On the discovery channel we were watching said the moon was twice as big in the sky when the dinosaurs were alive. How much higher/lower would high tide and low tide be?
Assuming you mean twice the angular size, the moons gravity would be four times greater so I would expect around four times the tidal effect. At that magnitude it would be no wonder that so many life forms would adapt to the tides.
Coffee isn't calorie-free -- nothing containing organic molecules truly can be zero-calorie.
If you're talking about mold growing on coffee beans or grounds, as JoeP points out, they'd have oils, proteins, and carbohydrates that could serve as food for mold, even after having been roasted.
An 8-ounce cup of black coffee contains about 2 Calories of food energy. That's not a lot, of course, but it's enough to support a mold colony.
***
Incidentally, I did not commit a typo in spelling "Calorie" with a capital "C" there. To a chemist, a calorie (lowercase "c") is the amount of energy needed to raise the temperature of one gram of water by one degree Celsius.
But a "food calorie" (properly, written with a capital "C", to distinguish from a "regular" calorie) is actually 1,000 calories (a kilocalorie). So a cup of coffee actually contains about 2,000 calories. That might not be enough to keep a person going for very long, but it's more than sufficient to keep a colony of mold going for some time.
I'm guessing that food companies insist on using kilocalories and calling them "Calories" because it would be cumbersome (and perhaps a bit embarrassing) to say that a Big Mac (for example) contains some 576,000 calories (and that's without cheese).
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
I was referring to when I forget that I made a pot of coffee on Friday, and when I come in to work on Monday there are cool mold colonies growing in the grounds in the filter basket. Every time I'm like, "WHAT ARE YOU EATING?!" because I love coffee specifically for it's non-calorie-having property. I guess mold just needs a lot less energy than I do.
On the discovery channel we were watching said the moon was twice as big in the sky when the dinosaurs were alive. How much higher/lower would high tide and low tide be?
Remember, this is the same channel that features such interesting specials as "the science of star wars"... Sounds pretty fishy to me.
On the discovery channel we were watching said the moon was twice as big in the sky when the dinosaurs were alive. How much higher/lower would high tide and low tide be?
Remember, this is the same channel that features such interesting specials as "the science of star wars"... Sounds pretty fishy to me.
The average distance between the Earth and Moon is about 384,000 kilometers at present. The distance between them increases by 3.8 centimeters (0.000038 kilometers) per year.
Assuming this rate of change has remained more or less constant, then the distance between the Earth and Moon has increased by a whopping 3,800 kilometers during the past 100 million years. (100 million years would put us well back into the time of the dinosaurs.) That's a 1% change in distance, approximately -- hardly enough to be noticed, I should think.
Currently, at closest approach (perigee), the Moon is 363,104 kilometers from the Earth; at its furthest (apogee), it's 405,696 kilometers away. In other words, during a single month, its distance from us changes more than the average distance has in 100,000,000 years.
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
I'm guessing that food companies insist on using kilocalories and calling them "Calories" because it would be cumbersome (and perhaps a bit embarrassing) to say that a Big Mac (for example) contains some 576,000 calories (and that's without cheese).
We have large banana spiders (golden silk spiders) on either side of our porch entry, about 5 feet apart. They are about the same size, with the same sized webs, definitely same species, but they behave so differently with regards to feeding and web maintenance.
The clean one (called S for my mother) works on her web several times a day seemingly for maintenance, and repairs it anytime a bug, wind, rain, etc. wrecks it. The other day she was frantic as it rained all day and blew in leaves and such. I've never seen a spider work so hard. When she catches something she goes to where it is, wraps it up only enough to immobilize it, eats it right there, then cuts the carcass from her web and repairs the hole.
The other one (B for me ) never repairs holes, she just throws up more anchor lines. If she gets a bug, she goes to where it is, wraps it up really tight, hooks a towline to it, drags it to the top and hooks it there, eats it, then leaves the carcass...they are all lined up and some have been there over a month. The bottom of her web is littered with legs, wings, parts of her old self from molting, blown in debris, etc.
Seems weird to me that they can have personalities.
I forgot to answer this question -- sorry!
