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Did you know dogs probably diverged from wolves before being domesticated by humans? The gray wolf (Canis lupus) exists today, and it was long assumed that modern dogs came directly from the gray wolf. However, DNA analysis suggests that modern dogs came from an ancestor (now extinct) of the gray wolf. There is some disagreement on when dogs diverged from wolves. Some evidence suggests it could have happened as long ago as 140,000 years. If so, dogs were definitely already a different species from the gray wolf when humans first began domesticating them. Regardless of whether the dog was already a separate species, this is a fascinating story. One thing we still aren't sure about is, did humans intentionally bring dogs (or wolves) into their camps, or did the dogs (or wolves) come to humans for easier access to food? We may never know whether it was the humans or the dogs that made the first move, but we do know the results significantly changed human history. DNA comparisons show that human domestication of the ancestors of modern dogs took place in eastern Asia, probably in China (note: another study suggests this may have happened in Europe). The dog was the first species humans domesticated (and the only large carnivore ever domesticated). After the relationship between humans and dogs became firmly established, dogs continued following humans, thus spreading across Asia and Europe, and eventually across the Bering Strait into North America and then into South America. What about the archaeological record? Well, there are dig sites, in which the dating is disputed by experts, showing remains of dogs and humans together as long ago as 30,000 years. Then there are numerous uncontested finds from about 14,000 years ago onward. The earliest undisputed find is in Bonn-Oberkassel, Germany—the remains of a dog that was clearly not a local wolf buried beside humans 14,200 years ago. As another example, in Israel there is a burial site with a woman actually holding a puppy. This site is dated at 12,000 years old. Obviously, since that time, dogs have been artificially bred into hundreds of different sizes, shapes, and colors, and they've had a huge influence on human civilization. Below is a gray wolf. Keep in mind, the wild ancestor of modern dogs is possibly an extinct ancestor of the gray wolf, not the gray wolf itself. Another way to say this is: modern dogs and gray wolves have a common ancestor. 
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With the recent rains we've had here, mushrooms have been popping up everywhere. I spotted these tiny fungus fruiting bodies while walking in the forest. These mushrooms are less than a centimeter across. I discovered that these are called "shaggy scarlet cup." Cool name. They are sometimes also called "pink fringed fairy cup," which I think is an even cooler name. Like all fungus fruiting bodies, these tiny mushrooms grow from the main part of the mushroom, an extensive series of microscopic filaments called hyphae (singular is hypha). The fruiting body grows from the hyphae and produces and disperses spores (the fungus version of seeds). Shaggy scarlet cups are usually found growing on decaying sticks or logs on the ground. Which means the fungus hyphae grow inside the stick or log, extracting nutrients from the decaying plant material. Why a cup shape instead of a typical dome-shaped fruiting body? Numerous species of cup fungi exist. Many of the typical cap-and-stem fungi release spores from the gills on the bottom of the cap, to be carried away by the wind. Cup fungi, on the other hand, produce spores on the surface of the upward-facing cup. Raindrops fall into the cup and splatter the spores out, dispersing them. Just another way to accomplish the same thing.  Photo Credit: Shaggy scarlet cup - Stan C. Smith Let’s say you buy a watermelon at the store, and it tastes so good that you want to extract the seeds and grow your own wonderful watermelons. But it’s a seedless watermelon, so you’re out of luck. Hmm… then how did the watermelon come into existence in the first place? Well, first of all, seedless watermelons actually do have seeds. You’ve seen them, those wimpy little white seed wannabes in the watermelon's flesh. You can just eat those seed wannabes without any problems because they do not have the hard black exterior shell that regular watermelon seeds have. In the flower stage in normal watermelons (with seeds), an egg cell in a female flower gets fertilized by pollen from a male flower, then the fertilized egg grows a fruit. Inside that developing fruit, the seeds are properly fertilized, which causes them to grow that hard shell (called the testa). But in seedless watermelons, the eggs are not properly fertilized. But why not? As with most sexually producing life forms, the egg contains one set of chromosomes and the pollen (or sperm) contains one set of chromosomes. After fertilization, the fertilized egg then has two sets of chromosomes. That’s the way things normally work. However, when growing seedless