Category: Evolution

No, not the “flowers as symbols of love” trope.

daylilyFlowers are quite literally the sex organs of plants. A complete flower has male parts (stamens) and female parts (pistils.) In the daylily photo the stamens are the thin stalks (filaments) ending in the fluffy-looking things (anthers), while the part of the pistil visible is the slightly curved stalk below them.

The anthers release pollen (analogous to sperm cells in animals) which, when if falls on the sticky end of the pistil (the stigma) grows a tube to the ovaries, fertilizing the ovules within it, which can then grow into seeds. Those notorious birds and bees often assist in the process by transporting the pollen from one flower to another. In fact the colors and smells of flowers probably evolved to lure these pollinators, as did the nectar our honeybees make into honey.

The ovary, which can be above or below the base of the petals, is what grows into the fruit—the sometimes-edible part surrounding the seeds. As it happens, the ovary in the daylily is above the petal base and hidden by the petals; that on the squash we’ll discuss later is below the petal base.

female zucchini flower

Female zucchini flower, showing small squash as stem. Male flower stem visible in background.

Now plant sex is a good deal more varied than animal sex. Some plants have both stamens and pistil in the same flower, like the daylily. In extreme cases, the flower doesn’t even open, and the plant pollinates itself, but this is rare and seen mostly in some members of the legume and viola families. At the other extreme, the whole plant is male or female, and two plants are needed for pollination. Some plants cannot be fertilized by their own pollen, and two varieties must be planted in order for them to set fruit. And in some there are two distinct kinds of flower, male and female, on the same plant. The male flower has stamens and produces pollen, but never produces seed or fruit. The female flower is the only one that produces the fruit.

If you’ve been reading this blog, you’ve no doubt noticed that I’ve been referring to male and female squash flowers. I grow zucchini, and they produce male flowers first, and then female flowers. Only the female flowers actually produce squash, so those are the ones I watch for.

How do I tell? Well, I could look inside the flowers, which are large enough to see the difference. But with zucchini, there’s a simpler way. In squash, the ovary is below the base of the petals, which means that if you look at the “stem” of a female flower, most of what you see is what will grow into a squash. Slender, smooth stems indicate male flowers (lots of those right now) which will never produce squash themselves. Fat stems, or yellow ones in the case of yellow zucchini, indicate female flowers and squash to come.

I don’t think the squash pictured will be ready to eat before next week, though they can grow remarkably fast from this size – the photo was taken June 28. But I fully expect to have my first zucchini by the end of next week. (I’d better remember to add parmesan cheese to the grocery list, as I prefer zucchini braised in olive oil with oregano and sprinkled with cheese and garlic salt.)

DVD CoverThis disc, although it has a copyright date of 2008, is a collection of TV programs originally aired between 2003 and 2008. Thus none are really up to date.

“The Mystery Dinosaur,” from 2006, deals with the discovery of  “Jane.” This fossil has been variously identified as a Nanotyrannus and a juvenile Tyrannosaurus Rex. The program is primarily about the argument, which could date it, but as far as I can tell, the argument has never been resolved. Thus the program is still fairly current, though it is more science than entertainment.

“Dinosaurs: Return to Life” deals with the observations that the differences between dinosaurs and birds appear to be due to a relatively small number of mutations. Could birds be “reverse bioengineered” to produce something like dinosaurs? Would we really want to?

The four-program series “Dinosaur Planet” first aired in 2003, and unlike the rest of the programs in this set, it is definitely intended to be entertainment. Each of the four episodes focuses on one or two individual dinosaurs and follows them through a period of their lives. Each episode also covers something that is important or intriguing in the fossil record, and links back to that record. Thus “White Tip’s Journey,” featuring a Velociraptor,  suggests one explanation for the famed (real) fossil of a Velociraptor locked in a death struggle with a Protoceratops.

“Alpha’s Egg,” featuring the large sauropod Saltasaurus and the medium-sized predator Aucasaurus,  is based on the discovery of  a Saltasaurus nesting ground,  fossilized in Patagonia.

