by definition?! Secondly, I am not entirely sure what the lecturer is talking about? what makes the envelope...

why after hydrogen exhaustion (of low mass stars) does the the core become isothermal. (according to my notes) I mean, after exhaustion, its all helium, and it keeps on contracting right? So by the virial therem it must heat up (so by definition, it is NOT isothermal)! Indeed it must do so...

we well know that, a coherent state keeps to be a coherent state in its evolution does similar conclusion hold for a squeezed state?

I read in my textbook that the wavefunction of a particle evolves causally when unobserved. but isn't it constantly being observed or detected in some sense by its gravitational effects?

Evolution: 24 myths and misconceptions The following myths are debunked: - Everything is an adaptation produced by natural selection - Natural selection is the only means of evolution - Natural selection leads to ever-greater complexity - Evolution produces creatures perfectly...

http://www.sciencedaily.com/releases/2008/04/080417112433.htm In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the South Adriatic Sea, to the neighboring island of Pod Mrcaru. “Striking differences in head size and shape...

[SOLVED] Evolution Operator If U=Exp[-iHt/h] is the evolution operator, and H the hamiltonian one, i can't figure out how to derive the following equation. Let`s call |E> an eigenstate of H, E it`s eigenvalue and |J> a random basis. Then: <J|U|E>=Exp[-iEt/h]*<J|E>. ??

I have a question about the Dirac Equation. I know that if I have a given initial state in non-relativistic quantum mechanics, I can find the Fourier coefficients using that state, and then write down the wavefunction for any time. But if I have an initial state wavefunction (that is, the...

stellar evolution pathways...? I find this especially interesting since the trajectories of stars on the HR diagram are more or less based on this assumption. But obviously, small perturbations can lead to major changes in the long-run. But it seems that most of those changes involve only...

I want to clairfy something: Is it true that without DNA mutations it would be impossible to start with a population of x wild wolfs and breed a chihuahua, or poodle? Lets say your only goal is to start with a very large population of wolfs who on average weigh 100 lbs, your goal is to create a...

In case you haven't already heard, when the Republican Candidates were asked, "Who doesn't believe in evolution?" 3 of them raised their hand. If you didn't see it, I attached the clip below...

How does evolution work? It seems that evolution has determined many of the circumstances of the world we find ourselves in. Here are a few examples: (1) Cosmologists tell us that our present astronomical universe --- a conglomeration of planets, stars and clustered galaxies, together with...

Is there any reason that evolution can't take place in an artificial environment? I contend that, just as hybrid swarms of plants in Nature can stabilize into new species, the process of prolonged hybridization can artificially create new species. I have been told that these hothouse plants...

[SOLVED] Calculate time evolution of Schrödinger wave equation Homework Statement At time t=0 particle is in state: \psi\left(x\right)=\sqrt{2}A\phi_{1}(x)+\frac{A}{\sqrt{2}}\phi_{2}(x)+A\phi_{3}(x) where \phi_{n}(x) are eigenfunctions of 1-D infinite potential well. a) Normalize...

I'm currently reading this article by Ken Miller on a plausible account of how the blood clotting mechanism in vertebrates might have evolved. There's some things I don't understand but which I hope someone here will explain to me: Here's the article...

Let me preface this by saying that economist Gregory Clark argues in "A Farewell To Alms" that one of the factors for the success of the industrial revolution was evolutionary in nature: disease killed off poorer members of the society and their position was taken over by sons of the wealthy who...

Might galaxies in filaments http://pil.phys.uniroma1.it/twiki/bin/view/Pil/GalaxyStructures" for spirals? An extented flattened curve means more DM further out; the original discovery route of DM.

Homework Statement At t=0, a given wavefunction is: \left\langle\theta,\phi|\psi(0)\right\rangle = \frac{\imath}{\sqrt{2}}(Y_{1,1}+Y_{1,-1}) Find \left\langle\theta,\phi|\psi(t)\right\rangle. Homework Equations \hat{U}(t)\left|\psi(0)\right\rangle =...

http://blog.wired.com/wiredscience/2007/12/evolution-battl.html Why? :confused: They had their butts kicked in Dover, PA. And have been proven wrong, that ID is not a science. So why do they persist?

I am reading a paper about self-similar.but this concept,evolution function,really troubled me.and i have seached wiki,but it didn't work.can anyone explain it wisely or provide a clue about it.

I got this link from someone: http://www.buzzle.com/editorials/10-27-2004-60892.asp I'm suspicious as no other science website has this as a main story, and it's strangely under the "editorial" directory. Give me your thoughts. Fact or fiction?

Homework Statement At t=0, the particle is in the eigenstate S_x , which corresponds to the eigenvalues -\hbar \over 2 The particle is in a magnetic field and its Hamiltonian is H=\frac{eB}{mc}S_z . Find the state at t>0. Homework Equations Eigenstate of the Sx is...

I believe I read the Black Death or Black Plague that effected Europe created a noticeable genetic bottlenecking in Europeans. HIV is still relatively new, but has anyone heard or have any ideas how HIV may effect human genetics and culture?

Okay I have a question. In micro-evolution, traits change among the same species, enough of these changes leads to macro-evolution. What is macro-evolution other than a different name and a series of small changes? A change big enough so that the new organism is no longer of the same species...

I've just finished reading Darwin's Origin of Species - A Biography and I realize I'm not much closer to understanding the subtleties of evolutionary theory. At least, I think I'm not. What Darwin brought to the world, while it rocked the foundations of biology, was not his alone. The concept of...

