His website has some useful resources including details on making leaf skeleton, and his blog has fascinating articles about leaves from the cost of producing veins and their function to colour change to how plants survive with only the occasional flash of sunlight through the dense canopy above.
Showing posts with label fossil. Show all posts
Showing posts with label fossil. Show all posts
Friday, 12 August 2011
12th August 2011 - 1 Can Leaf Veins Be Used To Predict Climate?
Benjamin Blonder, an ecology graduate student, working with his advisor Brian Enquist at the University of Arizona in Tucson is examining the connection between the veins in leaves and climate. Preliminary results from his models predict temperature and precipitation. I'll be very interested to see if these preliminary results hold up when tested more widely and whether they can be extrapolated to accurately determine climate from fossil records, as he suggests.
His website has some useful resources including details on making leaf skeleton, and his blog has fascinating articles about leaves from the cost of producing veins and their function to colour change to how plants survive with only the occasional flash of sunlight through the dense canopy above.
His website has some useful resources including details on making leaf skeleton, and his blog has fascinating articles about leaves from the cost of producing veins and their function to colour change to how plants survive with only the occasional flash of sunlight through the dense canopy above.
Thursday, 26 May 2011
26th May 2011 Coral and Day Length
Coral lays down a layer of calcium carbonate every day. These layers can be counted, and so a thicker layer of 365 of them represent a year. Without knowing the length of a year, could we tell it's 365 days? Yes. The thickness of the layers varies with the seasonal variation in day length so there is a cyclic pattern to the layers. [2]
What about coral fossils? What do they tell us? Looking at fossils from 400 million years ago, there are about 410 layers per year. [1] What does this mean? Since the time it takes Earth to orbit the Sun is constant, it means that the length of a day was shorter, about 21 hours long [1,2]. Hence the earth is now spinning more slowly than it was 400 million years ago. Extrapolating back to 4.5 billion years ago, when a massive collision caused the formation of the moon [3], each day would only last about 6 hours.[1]
What about coral fossils? What do they tell us? Looking at fossils from 400 million years ago, there are about 410 layers per year. [1] What does this mean? Since the time it takes Earth to orbit the Sun is constant, it means that the length of a day was shorter, about 21 hours long [1,2]. Hence the earth is now spinning more slowly than it was 400 million years ago. Extrapolating back to 4.5 billion years ago, when a massive collision caused the formation of the moon [3], each day would only last about 6 hours.[1]
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