Pod of “Pod’s Travels” is based on a Pyroraptor,  a European raptor genus. The episode includes the natural hazards (earthquake, tsunami) that made occasional travel between the islands that made up Europe 80 million years ago possible. The focus of the program is on the dwarfing effect that islands tend to have on species. Pod is a Gulliver among Lilliputians when a tidal wave sweeps him to a much smaller island.

“Little Das’ Hunt” follows a juvenile Daspletosaurus  (an earlier close relative of Tyrannosaurus Rex) learning to hunt, and a herd of Maiasaura. The episode is based on a group of Daspletosaurus and Maiasaura found fossilized together in Montana, but the evidence for the kind of pack behavior shown in the episode is scanty and controversial.

Obviously there is a good deal of imagination going into the behavior, color, feathers or lack of them, musculature and behavior of all of these dinosaurs. Here I want to mention three, because they struck me so strongly.

The first is the underline of the creatures portrayed.  Theropod dinosaurs did indeed have a bone jutting back from the pelvis. However, the velociraptors are shown as having this bone stick out of the body, covered by a narrow wedge of tissue. It seems to me that this arrangement would be very susceptible to breakage, and that evolution would have reduced the length of the bone fairly fast. It makes much more sense that the tail and the posterior part of the belly were much deeper, with the projection buried in muscle. In fact a mummified hadrosaur had exactly this conformation, with a tail much deeper than anyone expected. Why not Velociraptor?

Second is the behavior of prey dinosaurs. Granted they didn’t have much brain, but instinct is also guided by evolution. Threatening a predator with teeth adapted to munching relatively soft leaves, and exposing the vulnerable neck in the process, does not make sense. Kicking (recent work has shown sauropods had vicious kicks) or tail swipes are far more reasonable for the big plant-eaters. This bothered me as far back as the Disney dinosaurs in Fantasia, when the stegosaurus turns to try to threaten T. Rex with its tiny mouth, instead of lashing out with its spiked tail. Now Disney may be forgiven – after all, Fantasia came out in 1940. Between making his dinosaurs animatable by artists drawing each cel by hand and the paleontological knowledge of the day, he did a respectable job even if his sauropods did have necks like snakes and his characters never actually lived at the same time. But that stegosaurus is pure theater, and Discovery Channel should have known better.

The third is grass. There is now some controversy over whether dinosaurs and grass coexisted, but the amount of grass shown is almost certainly incorrect.

Overall evaluation? Watch, but don’t believe everything you see. This DVD has a lot of creative interpretation, some of it almost certainly wrong.

DVD CoverThis set of two DVDs, although the cover has a date of 2008, in fact combines episodes originally aired on the Discovery Channel from 2001 to 2008. The first disc contains four episodes:  Valley of the T. Rex (2001), T-Rex: New Science, New Beast (2006), When Dinosaurs Roamed America (2001) and Utah’s Dino Graveyard (2005). Keep the true dates straight, because our interpretation of dinosaurs is changing rapidly, and the episodes at times seem to contradict each other. None of the interpretations are truly currant, or represent today’s ongoing controversies.

This DVD focuses on the processes of finding, unearthing and interpreting fossils, with only minor clips of computer generation of the living animals. It will be of more interest to budding paleontologists than to those looking for entertainment.

Valley of the T-Rex looks at the idea put forward by Jack Horner that T-Rex was primarily a scavenger, not a predator. The idea is hardly new, and is far earlier than the discovery of T-Rex’s tiny arms – Wiley Ley proposed it as a science article in the April 1943 issue of Astounding Science Fiction. I really doubt that there is any such thing as a pure predator or a pure scavenger. Any predator will scavenge a fresh kill, and any scavenger will kill an animal down and helpless, if only by eating it. Like the short-faced bear, T-Rex may have used its impressive size to intimidate other predators off their kills, but that doesn’t mean it never killed.