I was wondering if anyone knew anything about epidemic models which take into account the ability of a disease to mutate. Basically I’m curious if there are any existing models which could predict how a rapidly changing disease might affect the progression of an epidemic, or how slower...

This is a very general set of questions but sincere the same. If humans evolve to become telepathic, how would we have enough self control not to speak our private thoughts or accidentally insult others? Assuming we did gain enough self control during our evolution, what about the mentally...

can anyone recommend any good books or online articles that cover all the evidence in favor of evolution? I found this so far: http://www.talkorigins.org/faqs/comdesc/ it seems very long and detailed, considering I have very little background in biology. Is it a good site, nonetheless?

I realize that the understanding of physics and the perferred description or mathematical representation of our understanding evolves over time. So I have a feeling that the answer to my question is strongly a mix of history and physics. Please, when at all possible add some of the historical...

Personally i don't think evolution is stupid. I was watching a documentary with this title out of interest. You can watch the full documentary here: h**p://tv-links.co.uk/video/9/5566/8296/53218/76984# (If you copy and paste the link and replace the *s with ts it should work, if not...

Dear Zapper, I have read about evolution and agree with its explanations, atleast to the most part. My question is a bit deeper than the pressures of the environment. The universe is made up of all these tiny "particles" (lets keep the wave nature aside for the moment) and they formed atoms...

why doesn't life choose to keep living - is evolution stupid or crazy in that case? All life promotes its own kind by reproduction. Life is designed or has chosen to reinforce its existence so that it will continue. It is a mandatory priority for life to continue its existence. Why...

Homework Statement Can someone give me a general idea (I do not need and probably will not understand the rigorous mathematics) of how you can use the propagator equation \psi(x,t) = \int{U(x,t;x',t')\psi(x',t')dx'}, the equation for a Gaussian wave packet, \psi(x',0)= e^{i p_0...

I have no education in biology, nor am I going to get it, so this is just out of curiosity: as life fills the Earth and develops into more advanced forms, filling up the different niches - does evolution slow down because of "lack of room"?

I get the impression that all life on earth, including extinct life, goes back to the same single common source. Is this the general view? Or could life have started out independantly at different times and/or places. If so is there any evidence? Tony

Inspired by a book review of: The Origins of Virtue: Human Instincts and the Evolution of Cooperation by Matt Ridley Ridley suggests that altruism is instinctual. Cooperation and even self-sacrifice appear to Ridley to have evolved out of a need for and the instinct of survival of the species...

They have not found any major evolution is humans for nearly 30,000 years... I know it is a very slow process but 30,000 years is not enough for a little some thing to happen so we can prove that evolution is real?

Publications on the evolution of stars? Can anyone suggest a book that goes into detail on the evolution stars? I very much enjoyed as much as was discussed in Kip Thorne's Black Holes book and would like to read more about stars.

I have read before that grooming a mate evolved among the apes as a means of showing affection. All of the great apes existing today (with the exception of humans) include eating insects off of each other as part of grooming ritual. I wonder if kissing is the homo-sapien substitute for eating...

Hello I am a student in high school and my physics teacher is a complete idiot. He just gave us a project to draw the life cycle of stars without even teaching the class. I am completely lost. Can someone help me draw the life cycle of stars that includes small: G-yellow K-orange...

Can evolution theory work from a "plan" over generations ? I saw something rather interresting on TV one day, I believe it was National Geographic. or something like that. The TV program was about the historical evolution and development to animals living in the sea to then develop lunghs...

Hi all, I'm trying to understand someone's PhD thesis on the topic of variational surface evolution and its application in computer vision, and I'm having trouble working out how he evaluates some particular types of expressions involving the gradient. I think it'll be easier if I specify the...

What is time evolution? Is it a term only applicabe to matter waves or does it apply to other waves as well?

I am new to astronomy, though really interested in it Just read up on stellar evolution from multiple sources, but have some questions about it Let me summarize the theory of stellar evolution 1. gas clouds collapse due to multiple mechanisms, e.g. shock wave, collision of clouds... 2. the...

Hello, I haven't studied PDEs much yet, but checked out what the Navier Stokes equations are. I think I understood meaning of the terms in Navier Stokes equations, and what is their purpose in defining the time evolution of velocity of the fluid, but I couldn't see any conditions for the...

Here's a question that some of the biology people might be able to answer. What role does physics play in the study of evolutionary biology? When I was in college last year, a physics professor once came to my seminar class to give a talk on the role of physics in evolutionary biology...

Hi, (I think I started a thread similar to this earlier) I was wondering if anyone knows of any good websites or books or DVD's that focus on the evolution of organs and organ systems. That is, the point at which a group of cells stopped being a "blob" and started differentiating into organs...

Hello! I wanted to ask about the possible inflation era when considering the Big Bang model. Can someone explain me carefully but quite briefly what this inflation was? Thanks :)

Science has no idea of the mechanism. All that will be said is that it just happened and because it did there was life, which continued. There is no explanation beyond that. Of course there are other explanations outside science which account for this issue, which I believe, but I cannot talk...

Probably on the list of top 5 interesting (science) topics, of which I know next to nothing. Okay, natural selection, survival of the fittest and all that, but I'd like to have a better understanding, at least at the level of a layman. My last biology class was in school, about 7 years ago...