Even for very "simple" animals, their behavior is largely determined by what they've learned, and so even two genetically-identical animals would be expected to have (slightly) different behaviors -- "personalities," if you will.
As an aside, most zoologists raise their hackles at terms like "lower animals." Every extant animal species can trace its ancestry back to the same common animal ancestor, and so it's both factually-incorrect and a serious misunderstanding of how evolution works to say that one species is "higher" or "lower" than another. Obviously, some lineages have undergone much less morphological change over the eons than have others, but it's a mistake to think that means they're in any way "less evolved" or any such thing.
Obviously, some animals have more complex bodies than others, and some have more complex brains than others and are, therefore, capable of more complex behaviors. But it's only our (understandable) bias as complex-bodied and intelligent animals that makes us think that animals like ourselves are in any way "higher" than are clams or planaria or whatnot.
Anyway, since even very simple animals can learn, and will therefore be influenced by their environments to some extent, inevitably, there will be some behavioral differences between different animals of the same species -- even if they're very simple-brained animals that rely almost entirely on "instinct."
But there's an interesting twist. A few years ago, some researchers in Animal Behavior published an interesting study showing that there's considerable evidence that there is a genetic predisposition for two basic behavioral types in an astonishing variety of animal species. What they found was that, in a very wide range of species -- from shrimps to various fishes -- most individuals could be divided into two basic behavioral categories, and that these behavioral categories were genetically based.
Some individuals tend to be "fearless" and "outgoing" -- prone to explore their environments, to try different kinds of potential foods, and so forth. The price to pay is that this is a risky strategy; such individuals are more likely to be killed by predators, to be poisoned, etc. On the other hand, if such an individual happens upon a really good food source or place to live, this strategy pays off handsomely.
Other individuals of the same species tend to be much more "shy" -- they tend to be much less willing to explore their environments, try new types of food, etc. Naturally, these individuals are less likely to be poisoned or to be captured by predators, but they're also less likely to find new living spaces or food sources.
Of course, one can't help but notice that some human infants are much more outgoing than others, so it's by no means unlikely that similar genes influence human behavior. One important difference, of course, is that human behavior is far more flexible and labile than is the behavior of most non-human species.
Regardless, the short answer is that, yes, there can be and often are distinct "personality" differences -- even in animals with nervous systems as simple as are those of spiders.
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
But there's an interesting twist. A few years ago, some researchers in Animal Behavior published an interesting study showing that there's considerable evidence that there is a genetic predisposition for two basic behavioral types in an astonishing variety of animal species. ...
Does this say that a single individual's genome encodes this predisposition - so they would have descendants with a mix of the types? (Like having male and female children.)
Or that it's a characteristic of a population that's preserved by selection, neither have a survival advantage over the other?
But there's an interesting twist. A few years ago, some researchers in Animal Behavior published an interesting study showing that there's considerable evidence that there is a genetic predisposition for two basic behavioral types in an astonishing variety of animal species. ...
Does this say that a single individual's genome encodes this predisposition - so they would have descendants with a mix of the types? (Like having male and female children.)
I'm not entirely certain waht you mean, since these aren't mutually-exclusive concepts. To my knowledge, no one has worked out the genetics of this yet, but presumably there are some genes that promote "bold" behavior and others that promote "shy" behavior.
Conceivably, it could be as simple as a single gene locus being responsible for predisposing an individual toward "shy" or "bold" behavior. But again, it's best to keep in mind that there's no such thing as purely "genetically-determined" behavior; all behavioral traits have both genetic and environmental components. (By the same token, there's no such thing as purely "environmentally-determined" behavior.)
If it turned out to be a single genetic locus with only two variant alleles, the genetics would be ridiculously simple -- any given individual would either inherit 2 genes for "shyness," 2 genes for "boldness," or one gene for each.
The reality is that the genetics is almost certainly more complex than that. Furthermore, it's quite likely that the genetics varies in different taxa.
Regardless, even if a given parent is homozygous for the trait in question, in a sexually-reproducing species, every child inherits genes from two different parents. So just as a given female can have both male and female children (even though she's homozygous for the sex-determining genes), a given individual could have both "shy" and "bold" offspring. Indeed, it's often the case that a single brood will contain both "shy" and "bold" individuals.