T-Rex: New Science, New Beast is more balanced, mentioning that how T-Rex fed is controversial but not getting into the controversy. Rather, it summarized new (as of 2006) methods of investigating dinosaur fossils. This included learning how to tell how old fossil dinosaurs were at death (which led to the discovery of the fantastic teenaged growth spurt of T-Rex and the relatively young age (29) of Sue, the largest T-Rex found.) At least one dinosaur was sexed, though the technique only works with pregnant (with eggs) females. Study of locomotion in modern animals has been applied to dinosaur skeletons, suggesting a lower top speed for full-grown T-Rex than was previously estimated. The episode also mentioned the discovery that some fossil bone had collagen, study of T-Rex bite strength, and the discovery of feathered theropods, leading to the possibility that T-Rex juveniles, at least, had downy feathers.

When Dinosaurs Roamed America goes through the history of dinosaurs, using an American location to spotlight each time period. Remember this segment, and the computer animated clips included, is eleven years old in 2012.

The video starts with New York (Permian-Jurassic, first dinosaurs, early opening of the Atlantic.) It then moves on to Exeter Township, PA (Triassic-Jurassic boundary, theropod-sauropod split.) Utah was a savannah 150 million years ago, wandered over by giant sauropods, their predators, and the smaller herbivorous dinosaurs that survived at their side. New Mexico 90 million years ago was a tropical swamp, with an explosion of flowering plants and broadleafed trees. The notorious K-T (Cretaceous-Triassic) boundary and the final extinction of the dinosaurs is investigated in South Dakota. The video is not bad, but dated.

The final program, Utah’s Dino Graveyard, covers a single location with a huge number of dinosaur fossils of a single species. Falcarius Utahensis was a strange beast even by dinosaur standards, as are most of its Therizinosaurian relatives. It is one of the earliest of a group that evolved from raptor-like carnivores to big-bellied but still relatively upright herbivores. This does happen – all dinosaurs, even the huge sauropods such as Apatosaurus evolved from early ancestors that ran on two legs and preyed on insects. More recently, the giant panda seems to be a bear that has embraced a diet of bamboo.

The real question is, what killed large numbers of the same species? Their preservation seems to be due to the fact that they all died near ancient springs, with rock from the spring deposits forming a cap that preserved their bones, but could the spring also have played a role in their deaths?

In general the computer graphics are adequate but not inspired, and at times show behavior I have doubts about — but I’ll save that critique for the second disc.

Back when IMAX theaters were rare and found mostly in museums I went to a 3-D IMAX show – T-Rex – at the Smithsonian Natural History Museum. Even then I found it a peculiar amalgam of three-dimensional animation, paleontology, and not-very-good science fiction. (OK, it’s pretending to be science fiction, but it’s closer to bad fantasy.)

I got the DVD a while back, when I was getting most of the dinosaur videos available.

It’s a 1998 movie, and of course a lot has been learned about T-Rex in the intervening 14 years. Not enough, however, to make me feel like trying to pet one, or think it was capable of gratitude to another species!

Both the animation and the sequences of paleontologists in the field are fascinating, and so is the information about museum displays and Charles Knight. If the producers had stuck to the informational part, and perhaps used the idea of T-Rex as a nurturing mother in a more reasonable way, this could have been an excellent film, though a short one (44 minutes.) However, they insisted on adding a plot which involved something that left the audience guessing whether dreams, hallucinations, or time travel was involved. The supposed resolution, with a paleontologist finding a 20th century watch, was totally ridiculous. Complex metal objects like watches simply do not fossilize.

Further, neither the big-screen of IMAX nor the 3-D were available in the DVD I have. This was a movie which depended on these effects.

Interestingly, there is considerable current research on the extent to which tyrannosaurs might have lived and hunted in family groups, and it is generally recognized today that birds are fundamentally modern dinosaurs, descended from the same bipedal group to which T-Rex belonged. The DVD, watched with the production date in mind, does give some interesting information on the history of how we think about dinosaurs. Just forget the plot!

p.s: As an update on last week’s post about ice jam floods, there is still a flood warning out for the Salcha River area, and the ice went out at Nenana at 7:39 yesterday evening. This can happen from April 20 to May 20, so breakup this year was early.

The usual four seasons, especially as defined by the equinoxes and solstices, don’t work very well for interior Alaska. Show cover is generally established by a month after the autumnal equinox, and stays on the ground until well after the vernal equinox. Rivers freeze a little later and remain frozen longer in the spring, and the only running water for six months of the year is in hot springs and indoors. But there is one season that everyone both longs for and dreads: Breakup.

