Why the Canadian Arctic?

Throughout this past month, we talked a great deal about Tiktaalik. I was immediately interested in this topic and eager to learn more about the creature that came from water onto land. We learned a lot about this creature, however, I still wondered about how the scientists discovered this creature. I wanted to know how the scientists were able to specifically identify the area they did to look for him. Based on an interview with Neil Shubin, I found that he discovered the location in a textbook for undergraduate geology. The three locations where rock that was 380 to 360 million years old were Eastern North America, Greenland, and the Canadian Arctic. The scientists chose this location to look for the fossil because no one had previously looked in the area. It has been extremely challenging to get to the location because of various permits and money that was needed for the many expeditions (Shubin, 2006). It seems that the researchers were very resourceful and put in a lot of effort for their expedition.

In class, we had already learned that the Canadian Arctic, about 1500 km long, was a perfect location to search for fossils because there is virtually no vegetation. As we saw in the video, the land was barren, which really allowed the scientists to be able to search for fossils. I wonder if they would have discovered Tiktaalik if there were trees, plants, dirt, ect. on the land? It would have definitely make the process go much longer.

I also learned how hard it is actually locate fossils.  Neil Shubin said that they had to go up to the location four different times over a course of six years. Each time they went up to the site, they discovered more and more. First nothing, then some bits of pieces, then larger pieces of fish fossils, and then in July of 2004 they discovered the whole skeleton to what they named Tiktaalik (Shubin, 2006). I am still in awe that they were able to find Tiktaalik mostly whole, after being in the rock for so long.

One last thing that I learned that was extremely interesting was why they named the vertebrae Tiktaalik. The Nunavut territory in Canada contained a group of elders who came up with the name. In their language, the Inuktitut language, it means a “large, freshwater fish” (Shubin, 2006). It is very fitting!

In terms of learning anything additional, I would like to know if any other fossils have been found that are descendants of Tiktaalik. It would be interesting to know if any full fossils of vertebrates have been found in the same area, as it is easier to identify with the barren land.  I hope that the researchers return to that area because of the success they eventually achieved there in 2004.

Shubin, N. (n.d.). Tiktaalik roseae: Home. Retrieved October 29, 2014.

Coevolution: Native and Invasive Plants

Reported in June 2012, the University of Georgia conducted a study in which it found that invasive species (kudzu, privet, and garlic mustard) and native plants (Clearwater plant) are currently undergoing co-evolution. Prior to this research, scientists believed that the native plants were unable to combat the invasive plants, which were introduced from Europe during the mid-1800’s. Yet, the study gave the first evidence to show that the native plants possibly evolved resistance to the garlic mustard plants. Yet, this is a prime example of co-evolution because the invasive plants are fighting back.

            When the invasive plants were introduced in the 1800’s, they quickly spread from New York, Virginia, and Chicago to the Northeast, Southeast, and the Midwest. They are able to survive by fighting with a compound called Sinigrin. This compound kills the fungi that helps native plants get nutrients from the soil. It is so effective because Sinigrin is new to North America. It is able to kill the native plants because these plants did not have a resistance to the compound. In addition, the invasive plants are able to survive because even after they are removed, they grow back after a year as forest undergrowth.

            Richard Lankau, who works at the university, has found evidence that the native plants have evolved because of the invader plants. He took a native Clearwater plant called Pilea pumila and found that it has higher resistance to Sinigrin. This shows that since this plant is in the same habitat as the garlic mustard, co-evolution has occurred. To explain further, he was able to get to this information because he found that the garlic mustard (the invasive plant investigated in his experiment) produced more Sinigrin in areas with more native plants.

            Lankau also found that the native plants were more successful at surviving when the garlic mustard was present. To figure this out, he took the native plants back to their origin location that did not have garlic mustard. The native plants that had already created a resistance did not survive as long without the garlic mustard present as the native plants that were not resistant when exposed with the garlic mustard. "It's not all good for those populations that are evolving tolerance because they are less successful in the absence of garlic mustard, their resistance to the invasive species comes at a cost” (Lankau 1).

            To conclude, the native and invasive plants are currently undergoing co-evolution and it is believed that at one point in time in the far future they may be able to coexist with each other.

Garlic Mustard

Pilea pumila

Fahmy, Sam (2012, June). Study Provides First Evidence of Coevolution between Invasive, Native Species. Retrieved October 19, 2014 from UGA Today.