Galapagos Daily: Measuring evolution

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The rocky islet of Daphne Major viewed from North Seymour Island. In 1973, Peter and Rosemary Grant of Princeton University began a decades-long study of the finches living on Daphne Major. They banded and measured every finch on this island laboratory, measuring heritable traits such as beak size, and documenting how seasonal variation rolled the dice in a game of life or death for its feathered inhabitants. Drought years caused a shift in beak sizes among finches as the larger beaks were better adapted to open the harder, armed seeds that were the only food left. Birds with larger beaks survived and reproduced, the next generation had larger average beaks. Evidence of natural selection and evolution, measured over decades one beak at a time.

The rocky islet of Daphne Major juts above the Pacific as seen from North Seymour Island. In 1973, Peter and Rosemary Grant of Princeton University began a decades-long study of the finches living on Daphne Major. They banded and measured every finch on this island laboratory every year, measuring traits that can be passed down, such as beak size. Through time and generations of finches, they documented how seasonal variation rolled the dice in a game of life or death for its feathered inhabitants. Drought years caused a shift in beak sizes among finches as the larger beaks were better adapted to open the harder, armed seeds that were the only food left on this desert island. Surviving birds had larger beaks, they reproduced, and the next generation had larger beaks. Evidence of evolution by natural selection, measured over decades one beak at a time.

 

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Galapagos Day 5: Galapagos penguins!

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The only penguins found in the northern hemisphere are endemic Galapagos penguins (Spheniscus mendiculus). Unlike their arctic brethren, Galapagos penguins must adapt to heat since their population straddles the equator. Besides cooling themselves in the water, they hunch over to shade their feet and pant like dogs to cool their throats and nasal passages.
Galapagos penguin populations decline in El Nino years, when sea temperatures remain warm and food (small fish like sardines) becomes scarce. The penguins’ breeding cycle is driven by sea surface temperatures, and they often do not breed at all in El Nino years. In addition, invasive dogs, rats and cats eat the eggs and destroy their nests. Our guide told us that scientists worry that the current population could not survive another El Nino. With fewer than 1000 breeding pairs, the Galapagos penguin is the rarest penguin in the world.

Galapagos Day 4+: Land iguana

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Galapagos Day 4+: Land iguana

On our hike to Volcan Chico on Isabela yesterday, we saw our first land iguana, Conolophus subcristatus, in a dry habitat beneath scrubby shrubs. Another species found only on the Galapagos Islands, these iguanas can interbreed with the marine species (surprising since they are a different genus) but the hybrid offspring are sterile. This suggests that the land and marine iguanas shared a common ancestor, a question that could be answered by DNA testing.

Galapagos Day 3: Giant tortoises

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Galapagos Day 3: Giant tortoises

There are 11 varieties of the Galapagos giant tortoise (Geochelone elephantopus) remaining of the 15 found during Darwin’s time; they are endemic, found nowhere else on Earth. Their numbers were greatly impacted in two ways 1) Hunting; tortoises were taken by the hundreds aboard ships. They were an excellent food source, because they could live in the ship’s holds for up to a year without food or water. 2) Introduced species; ship rats devoured the young turtles and goats decimated the native vegetation. The Charles Darwin Research Station now conducts a successful captive breeding program and turtles are protected throughout the islands. DNA research will also lead to a better understanding of how these varieties evolved from a single ancestral species.

 

Galapagos Day 1: Sea lions!

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We got nose-to-nose with this curious baby sea lion (Zalophus califorinianus wollebacki) at a beach on San Cristobal, and saw adults swimming far off the coast. Their favorite food is sardines, so El Nino events, which bring warmer waters and a decline in marine life to the Galapagos, decrease their populations. The Galapagos sea lion population numbers 50,000 animals, and the only other place they are found in the world is Isla Gorgana, off the Ecuadoran coast. Nearby we saw a few adult females, including a mother nursing her pup.