Breakup is the time of year when snow melts and rivers thaw. The two are connected by more than sunshine and warmer weather. Melting snow makes mud (one of the reasons breakup is a time of some dread) but it also runs into rivers. If the water rises in the upper stretches of a river before lower reaches are thawed, as often happens in Alaska, the result can be ice jams and resultant flooding. I’ll talk about that some other time, but right now I want to discuss the simple process of melting snow.

Clean snow reflects most of the solar energy that strikes it. Some of the sun’s rays are absorbed within the snow pack, and cause internal melting and settling — but this is a slow process. Even clean snow, however, is a very good absorber in thermal infrared wavelengths. The sun doesn’t put out much energy in these wavelengths, but buildings, trees, and just about everything else except polished metal does. As a result, snow near the south side of a building melts much faster than snow out in the open. So does snow near tree trunks.

I see this every year. In addition to the photo of my road, which is rapidly turning into mud, I took two of the north and south yards of my house, minutes apart. Both areas got almost exactly the same amount of snow, and both have very similar exposure to sunlight. The snow stake still has a good 18” of snow. The ground around the birch is almost bare.

Why? Two reasons, actually, and the combination explains why open birch forest is usually the first natural area free of snow around here. First, birch trees hold their seeds through winter, and drop them shortly before breakup. As a result the seeds on the snow around the tree absorb the solar radiation and transfer that energy to the snow, speeding its melt. Natural selection? Quite possibly. It certainly seems likely that the enhanced snow melt, leading to earlier warming of the ground, would help the tree.

Second, the tree itself absorbs some solar energy, and then re-radiates it to the snow in the form of thermal infrared. Just about any object poking through the snow this time of year has a little depression around it. Spruce trees do an even better job of absorbing sunlight than do birches, but they also shade the ground and transfer much of the energy they absorb directly to the air. As a result spruce forest, while it probably does a better job of warming the air than birch forest, is among the last areas to have completely bare ground.

On a different note entirely, one of the fixtures of breakup in Fairbanks is the Beat Beethoven 5 km race, a fundraiser held today for and by the Fairbanks Symphony Orchestra. I won’t be running this year, though I did “run” with a cane once — and came in last. The idea is to cover the 5 km before the end of Beethoven’s 5th Symphony, about 30 minutes. I’m volunteering this year to park my car along the race route with the radio tuned to 91.5 (KSUA, the campus radio station) blaring out Beethoven’s 5th. I expect temperatures below 50°F and much of the course to be slippery or wet!

Added later (after the race.) This is definitely a family race. There were parents pushing their children in strollers, parents with children in backpacks or riding piggyback, dogs, and one contestant on crutches. (And she wasn’t at the end, either.) I did have a bit of a problem in that instruction to volunteers said if possible, not to have your car idling as the runner went by. I did. And needed a jump to start the car after the battery totally discharged itself.

All dinosaurs are bizarre, by mammalian standards. Some, however, are bizarre even to paleontologists, and the title program of this DVD is devoted to them. There is, however, a secondary program, not even mentioned on the cover, which to me was of considerably more interest.

Most of these animals are considered bizarre because they have appendages, preserved in the fossil record, that leave paleontologists wondering just why these animals have that appendage. Take the 33 foot-long Anargasaurus, for instance. Why on earth did this plant-eater have a double row of bony spines down its back? Reconstructions tend to show it with skin forming a double crest supported by those spines, but why? The only answer anyone had come up with is some kind of display crest, like the peacock’s tail.

Display organs are common, especially in today’s birds (which after all are modern dinosaurs) so I suppose it’s as good an explanation as any for such things as the plates of a Stegosaurus (which would have been potato chips to a large carnivore) or for the fanciful neck frills, often richly supplied with blood, of the Ceratopsids. Were horns used to fend off predators, of for fighting off rivals within the species? Or just for display?