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Or that it's a characteristic of a population that's preserved by selection, neither have a survival advantage over the other?
This is almost-certainly what's known as an "evolutionarily stable strategy." There are lots of traits (both physical traits and behavioral traits) in which there are two or more stable, genetically-determined variants. ("Genetically-determined" in the sense that there are 2 or more different variant genes that promote these traits.) Such a population is said to be polymorphic.
In an ESS, polymorphism is maintained because each of the variants is advantageous, but for different reasons. This is almost certainly the case with "shy" vs. "bold" behavioral predispositions. The "shy" strategy is a more conservative strategy, and in most instances, "shy" individuals will survive and reproduce better than "bold" individuals (who will probably have higher death rates). But every now and again, a "bold" individual will hit the jackpot, so to speak, and that lucky individual (who happens upon a particularly good food source, or a particularly good place to live, or whatever) will probably have lots of offspring.
So, on average, "shy" and "bold" individuals have equal numbers of surviving offspring, even though the variability in reproductive output is much higher for the "bold" individuals. (Note: this does not imply that the ratio of the two different phenotypes will be 50:50. In fact, it almost-certainly will not.)
The population dynamics are usually much more complicated than that, actually. I'll try to illustrate how an ESS works by using a species with which I'm very familiar, the Eastern Screech Owl (Megascops asio).
In this species, there are two stable color morphs, "rufous" (red-brown) and "gray" (gray-brown). Owls of the two different morphs look so different that they were long considered to be different species, until it was shown that rufous and gray owls often interbreed, and that rufous and gray chicks often occur in the same cluch.
The rufous morph seems to be specialized for life in good environments. Rufous owls have higher metabolic rates than do gray owls, and appear to produce more offspring than do gray owls, on average -- assuming ideal conditions.
By contrast, gray owls have lower metabolic rates on average, can supplement their energy stores by basking in the Sun and absorbing solar energy (something that the rufous owls don't do nearly as well), require less food, and are generally well-suited to relatively poor environmental conditions.
In relatively good areas, where food and shelter are abundant, where winter temperatures are moderate and there's little snow cover, rufous owls are much more common than are gray owls. (Screech owls, unlike some owl species, cannot hunt by sound alone, and so cannot hunt for prey burrowing under snow. So snow cover severely impacts their ability to find prey.)
In relatively poor areas, such as where there is a lot of snow cover during the winter, or where there is very little suitable shelter, gray owls are much more common than are rufous owls. What's more, the rufous/gray ratio fluctuates from year to year. For example, if it's an unusually cold and snowy winter, rufous owls have much higher mortality rates than do gray owls. By contrast, if it's a warm and snow-free winter followed by a spring and summer in which food is abundant, the rufous owls simply out-reproduce the gray ones, it seems.
Anyway, this is an example of an ESS. Each color morph in this polymorphic species is optimally-adapted for different environmental conditions. Not only does this allow the species to occupy a wider range of environments than would otherwise be possible (or at least likely), but it also reduces the probability that changing environmental conditions will render the species extinct.
Polymorphism in physical and/or behavioral traits is actually very common in plants and animals, and in many cases, experiments have shown that this polymorphism is very definitely being maintained by natural selection. Indeed, the existence of distinct "male" and "female" phenotypes in most plant and animal species is a good example. The evolutionary dynamics of male/female sex ratios are far more complicated than most people would ever guess.
Quote:
Originally Posted by JoeP
... Is a genome a property of an individual or a population?
All of an individual's genes make up its genome. All the genes within a population of organisms make up its gene pool.
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
Didn't mean to be offensive of course, I meant "simple brained" when I said lower
There's an interesting explanation for why people (including many biologists, who really should know better) often use "higher" and "lower" to refer to various organisms. It's rooted in the pre-evolutionary concept known as the "Great Chain of Being."
Long before Darwin, people noted that certain groups of plants and animals shared characteristics, and appeared to be related somehow. It was also apparent that some organisms were simpler (in various ways) than others. This led to the notion of the "Scala Naturae," the "Great Chain of Being," or the "Ladder of Life." According to this notion, virtually all things could be located on a scale, ranging from the "least perfect" on the bottom to the "most perfect" on the top.
