Apparently, there is an advantage to having 6 legs in the insect world. What is that advantage, if anything? Why would such an advantage exist for insects, but not for other, larger land animals?  What do those middle legs do that the front and hind legs cannot, if anything? Are they really essential, or do they just generate more muscle power?
If a trait would be advantageous to an organism then why hasn't it evolved yet?  Conversely, if a trait is not advantageous or mildly disadvantageous, why does it exist?  In other words why does evolution not make the organism more "perfect"?    This is a general question that would be applicable for any kind of trait. Please keep the answers precise and scientific.   Read this meta post for more information:
How to take a screenshot of a whole desktop with app menu selection? Comparing and contrasting, p-values, significance levels and type I error I was wondering if anybody could give a concise rundown as to the definitions and uses of p-values, significance level and type I error.  I understand that p-values are defined as "the probability of obtaining a test statistic at least as extreme as the one we actually observed", while a significance level is just an arbitrary cutoff value to gauge if the p-value is significant or not. Type I error is the error of rejected a null hypothesis that was true. However, I am unsure regarding the difference between significance level and the type I error, are they not the same concept?  For example, assume a very simple experiment where I flip a coin 1000 times and count the number of times it lands on 'heads'. My null hypothesis, H0, is that heads = 500 (unbiased coin). I then set my significance level at alpha = 0.05.  I flip the coin 1000 times and then I calculate the p-value, if the p-value is > 0.05 then I fail to reject the null hypothesis and if the p-value is &lt; 0.05 then I reject the null hypothesis.  Now if I did this experiment repeatedly, each time calculating the p-value and either rejecting or failing to reject the null hypothesis and keeping a count of how many I rejected/failed to reject, then I would end up rejecting 5% of null hypotheses which were in actuality true, is that correct? This is the definition of type I error. Therefore, the significance level in Fisher significance testing is essentially the type I error from Neyman-Pearson hypothesis testing if you performed repeated experiments.  Now as for p-values, if I had gotten a p-value of 0.06 from my last experiment and I did multiple experiments and counted all the ones that I got a p-value from 0 to 0.06, then would I also not have a 6% chance of rejecting a true null hypothesis? Why would I need a firewall if my server is well configured? JSON.parse: unexpected character Blog showing up as mobile, won't exit Stack Exchange blog is showing me the mobile site and won't let me exit on Chrome 21. Could someone take a look? Thanks. Edit I noticed it was with the special query string, that I can't exit it. How can I use the compositor on the result of the sequencer? I recently ran a renderfarm on a file with some compositing setup, but I forgot to set the composite output back to the Composite node instead of the Viewer I was temporarily using. Since the node setup didn't require anything besides the image data (i.e., no Z-buffer, object IDs, etc.) I figured that I could just run the compositor on each frame individually. However, this proved to be somewhwat difficult.  It seems that the sequencer is run after the compositor (despite their non-exclusivity in the Post Processing panel), so my idea to use an image strip in the sequencer for all the images that I already rendered didn't work&mdash;the render just copied the images into a new directory.  The Movie Clip node doesn't seem to accept an image strip as input, either, so that was not an option.  What I ended up doing was sequencing the animation to a movie file, then piping that into the Movie Clip node in the compositor. However, this required extra time, extra storage, and it rendered the default scene every frame before compositing, only to ignore the result.  Is there a way to use Blender's compositor either directly on an image sequence, or in conjunction with the video sequencer? dynamically change UIKeyboards return key What techniques have been used to repeat geometry or other detail to the infinite horizon? When I composed my     I would have liked to have the camera pitch up enough to show the horizon, except I didn't have enough geometry to extend the cobblestone street and the sidewalk all the way to infinity (mostly because that would require infinite stuff).  Even in that shot it is clear that I need to widen the "sidewalk" to cover up the "sky"box.    Contrast with     where the ray tracer can use the procedurally replicated geometry.   is a failed attempt at faking out the horizon, even with low detail.  