In some cases the peculiarities might be associated with feeding. Take the Epidendrosaurus, for instance, a sparrow-sized dinosaur with an incredibly long third finger. Did it use its long finger as the aye-aye in Madagascar today does, to find insects in the bark of trees? Then there’s Nigersaurus, with a broad, flat head with a very wide muzzle resembling a vacuum-cleaner nozzle. Did it stand in one place and hoover up the vegetation?

This DVD is less interesting than most of the National Geographic programs scientifically, but it does show some interesting dinosaurs. If you want information on some of the animals shown, National Geographic has both an interactive site and a magazine article by John Updike.

The secondary program, which was a total surprise, should have been part of the Prehistoric Predators DVD I reviewed earlier. It was concerned with a much more recent animal, one I’d met before in Prehistoric Park—a predatory, flightless bird that could almost hold its own with sabertoothed cats and dire wolves. Certainly it seems to have taken down the same kind of prey.

These terror birds were not what you want to attract to your backyard bird feeder! Imagine an oversized ostrich with the hooked beak of a raptor, that beak (and head) enlarged to the size of a rather large war axe. With ostrich speed and taller than a man, they evolved to be the top predators on the South American continent, for many millions of years an island continent. Then a few million years ago, the isthmus of Panama joined it to North America, ending the isolation in which the terror birds had evolved. Animals crossed the new isthmus both ways. Opossums, armadillos, and porcupines moved north, but a far greater number of placental mammals moved south.

Surprisingly, a few terror birds did move north, as their fossils have been found in Florida. Did they meet with the earliest humans to colonize North America? Or were they simply unable to compete with the mega-predators already here? They did seem to survive for a long time in North America, but the jury is still out on just how long they lasted.

Tomorrow’s the day to look at quotes from Lewis Carroll, but I’ll also have a guest appearance on another blog, Christine’s Words. Stop by!

This is the first of a number of reviews of National Geographic’s DVDs on prehistoric animals, so I will start out by saying something that applies to all. They are very good in interviews with actual paleontologists. The computer graphics of the extinct animals are of moderate quality, and there are only a few clips repeated over and over again. These videos are excellent for budding paleontologists or those actually interested in the science of how we know about extinct animals, and are better than series like “Walking With Dinosaurs” in that they allow scientific arguments to be heard. They are not in the same league when it comes to the re-creation of the extinct animals.

This DVD contains two programs originally shown on the National Geographic channel: Dino Autopsy and Dino Death Trap. The first is about a rare fossilized mummy of a hadrosaur, nicknamed “Dakota,” found in the badlands of North Dakota. The fossil was found in 1999 by a teenaged paleontologist, and has supplied information on skin texture and musculature of hadrosaurs. The science is fascinating. The quality of the animation is somewhat less so.

The second program involves the excavation of a site in China. This site produced a number of near-complete skeletons from a period, the Late Jurassic, very poorly represented until now. Most of the attention is given to Guanlong, a very early form of tyrannosaurid. The skeletons are in three dimensions rather than flattened, which has been interpreted as evidence that they were trapped in soft sediments, and lie above each other in a vertical column.

There is speculation about how they died included in the video. Was a volcanic eruption to blame? Was the mud in which they were trapped due to volcanic ash falling into a marsh? Also, while these animals are the early forms of species known from the Cretaceous, the Cretaceous forms were giants, and these animals are relatively small. Guanlong’s back would about reach the waist on a standing human, yet it is an early relative of Tyrannosaurus Rex. What caused the increase in size? Did guanlong really have feathers as part of its crest? They are in the computer animation, and a relative, Dilong, is known to have had primitive feathers. The crest does appear to be a display organ (relatively thin and brittle) and feathers would have made it more conspicuous.

Overall the DVD is worth watching if you are really interested in dinosaurs. If you are looking primarily for entertainment, others are better.

Here are links to all of the posts I would count as science, including those that explain how I use science in my science fiction. This list will be updated as new science posts are added. (Note that some posts listed under “Health” or “Technology” may also be of interest.)