In most conceptions of the scala naturae, rocks represented the lower-most portion of the scale. Very "simple" plants such as liverworts would occupy a higher position. More "advanced" plants such as ferns would occupy a still-higher position. "Higher" plants, such as fruit-bearing plants would occupy a still-higher position.
"Lower" animals would occupy a higher position on the scala naturae than any plants, and "higher" animals would occupy an even higher position, naturally. Humans, of course, occupied a higher position than any other animals, and angels were assumed to occupy an even higher position. The highest position of all, naturally, was occupied by God.
Within each division, it was sometimes convenient to make subdivisions. For example, it was usually assumed that Africans were at the lowest portion of the Human division -- just above the apes. European Whites, naturally, were generally assumed to occupy the highest portion of the Human division -- just below the angels.
Anyway, that notion -- that living (and non-living) things existed on a continuum of "least perfect" (lowest) to "most perfect" (highest) -- was, of course, completely opposed to an evolutionary perspective. It was, nonetheless a very firmly-established notion in Western culture -- so much so that the very language used to describe living (and non-living) things reflected that belief.
Darwin himself warned that scientists shouldn't use such terms when referring to living things, since it represented a discredited and fundamentally-mistaken view of the relationships between living things. Even so, he himself often referred to "higher" and "lower" plants/animals in his writings, which illustrates just how deeply the concept was embedded in the culture and language.
Of course, one frequently hears people referring to "higher" and "lower" organisms even today, though I'd bet that not one person in a thousand knows what those terms actually mean.
And like I said, I've even heard biologists making casual reference to "higher" and "lower" organisms -- and they, of all people, should understand that this is a vestige of a fundamentally-mistaken way of viewing the relationships between living things. Old habits die hard, though.
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
So, on average, "shy" and "bold" individuals have equal numbers of surviving offspring, even though the variability in reproductive output is much higher for the "bold" individuals. (Note: this does not imply that the ratio of the two different phenotypes will be 50:50. In fact, it almost-certainly will not.)
...
All of an individual's genes make up its genome. All the genes within a population of organisms make up its gene pool.
And now clean spider has abandoned her web. I can find little information on the banana spider life cycle. Like, for example, where they lay their eggs (not in their webs like another seasonal spider I was familiar with in the desert, Black Widows), nor do any locals seem to know where and how they live in the winter.
They show up in late June, and are gone by October usually. We hosted the "nursery" last year, with about 30 young spiders that dispersed when they got big. No idea where they came from.
Your spiders are almost-certainly Nephila clavipes, also known as Golden Orb Weavers. (There's an unrelated South American species that's also commonly called the "Banana Spider.")
Nephila clavipes is quite common in the southeastern U.S.
An adult female Nephila clavipes.
The females lay their eggs in the late Summer or early Fall, wrapping them in golden silk. Usually, she will hide them in a nearby tree or under the eaves of a house -- that sort of place. She'll live for another few weeks, then die.
The eggs will probably hatch next Spring, though they might hatch in the late Fall if it's warm enough. In any event, the tiny spiderlings will prey on smaller arthropods and won't grow large-enough to be noticed until the Summer, which is why they seem to almost appear out of nowhere at that time of year. Once the females grow large-enough, they'll start building prominent and easily-visible webs. Males are much smaller than females, and a male can often be found hanging out in a corner of a female's web.
A female (below), with an attending male.
Cheers,
Michael
__________________
“The greatest way to live with honor in this world is to be what we pretend to be.”
Re: Stupid Science Questions Thread
Every time I'm like, "WHAT ARE YOU EATING?!" because I love coffee specifically for it's non-calorie-having property. I guess mold just needs a lot less energy than I do.
) never repairs holes, she just throws up more anchor lines. If she gets a bug, she goes to where it is, wraps it up really tight, hooks a towline to it, drags it to the top and hooks it there, eats it, then leaves the carcass...they are all lined up and some have been there over a month. The bottom of her web is littered with legs, wings, parts of her old self from molting, blown in debris, etc.
provides many examples of human beings with ... simpler brains.
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