watermelons, the farmer treats the young watermelon plants with a chemical called colchicine, which causes the eggs in the flowers to develop two sets of chromosomes instead of only one. When those eggs get pollinated, they then have three sets of chromosomes. These can grow into big watermelon fruits, but the seeds in those particular watermelons are not genetically viable—they cannot get properly fertilized and therefore do not grow the hard, black testa. Those fruits are marketed as “seedless” watermelons. So, farmers still must plant regular watermelon seeds, then they treat the young plants with colchicine, and those plants grow "seedless" watermelons. I am of the opinion that food tastes better if you understand how it came to be. So, maybe your next slice of seedless watermelon will taste better than ever! Or, you could just stick with seeded watermelons because the seeds are fun to spit.  I noticed this long ago, and when hotels started putting these products in small, clear bottles, I even made the conclusion that the shampoo was made to look different from the conditioner simply to make it easier for people to grab the right bottle when they have soap in their eyes and they cannot read the ridiculously small print on the tiny bottles. This certainly makes sense to me. But, as is often the case, my conclusion was mostly wrong (although I would still bet plenty of people use this characteristic to choose the right bottle). Conditioner is opaque because it is emulsified. An emulsion is a mixture of two or more liquids that do not normally mix… they are unmixable (I just wanted to use that word). Conditioner is partly water and partly oil. But water and oil do not mix, so chemists have to use an emulsifier to make them mix. When the emulsifier makes the water and oil mix, the mixture becomes opaque. Now, shampoos on the other hand are partly water and partly a surfactant. A surfactant is something that reduces the surface tension of the liquid in which it is dissolved. In the case of shampoo, the surfactant acts as a detergent and a foaming agent (we all love our shampoo to foam up nicely, right?). Well, there is very little oil in shampoo, so there isn’t a need for an emulsifier, and therefore the shampoo remains transparent. But what about those shampoos that are opaque? Yes, there are some, and it is usually because they have much higher oil content (or they are shampoo and conditioner combined). Okay, seeing as how you are probably mesmerized by the exciting topic of shampoo, let’s look at a related question: why do we have to use shampoo before we use the conditioner? What if I’m feeling rebellious and want to reverse the order? Well, remember that shampoo has a surfactant that reduces surface tension, so the shampoo does not cling to your hair. Shampoo washes out completely, and therefore does not leave any conditioning coating to moisturize the hair. Conditioner clings to hair, because conditioners have positively charged ingredients that tend to adhere to hair, which is naturally negatively charged. This is why we use conditioner last—to leave a protective coating on the hair. So, now you can wash your hair in a very knowledgeable way. And if you can’t read the bottle because you don’t wear your glasses in the shower, use the clear stuff first, then the opaque stuff.  Trish and I recently spent some time in Washington state, exploring and visiting family. As we flew out of Seattle at the end of the trip, we got an excellent view of Mt. Rainier. This spectacular mountain is 14,411 feet (4,392 m) high, the highest mountain in the state. Perhaps one reason Rainier is so striking is that it stands alone, seemingly isolated from other significant peaks. This is because Mt. Rainier is a volcano, specifically a stratovolcanoe (built up of alternate layers of lava and ash), rather than being part of a mountain range with numerous peaks arranged in a line. Mt. Rainier is close to a million years old, though its current volcanic cone is about 500,000 years old. Historically, Rainier has been extremely active, with massive debris avalanches, volcanic mudflows, and eruptions. Rainier is considered to have a high probability of an eruption in the near future. That, combined with the fact that the mountain is near highly populated urban areas, makes Mt. Rainier one of the most dangerous volcanoes in the world. In 1980, Mt. St. Helens, which is Mt. Rainier's closest neighbor, created the largest eruption ever recorded in the continental United States. If Rainier erupts as powerfully as St. Helens did, the effects would be far worse. Why? Because Rainier is almost twice the size of St. Helens, it holds far more glacial ice (causing more volcanic mudslides), and Rainier is surrounded by vastly more heavily populated areas. Still, the mountain is an awesome sight.  