The Science Behind Homecoming 4/2/10
Why do we have Weather? 4/24/10
Precession – Astronomy and Milankovitch 5/6/15
The Four Horsemen of the Apocalypse 6/12/10
Why Planets Have Seasons 6/24/10
Full of Sound and Fury (Fireworks) 7/3/10
Tricycles are not Bicycles 8/8/10
Planet Building 8/15/10 – 10/24/10
Racemization 9/2/10
Equinoxes and Daylight Savings 9/23/10
Horse Color Genetics 10/31/10 – 5/8/11
R’il’nai, Humans and Crossbreds: Life Span 12/11/10
Conservation Laws of Energy and Teleportation 12/20/10
Winter Solstice 12/22/10
Mass into Energy 12/24/11
Momentum and Teleportation 1/1/11
Snowflakes 1/7/11
Ice Fog: Ground Level Contrails 1/25/11
The Planets of Tourist Trap: Eversummer 3/6/11
Earthquakes, Tsunamis and Volcanoes 3/13/11
Why 12-Hour Days Already? 3/19/11
Ice Sculpture: Ice and Sun 3/26/11
More on Ice Melting 3/27/11
Why Temperatures Remembered Don’t Match the Record 4/5/11
When It’s Springtime in Alaska 4/8/11
Twilight 4/12/11
How High the Moon? 4/15/11
Breakup 4/16/11
The Cambrian Explosion 4/22/11
How Did We Learn to Walk? 4/29/11
Back to the Water 5/6/11
Where did the First Plants Come from? 5/13/11
The Geophysical Institute 5/15/11
Alaskan Mosquitoes 5/19/11
Colored-Leaf Geraniums 5/20/11
Early History of the Geophysical Institute 5/22/11
The Fairbanks Flood of 1967 5/29/11
Before Computers 6/5/11
Ice Ages and Alaska 6/17/11
Cumulus Clouds and Cloud Streets 6/24/11
Plate Tectonics Part I 7/1/11
Plate Tectonics Part II 7/8/11
Plate Tectonics Part III 8/5/11
Frost Hollows 8/19/11
Be Careful What You Ask For 8/27/11
Autumn Colors 9/10/11
Thermometers in Fairbanks 9/17/11
Junk Mail and Plants 9/20/11
The Chimney Sweep 9/22/11
Lights, Batteries, Temperatures? 9/24/11
How Dry I Am 10/15/11
Keeping Windows Dry 10/22/11
Snowflakes 10/29/11
The Alaskan Mesozoic 11/1/11
Mesozoic Alaska Part 2 8/11/11
Alaskan Mesozoic 3 11/15/11
Death of Blue Babe 11/17/11
Nightlength Sensitivity in Houseplants 12/10/11
Our Sense of Smell 12/17/11
What Time of Day is Warmest? 12/31/11
Alaska Winter Weather: Cordova and Nome 1/14/12
Inversions and Smokestacks 1/28/12
January Wasn’t Warm in Alaska 2/4/12
Fog, Fog, Fog 2/11/12
Oceanography DVD Review 2/14/12
Snow Festoons 2/18/12
Disturbance Hardening of Snow 3/24/12
Cold-Packed Snow and White Ice 3/31/12
Tornadoes and Climate Change 4/7/12
Breakup Season 4/14/12
Ice Jam Floods 4/21/12
Calories and Weight 5/5/12
Battery Woes 5/12/12
IRT Plastic: Using the Sun 6/2/12
A Love Affair with Begonias 6/7/12
The Transit of Venus 6/9/12
How does Rain Form? 6/16/12
If Earth were on its Side 6/22/12
Day and Year Lengths of the Planets 6/23/12
Chickweed and Mosquitoes 6/28/12
Flowers and Sex 6/30/12
Salpiglossis (Painted Tongue) 7/5/12
How Long is your Night? 7/7/12
Colorado Storm 8/2/12
Could Jarn have Made Glass? 8/11/12
Seeing the Jet Stream 8/18/12
A Bird in the Hand 8/23/12
Radiation Frosts 9/1/12
Alaska Sky 9/25/12
Sky Photo 9/27/12
Flower Photos 10/9/12
Start of the Seasonal Snowpack 10/18/12
Sunrise and Sunset in Fairbanks (video) 12/27/12
Video from Barrow, Alaska the first day of Sunrise 1/24/13
We Have Puddles! 4/20/13
DNA: We All Have it 6/1/13
My Maternal DNA 6/8/13
Winter Solstice in Fairbanks 12/21/13
Glaciation 4/8/14
Mints, Part 1 6/2/14
Mints, Part 2 6/5/14
Rosemarys 6/12/14
Thymes 6/17/14
Basils 6/19/14
The Summer Solstice 6/21/14
Other Culinary Herbs 6/24/14
Lavenders 6/26/14
Annual flowers in Alaska 6/28/14
First Daylily of 2014 7/1/14

