Air- and waterborne seeds became more common between the late Carboniferous—320 million years ago—and early Permian, which began about 300 million years ago. At the time, most plant life consisted of lycopods, ferns, horsetails, and seed ferns, with a few of the first cone-bearing trees, like conifers and cycads, appearing.
“There were very different plants around at the time,” Looy says. “Several of these groups produced seeds, but they lacked most of the tricks we see today to spread them.”
A single-winged seed falls until it starts to autorotate, which slows its descent.
Vertebrates, only a few of which were herbivores, were typically large and did not climb trees. The only flying animals were insects, and as far as we know they did not disperse seeds, Looy says.
“For a seed at that time, having wings was actually one of the few ways to spread widely,” she says.
When conifers took flight: a biomechanical evaluation of an imperfect evolutionary takeoff
Robert A. Stevensona1, Dennis Evangelistaa1p1 and Cindy V. Looya2
a1 Department of Integrative Biology, University of California, Berkeley, 3060 Valley Life Sciences Building #3140, Berkeley, California 94720, U.S.A
a2 Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, 3060 Valley Life Sciences Building #3140, Berkeley, California 94720, U.S.A.
Manifera talaris, a voltzian conifer from the late early to middle Permian (ca. 270 Ma) of Texas, is the earliest known conifer to produce winged seeds indicative of autorotating flight. In contrast to autorotating seeds and fruits of extant plants, the ones of M. talaris are exceptional in that they have variable morphology. They bore two wings that produced a range of wing configurations, from seeds with two equal-sized wings to single-winged specimens, via various stages of underdevelopment of one of the wings. To examine the effects of various seed morphologies on aerodynamics and dispersal potential, we studied the flight performance of paper models of three morphotypes: symmetric double-winged, asymmetric double-winged, and single-winged. Using a high-speed camera we identified the mode of descent (plummeting, gliding, autorotation) and quantified descent speed, autorotation frequency, and other flight characteristics. To validate such modeling as an inferential tool, we compared descent of extant analogues (kauri; Agathis australis) with descent of similarly constructed seed models. All three seed morphotypes exhibited autorotating flight behavior. However, double-winged seeds, especially symmetric ones, failed to initiate slow autorotative descent more frequently than single-winged seeds. Even when autorotating, symmetric double-winged seeds descend faster than asymmetric double-winged ones, and descent is roughly twice as fast compared to single-winged seeds. Moreover, the relative advantage that (effectively) single-winged seeds have in slowing descent during autorotation becomes larger as seed weight increases. Hence, the range in seed wing configurations in M. talaris produced a wide variation in potential dispersal capacity. Overall, our results indicate that the evolutionarily novel autorotating winged seeds must have improved conifer seed dispersal, in a time when animal vectors for dispersion were virtually absent. Because of the range in wing configuration, the early evolution of autorotative flight in conifers was a functionally imperfect one, which provides us insight into the evolutionary developmental biology of autorotative seeds in conifers.
The plane then took a nosedive for 27 seconds, losing 4,400 feet during that span and causing injuries to 33 of the passengers and crew. The report concludes that the case was a “near-miss” that had “realistic potential for the loss of the aircraft and 198 of our people.”
Although the military pilot was not prohibited from using his camera during the flight — and in fact the photography may have helped him be alert during times of boredom — this incident will soon lead to new rules that prohibit things from being placed between the armrest and joystick.
In 1995 a symposium celebrating the 50th anniversary of Vannevar Bush's As We May Think article was held at Brown. I've seen many of the videos, but stumbled into a complete collection on the Doug Engelbart Institute's site. Fascinating viewing for those with an interest in the history of technology.
Long before Stanford University was considered a technology powerhouse, its most lucrative patent came from an under-spoken composer in its music department. Over the course of two decades, his discovery, "frequency modulation synthesis," made the school more than $25 million in licensing fees.
But more importantly, FM synthesis revolutionized the music industry, and opened up a world of digital sound possibilities. Yamaha used it to build the world’s first mass-marketed digital synthesizer — a device that defined the sound of 80s music. In later years, the technology found its way into the sound cards of nearly every video game console, cell phone, and personal computer.
Despite the patent’s immense success, its discoverer, Dr. John Chowning, a brilliant composer in his own right, was passed over for tenure by Stanford for being “too out there.” In Stanford’s then-traditional music program, his dabblings in computer music were not seen as a worthy use of time, and he was largely marginalized. Yet by following his desire to explore new frontiers of audio, Chowning eventually recontextualized the roles of music and sound, found his way back into the program, and became the department chair of his own internationally-renowned program.
This is the story of an auditory pioneer who was unwilling to compromise his curiosity — and who, with a small group of gifted colleagues, convinced the world that computers could play an important role in the creation of music.