An ecologist goes home: Galapagos Preview

“The ideal scientist thinks like a poet and works like a bookkeeper, and I suppose that if gifted with a full quiver, (s)he also writes like a journalist.” E.O. Wilson

One of the hats I wear is that of a teaching assistant professor in the Department of Forestry and Environmental Resources at NC State. I earned my Ph.D. in forestry from State and love teaching there. Although I’m trained as a forest ecologist, most of my teaching is in professional development. My career has taken many twists and turns and I have lots to say about it, some of which helps students. It’s rewarding and fun.

But I miss ecology and teaching science, which is why I continue to teach field classes at the NC Botanical Garden and elsewhere. When a long-time professor retired and his study abroad class to the Galapagos was left open, I immediately emailed my department head to tell him that he needed a co-instructor and that I would be great for the job. Sometimes you have to be direct. So I was.

I subscribed to World before polar bears were listed as threatened.

I’ve wanted to go to the Galapagos Islands for a very long time. When I was a kid, I eagerly awaited my monthly National Geographic World magazine. My dream was to travel the world and write for National Geographic. I was 12 or 13 when I entered an essay contest sponsored by World. I’m a little fuzzy on the details, but you could choose one of a dozen destinations to write about, and the grand prize was a trip to your destination. I wanted it enough to remember that the kid who won wrote about ancient Egypt using a clever newspaper layout and style. I wrote about the Galapagos. I was already an ecologist in the making, though I didn’t discover it as a field of study until my junior year of college.

Ecologists want to understand how plants and animals respond to and within their environments. Why ecology? First, I’m insatiably curious, a skeptic, and I find asking questions infinitely more interesting than knowing the answers. Second, I’m a big-picture person who sometimes struggles with details. Working like a bookkeeper is the hardest part of the scientist’s triangle for me. Third, the natural world never ceases to amaze me, whether it is my back yard or the Galapagos Islands. The mysteries are what make it so compelling.

Ecology asks the big-picture questions that continually inspire me. While the concepts are intuitive, ecology demands that you draw together all the knowledge you have to explain something you’re witnessing in nature.

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It’s that intuitiveness about ecology that makes it so much fun to share with others. There’s nothing like an octopus video to get everyone in the room squealing–indeed, this happened two weeks ago in Science Olympiad, with the kids AND the parents. Yet, science is undergoing a crisis because of our inability to communicate (a future post and something I’ve ranted about for years). I’m trained as a scientist, but my ability to communicate has landed me most of my opportunities.

The complexity of nature and ecology bogs people down. We seek the simplest explanation, which is not always the best or most complete one. However, I find that stories and tidbits of information get us all thinking about bigger ideas. When I posted a compelling photograph of the Table Rock fire and a short explanation about fire ecology on Facebook, I received many positive comments from friends of all ages and backgrounds, that they had learned something new and interesting.

Following the Table Mountain fire in Linville Gorge. The photos look scary (and beautiful), but the montane pine forest and woodland that rims the gorge is adapted for stand-replacing fires like this one. I’ve been up here several times in the last few years and from an ecological perspective, this fire is just what Linville Gorge desperately needs for species like Table Mountain and pitch pine and rare species like Greenland sandwort and mountain golden heather. In fact, the USFS has a proposal on the table to use prescribed fire in Linville Gorge for this very reason. How this fire plays out–both from a PR perspective as well as ecologically–is going to dictate this conversation, and future conversations, on burning in this wilderness area. I hope that it burns and that the public will see the benefits. 

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To that end, I’m planning a similar exercise, one I’ve used over the years in the classroom and for fun, with friends. While in the Galapagos, I hope to post a daily photo with a caption–a great photo and a fun fact that will pique your curiosity, but one that leads you to bigger ideas and questions. I’m going where Charles Darwin noted astonishing differences in species between islands, which gave rise to his theory of evolution. The theory of evolution and understanding where species come from underpins ecology as a science. Wow!

Who is it for? Everyone: my NC State students, my colleagues, my family, my kids, my Science Olympiad team, and my friends. Stay tuned!

My students have also started a website, where they plan to post a daily blog, field guide, and video: http://ncsugalapagos2014.wordpress.com/. We’re looking forward to sharing what we’re leaning. Join us on our adventure!