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Calcium and Vitamin D Supplements Still Don't Work, New Study Says1 month ago in Genomics, Medicine, and Pseudoscience
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The Site is Dead, Long Live the Site1 year ago in Catalogue of Organisms
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The Site is Dead, Long Live the Site1 year ago in Variety of Life
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Does mathematics carry human biases?3 years ago in PLEKTIX
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A New Placodont from the Late Triassic of China5 years ago in Chinleana
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Posted: July 22, 2018 at 03:03PM5 years ago in Field Notes
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Bryophyte Herbarium Survey6 years ago in Moss Plants and More
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Harnessing innate immunity to cure HIV7 years ago in Rule of 6ix
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WE MOVED!7 years ago in Games with Words
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post doc job opportunity on ribosome biochemistry!9 years ago in Protein Evolution and Other Musings
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Growing the kidney: re-blogged from Science Bitez9 years ago in The View from a Microbiologist
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Blogging Microbes- Communicating Microbiology to Netizens9 years ago in Memoirs of a Defective Brain
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The Lure of the Obscure? Guest Post by Frank Stahl11 years ago in Sex, Genes & Evolution
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Lab Rat Moving House12 years ago in Life of a Lab Rat
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Slideshow of NASA's Stardust-NExT Mission Comet Tempel 1 Flyby13 years ago in The Large Picture Blog
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in The Biology Files
A plant pundit comments on plants, the foibles and fun of academic life, and other things of interest.
Tropical leaf drip tips - yam
A student asked a good question the other day after telling them about past climatic differences. How do we know what the climate was like millions of years ago? One answer too frequently heard is that we can't know because no one was there to observe the climate. In the real world observations can still be made about the past. For example, leaves display different forms as adaptations to different climates. Here's a leaf from a yam (Dioscorea), which is not a sweet potato. The leaf shows a couple of adaptations for a wetter environment. First it's a fairly large leaf, and leaf size is very generally correlated positively with warmer wetter climates. Note the attenuated apical tip, a drip tip, with a drip on the tip, and like the pouring lip of a beaker or pitcher, that tip helps water drip and pour off the leaf more efficiently. The major veins that generally follow the out line of the leaf margin from base to tip form valleys, gutters, again to help water pour off the leaf. So when you find fossils with such features, or with features associated with very seasonal climates, or very dry climates, paleobotanists, infer that they were adapted to a particular climate suited to that leaf type. And if that's not so, then maybe those leaves weren't well designed after all.
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