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Tag Archives: fossil

Evidence of Man for Eons to Come

I don’t mean to exclude women at all, in fact, I really mean that evidence of humans show signs of lasting for eons to come, but it just didn’t sound like a title to me.

ImageAnyway, what do I mean?

Enter Plastiglomerate rock.

Science magazine explains, ” When the plastic melts, it cements rock fragments, sand, and shell debris together, or the plastic can flow into larger rocks and fill in cracks and bubbles to form a kind of junkyard Frankenstein.” Hawaii appears to have just that perfect mix of steady volcanic activity and trash-generating humans to spawn these new rocks.

ImagePatricia Corcoran, of the University of Western Ontario in London, Canada, describes how the accumulation of plastic waste material since the 1950s has resulted in this phenomenon of plastic entering into the fossil / geologic record. The unique characteristics of Pacific Ocean create what is known as the North Pacific Gyre, that collects and concentrates waste of all kinds into an area known as the Eastern Garbage Patch. Kamilo beach, located on the southern tip of the big island, provides an excellent place for this vast amount of marine – and now human- debris to accumulate. Once this trash – including a significant amount  of long-lived plastic- comes into contact with the volcanic islands of the Pacific, it has the opportunity to become Imagefused, via the heat of the lava, with this igneous rock and sand resulting in the newly minted plastiglomerate rock which can now settle onto the sea floor and become a ‘permanent’ part of the fossil record. Perhaps these rocks will become the coprolites of our age, abundant records of our waste, for future generations to find.

 
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Posted by on June 6, 2014 in Uncategorized

 

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Your Inner Fish on PBS

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Tiktaalik

The HHMI’s Tangled Bank Studios will be airing a three part PBS documentary based on Your Inner Fish by Neil Shubin. The documentary, like the book of the same name, asserts that, “It took more than 350 million years for the human body to take shape.” And asks, “How did it become the complicated, quirky, and amazing machine it is today?” Broadcast is scheduled for Spring of 2014.

Perhaps this will be the last semester that we read the book in my General Biology class in favor of watching the film version and adding a new read to accompany the class. There are a lot of books I would like to go with, but here’s the opportunity for you to send your suggestions.

paleomaps

The Earth during the Devonian

While you’re at it, I am also starting to teach an Ecology / Genetics class next semester (offered for the first time at our campus) and would be interested to have your suggestions for a book to read with that class as well. So, please send your ideas for a fun reads (I would love to read The Selfish Gene, but have nixed it for failing in the ‘fun’ department) that you think students of General Biology and Ecology / Genetics should read.

 
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Posted by on September 2, 2013 in Uncategorized

 

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Link

We will be discussing Radionuclide dating this week in class. This is how we can know how old certain types of fossils, bones, rocks, etc are –  especially when they are so old that no one was around to see them and write down the date. In fact, this type of dating can even help us determine how old some things are from a time before there was any humans around at all. This video, from scientific american, does an excellent job at introducing the concept using carbon dating as an example.

http://link.brightcove.com/services/player/bcpid1202686955001?bckey=AQ~~,AAAAAFNl7zk~,OmXvgxJOvrEZGUO9zkRu0HqtcBY54xr3&bctid=2000896327001

The general idea is that there are two common types of Carbon, Carbon-12 is the non-radioactive form and Carbon-14 is a radioactive form of the same element. The only difference between the two is that C-14 breaks down by radioactive decay at a certain rate. Once it decays, C-14 will be transformed into Nitrogen.

There is a steady ratio of C-12 / C-14 in the atmosphere that gets incorporated into plants during photosynthesis, and eventually makes its way into all organisms through the food chain. Therefore, this ratio of Carbon will also exist in all living beings and will remain at this steady state until the last time this organism ingests a Carbon food source (just before it dies). From that point on, the Radioactive Carbon will decay, while C-12 remains steady.

The rate of radioactive decay is called the ‘half-life’, which is the time it takes for half the radioactive material to decay. This means we can watch the ratio of the two elements over time, and by determining how many halves have decayed, we know how long it has been since the organism died.

Below, I’ve made a graph similar to the one in the video to show how this looks (Click for Enlarged Image):

A Geiger Counter illustrates the reduction of radioactivity over several half-lives. A. Detail of the Geiger Counter. Higher counts (9 o'clock) indicate more radioactive material. B. Graph of radioactive material decaying vs non-decaying material.

A Geiger Counter illustrates the reduction of radioactivity over several half-lives. A. Detail of the Geiger Counter. Higher counts (9 o’clock) indicate more radioactive material. B. Graph of radioactive material decaying vs non-decaying material.

 
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Posted by on December 1, 2012 in Uncategorized

 

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