It fails because lighting's interaction with the geometry gives it away.  Some techniques that prevent you from having to deal with infinity include   put the scene in a box (usually a room) put the scene in a canyon (which is just a box without a top so you can see the relatively featureless sky) route the road into a tunnel, or around a corner and hide the horizon with other geometry (which is really just a variant on the canyon). have no detail on the ground at all (flat color or gradient)   Those are all dodging the question of interest to me:  What techniques have people used in blender to fake various kinds of detail repeating into the distance (instead of just obstructing the view of infinity)? How are unmarketable market orders (other side of the order book is empty) matched with incoming orders? Isekai manga where the mc is reincarnated through his own magic The MC reincarnated himself through his own magic after his party defeated the demon king. Before he used his magic to do so, he took the daughter from the demon king and traveled with her over the world. After he used his reincarnation magic he was born in a noble family where the daughter of the demon king is now working as a maid in this family. He also has an older/younger (not sure) brother. Through his knowledge he starts his training of body, swordsmanship and magic as a baby. Years later his brother wants to play with him but he denies him every time. But one day he accepts it to play tag. His brother can't catch him. After that, he requests from the mc to teach him his magic. He denied again, but made an offer. Only when he can catch him, would he teach him his magic. I hope I'm not mixing up different mangas. What is "root" and how can I become it? When I ran a command, I got the following error:     You need to be root to perform this command.   What is root and how can I become it? Column validation for US phone number format Ever since I upgraded to 13.10, the software updater does not show all the available updates. Some will appear and can be installed just fine, but once it claims that all software is up to date, using sudo apt-get upgrade shows that there are still more packages waiting to be updated. I can update them via the command line, but that only solves things temporarily. I'm not sure why some show up and others don't. How can I make Update Manager update all packages?  Update-manager shows this:    But apt-get shows this:   Thanks! Can a hotel kick you out if you let an unregistered guest share a room with you? We are going to an event and because of this event all hotels are fully booked. Now a friend wants to join us, but can't find accommodation. We are okay with him crashing in our hotel room, either on the couch or on a self-inflatable mattress. We have done this in the past where we secretly sneaked the "guest" in.   It is not that we don't want to pay the tourist tax, it is that when ask and the hotel says no, we can't sneak him in, because we drew attention to ourself. In many hotels you can just order another bed, but there are also a lot that don't have that service.   I don't have any ethical problems with my behavior of secretly hosting a guest. I did pay for the room. I don't like being sneaky about it, since again I do pay for the hotel room. Also if I have to choose between sneaking someone in the room to crash on the couch or let him/her sleep on bench in the park. I opt for the first.   Am I just worrying to much and will being honest about it in the end be acceptable to most if not all hotels? Prove that $x^{2} \equiv -1 \pmod p$ has no solutions if prime $p \equiv 3 \pmod 4$. What is the probability that a person is the second person to roll a 6 for the first time? Suppose $A$, $B$, and $C$ roll a die in turns. What is the probability that $A$ is the second person to roll a $6$ for the first time? Why does change in speed of a wave make it refract? When a light wave enters a medium with a higher refractive index (e.g. from air to standard glass) and its speed decreases, why does that make it refract/bend?  I understand that wavelength decreases and frequency stays the same and therefore its speed decreases, but I can't find anywhere whatsoever why the speed decrease cause the wave to refract. So could someone please explain this? Penalized methods for categorical data: combining levels in a factor Is there a continuous function such that $\int_0^{\infty} f(x)dx$ converges, yet $\lim_{x\rightarrow \infty}f(x) \ne 0$? Will I be demoted to a lower league in Starcraft 2 if I don't play? I've just been promoted from platinum league to diamond and master pretty fast (in 4 vs 4). This was totally amazing for me but I'm afraid I will be demoted again to a lower league as fast as I came higher.   If I don't play any 4 vs 4 anymore, will they demote me to a lower league automatically or do they only do so, if I play?