With 550 posts as of today, I’ve started to have problems remembering what I’ve already put on here. This is particularly a problem with posting existing content such as poems, short pieces from the Summer Arts Festival, or science explanations originally written for the Alaska Science Forum. I can’t remember which books or DVDs I’ve posted reviews on. It also is starting to be a problem when I want to link to a previous post and can’t remember when it was put up or what the title was. And there are posts on this blog that have permanent information, like the series on planet building and the one on horse color genetics, or the book and DVD reviews. I want to make it easier for my readers as well as myself to find things.

I made a start some time ago by adding an index page, which can be accessed from the menu at the top of any page. Right now, the only links are to index pages on my author site. This takes you out of the site and sometimes back in, which is rather clumsy. The index list is also incomplete.

I’m going to start posting an occasional entry which is strictly an index of past posts on a particular topic. These posts will be linked from the index page, and will link forward to the individual blog posts. As it takes a while to find all the posts that belong together, this will be a slow process—probably extending over the next few months. The first in this series, on DVD reviews, is already queued for January 3. Others will follow, most on Thursdays.

I probably won’t be indexing every post. Some, like those early posts which were simply glossary entries for my books, are on the author site and really belong there. Others, like the regular Monday updates on North Pole weather starting in November 2010, can be found easily enough just by using the calendar on the site. But I hope that by the time I have finished this, older posts of interest will be easier to find.

I ran across an article recently claiming that modern humans have a better sense of smell than Neanderthals.

Well, some modern humans.

I happen to be practically devoid of a sense of smell. Maybe it’s years of allergies. Maybe it’s diabetic neuropathy. Maybe it’s living in a cold, dry climate. Neanderthals do appear to have been better cold-adapted than modern humans who, after all, evolved in Africa. But the fact remains that my eyes start burning from charring food on the stove before I smell it. And I can’t even smell the odors from some of my plants, including mint, unless I rub or crush the leaves. I have to put my nose right into fragrant roses, jasmine or citrus blossoms before I smell them.

It hasn’t always been that way. I can remember smelling the differences between herb plants at a nursery, for instance, and sniffing appreciatively at pineapple sage and lemon verbena. I’m sure lilacs once spread their scent, while I now have to bury my nose in a panicle to get anything.

It’s not all a loss, of course. I remember also the stench of my grandparents’ outhouse, especially in summer, and deep-cleaning a dirt-floored stall in spring. Considering what sanitation was like a couple of centuries ago, I suspect that modern humans must have learned to turn off or ignore their sense of smell pretty often, just as a matter of survival.

Strangely I am still sensitive to some odors, especially cigarette smoke and some artificial perfumes. But they make my eyes water as well as being distinctly unpleasant odors, and I suspect my reaction may be linked to the fact that “perfumed” detergents make my skin itch.

But now and then I notice a pleasant odor. Right now, it is narcissus.

They started blooming this week, next to the kitchen table. I saw them first, but the last couple of days my meals have had a distinct, intensely floral narcissus flavor. I remember how my mother used to force narcissus bulbs. I am still sensitive to the link between odor and memory, it seems.

In fact, writing about odors often brings things to mind I have almost forgotten. The smell of cut green grass, for instance, brings back the years one of my chores was cutting the Bermuda grass with our old push mower. Not too surprising in terms of brain wiring – the sense of smell is the only one that goes straight from the environment into the brain, but it’s interesting that simply remembering a smell from when I could detect it has the same effect.

I can’t help but wonder how much variability there might be, both in modern humans and in Neanderthals, in the capacity to detect and distinguish odors.