Photo Credit: Mt. Rainier from plane: Stan C. Smith The cicadas seem to be winding down here, so I'm posting about them one more time. In Part 2, I discussed how periodical cicadas know when 13 (or 17) years have passed. Now, let's consider how—after the allotted number of years—they know how to emerge within just a few days of all their fellow cicadas. Seriously... one day the forest is silent, the next day the cicadas are emerging and singing to the whole world (well, singing to attract a mate anyway). How do they all get the memo at the same time? In my previous post, I stated that they emerge when the soil temperature reaches about 64ºF. True, but this can only be part of the story. Think about it... different areas of the soil reach 64º at significantly different times. Any area shaded by trees will be much slower to reach 64º. Deeper soil will also be much slower (cicada nymphs hang out underground for 13 or 17 years, but some of them are only a few inches deep, others are up to 18 inches deep). So, soil temperature alone does not explain how the cicadas emerge within a few days of each other. Based on numerous observations of real cicadas, mathematicians and biologists at Cambridge created a complex mathematical model of a huge underground cicada brood. This allowed them to tweak different variables, one at a time, to try to discover what would allow the cicadas to emerge together, as real cicadas do. After tweaking numerous variables, the scientists concluded the only thing that allowed the cicadas to emerge at the same time was if the insects were capable of communicating with each other underground. In the computer model, they gave the buried cicadas the ability to eavesdrop on the other buried cicadas near them. If the nearby cicadas (in slightly warmer soil) began making noise as they started climbing out of the soil, then the cicadas in slightly cooler soil were more likely to think, "Okay, I guess it's time to party!" (that's what I imagine cicadas are thinking after waiting 13 years underground for their time to emerge and finally mate). Anyway, this computer model could only produce simultaneous emergences (like we see in the real world) if the scientists gave their simulated cicadas the ability to communicate underground. Okay, well... we do not KNOW if real cicadas can communicate underground. Observing this will be difficult, but I'm sure biologists will come up with a way to do it. And I won't be surprised if the computer model turns out to be correct and underground cicadas really do have a way of talking to each other (maybe with clicking sounds?). The mysteries of nature are endless, are they not?  Photo Credit: 13-year cicada - Stan C. Smith How do 13-year cicadas know when it’s time to emerge? Much of Missouri is inundated right now with noisy 13-year cicadas (the 17-year cicadas are mostly to the north and east of Missouri). BIG QUESTION: How do the cicadas know 13 years have passed? Seriously, most of them emerge within a few weeks of each other, after living underground in isolated darkness and silence for exactly 13 years. It’s mind blowing. First, let’s look at WHY cicadas emerge all at once. This answer is simple—they do it to avoid being eaten before they have a chance to mate. Cicadas are not only defenseless, they are tasty and nutritious. Other animals snarf them up like a Las Vegas buffet. Well, cicadas need to emerge at the same time so that they can find each other as adults (so they can mate). The problem is, emerging at the same time creates a huge feeding frenzy among their predators. The solution? Emerge in such massive, incomprehensible numbers that predators cannot possibly eat them all. This is why we have periodical cicadas, a group of nine species of cicadas (out of more than 3,000 species worldwide... the others are annual cicadas) that time their emergence so that there are simply too many for predators to eat. This behavior is a rare and amazing adaptation. Okay, back to the question of how periodical cicadas know when exactly 13 (or 17) years have passed. As it turns out, we still don’t understand the whole story. We DO know that cicadas emerge when the soil temperature (at 12 to 18 inches deep) reaches about 64ºF in the spring. But that doesn’t explain why 13-year cicadas refuse to obey that urge every spring until the 13th year of their life. The leading hypothesis suggests cicadas are using tree chemistry to mark the years. For 13 (or 17) years, cicada nymphs live underground, slurping up the juices from tree roots. Each spring, when the trees produce flowers, the juices become rich with amino acids. The cicadas, of course, can detect this chemical change. Here’s proof: researchers took some 17-year cicadas that were 15 years old. The researchers altered their trees so the trees would flower twice in one year. As a result, the cicadas emerged a year early (at 16 years instead of 17 years). Proof that the cicadas count the number of times the trees flower, based on the surge of amino acids in the root juice. However, we still don’t know how the cicadas TALLY these annual events. Do they put little chalk marks on the wall of their burrow? Doubtful, but there has to be some explanation, right? Gotta love mysteries like this!  Photo Credit: 13-year cicada - Stan C. Smith |
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