Why Do Butterflies Have Such Vibrant Colors and Patterns?

Colours give butterflies camouflage, which helps them avoid hungry predators. It is an evolutionary process ( and the survival of the fittest).

 Growing butterflies are unable to move and in danger of being eaten or parasitized. So they take beautiful colour advantage: Adult butterflies also use color to their advantage—not only to blend in but also to warn.

For instance, the adult monarch sports a bright orange color and distinctive pattern, a red flag to potential predators that it's distasteful and toxic.

Another species called the viceroy has even evolved to mimic the monarch's appearance so that predators keep their distance.

 The blue morpho butterfly of the Central and South American rain forests. This insect's strikingly blue wing color "is used to communicate among butterflies, so they'll display it when they're courting or mating. Underneath the wing is a dull brown decorated with fantastic eyespots, which alarm and confuse predators.

As for how we humans perceive those brilliant butterfly colors, it depends. Some color we see is the insect's true pigment, and some is structural, or the way light reflects off a surface.

When you see blue, purple, or white on a butterfly, that's a structural color, while orange, yellow, and black are pigment.

The nanostructure of the chitin, or wing scale affects what light is reflected and how it's reflected.

This is what makes butterfly wings iridescent—the quality that makes them change color according to the angle from which you look at them.

The diet of some caterpillars affect their colours: paper kite caterpillars eat to turn the chrysalis golden.

The diet of the caterpillar doesn't affect the hue of the paper kite chrysalis, though it does affect the chrysalis color of other species.

Plant-derived chemicals called flavonoids—which differ in leaves, flowers, and seeds—can influence chrysalis color.

The zebra swallowtail, for example, feeds on the leaves of plants of the  Asimina family—and has a leaf-green chrysalis.

The poet also says, producing music in a flute is a wonderment. 

Is it? We know how music is produced in a flute. With the help of flute acoustics. 

The flutist blows a rapid jet of air across the embouchure hole. The pressure inside the player's mouth is above atmospheric (typically a few tens of kPa: enough to support a few tens of cm height difference in a water manometer). The work done to accelerate the air in this jet is the source of power input to the instrument. The player provides power continuously: in a useful analogy with electricity, it is like DC electrical power. Sound, however, requires an oscillating motion or air flow (like AC electricity). In the flute, the air jet, in cooperation with the resonances in the air in the instrument, produces an oscillating component of the flow. Once the air in the flute is vibrating, some of the energy is radiated as sound out of the end and any open holes. A much greater amount of energy is lost as a sort of friction (viscous loss) with the wall. In a sustained note, this energy is replaced by energy put in by the player. The column of air in the flute vibrates much more easily at some frequencies than at others (i.e. it resonates at certain frequencies). These resonances largely determine the playing frequency and thus the pitch, and the player in effect chooses the desired set of resonances by choosing a suitable combination of keys. In this essay, we look at these effects one by one.

https://newt.phys.unsw.edu.au/jw/fluteacoustics.html

Koel ( birds) singing without a teacher is a wonder.

 NO, not at all! We know how this happens. 

Birds learn to sing in much the same way humans learn to talk: by listening to, and then imitating, the vocal sounds of their elders. Of course, those sounds rarely come out right the first time, but a fledgling's sense of hearing can tell her just how off the mark she is.  If a note is too low, she’ll know to whistle it higher next time, and that feedback helps birds (and us) learn how to communicate.

Scientists have conducted experiments to understand how birds learn to sing. 

For the study, scientists at Emory University and the University of California, San Francisco altered the auditory feedback of six male Bengalese finches by playing back, in real-time, an altered version of the birds’ own sounds.

During several two-week experiments, the scientists used audio processing equipment to shift the pitch of the finches’ vocal sounds by a set amount. In some of the experiments, the scientists shifted the pitch down by just a fraction of a tone–if the birds sang a C, for example, the tiny headphones over their ears would play back a tone halfway between a C and a C flat.

In other experiments, the pitch-shift was much larger, so that the birds might sing a C and hear, through its auditory feedback, a B:

Surprisingly, the researchers found that the finches made larger adjustments to their singing when they listened to slightly altered versions of themselves than when the pitch shift was large:

As the chart shows, when the finches heard their singing downshifted by just 1/2 semitone, they up-shifted their voices by almost the same amount to correct for the imposed error. But when the alteration was much greater, the birds made little adjustment to their singing.

In addition, the researchers detected a mathematical relationship between the birds’ songs and their ability to correct for errors: The more the musical range of the altered songs overlapped the range of the finches’ original tunes, the more the birds adjusted their singing to compensate for the shift:

But when the researchers altered the pitch so much that there was no overlap between the ranges of the original and processed songs, the birds did not learn to adjust their own tunes.

The upshot is the more minor the mistake, the better a bird is at correcting it. Thus birds can fine-tune their vocal instruments until they become the superb singers we know them to be.

https://www.popsci.com/science/article/2012-12/how-birds-learn-sing....

And the beauty of a woman is a wonder. Really?

The old adage, “Beauty is in the eye of the beholder, " may be true, a universal definition of attractive cannot be denied. Which characteristics must a person possess to be considered beautiful or attractive?

The  criteria for beauty according to scientists and researchers comes down to symmetry and health. A beautiful face exhibits perfect symmetry. One side mirrors the other. Think proportionate when it comes to the body and face. The eyes should be proportionate to the head and face.

Scientists are also learning that there may be a practical side to our obsession with beauty. A pretty face may belong to a healthier person. Or it may simply be easier for our brains to process.

Males prefer a shapely feminine body with correct bust-to-waist-to-hip ratio.

But conditioning of mind too makes you look at beauty in a different way. Beauty is considered differently in different cultures. Are we born with a preference for certain kinds of faces? Or is it just something that people learn, without realizing it?

Scientific studies suggest that people prefer pretty faces very early in life. By the time researchers test infants, they already have experience with faces. That experience can make a difference. Research conducted  found that babies’ brains are better at processing faces from their own people. So infants quickly come to prefer these faces. It’s well-known in psychology that familiar things are more attractive. Perhaps average faces are more attractive because they seem more familiar.

Research findings show how biology and the environment work together to shape our values.

On the whole a healthy woman is considered as beautiful because healthiness is a sign of reproductive capabilities.

Research shows that people with more symmetrical faces don’t just look nice. They also tend to be healthier than asymmetrical people. Genes provide the instructions for how a cell is to perform. All people have the same number of genes. But people with more average faces tend to have a greater diversity in the genes they are born with. And that, research has shown, can lead to a stronger immune system and better health.

Scientists have found similar links between “beauty” and health in other animals too. This preference for beauty may help us find healthy mates.

https://www.sciencenewsforstudents.org/article/what-makes-pretty-face