The Rise of C4 Plants

By Kevin McFadden

Imagine a happy place where you’re laying out in the Caribbean sunshine on a beach with a mojito in hand. You jump into the crystal clear blue bathwater of the sea, then you lay down in your chair under an umbrella and doze off thinking about delicate and beautiful New England winters… you wake up and look over at a little saltbush that hasn’t been consuming delicious beverages, cooling off in the sea or taken cover under an umbrella to take a nap. In fact, this poor plant hasn’t moved an inch. First off, let’s hold the phone here. The truth is, this plant is loving life and it took over 3 billion years of evolution for it to become so happy! Saltbush is one of many plants who has adapted to warm, sunny, and dry conditions.

Long ago, when atmospheric carbon dioxide levels were high and oxygen levels were low, an enzyme called Rubisco started being made in plants which is an important driver in the Calvin cycle, without which food can not be made. Continue reading

Tree migrations: a matter of scale

By Benjamin Seliger

In everyday life, trees may appear as stationary, permanent fixtures of the landscape, but in reality they are far from it. I will argue that all trees are constantly migrating, and summarize the means by which they do so in this post.

When I tell people I study tree migration, I often get funny looks. After all, how can an organism that cannot even move migrate? The answer to this, like many other phenomena in ecology, is time. Every year, mature trees release thousands of seeds in all directions, and when one of those seeds grows into an adult in a place where others of its own kind were not growing before, the species is migrating. Note that this perspective of migration is not limited to the cyclical movement of animals with the seasons, but rather an adjustment of a species’ range to preferred conditions as climate changes. I will refer to the latter as a range migration and the former as a seasonal migration. The two definitions are really explaining the same process at different scales; seasonal migration being the movement of individuals within their lifespan, and range migration as the movement of populations over the course of multiple generations. The end result for either definition is all the members of a species living in a different place than they did previously due to a change in environmental conditions. Continue reading

Humans: where we have been and where are we going

By Gloria Lima

When looking at how humans have change throughout the year one may simply think in the past hundred years or maybe even a bit further to medieval times or to ancient Rome and Greece. But nonetheless, humans have been around for longer than that– try around 100,000 years! To understand the idea that human ancestors may have been around longer than today’s humans have though is a bit mind blowing.  To think that we have been on this earth for that long is pretty amazing.  Continue reading

The Great American Biotic Interchange: The Forgotten Bird

By Wayne Heideman

Do you remember what it was like on your first day of kindergarten, college, or work? You were placed into an environment that was different than the one you had known previously, whether it was because of the people, place, or experiences. Around 3.1 million years ago, this is what North America and South America, provided they had feelings, would have felt when they became connected via the Panama isthmus. Not only did it connect two continents, but it connected the organisms that inhabited the two continents.

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Wildfire through time: shaped by climate and people

By Dulcinea Groff

Picture the landscape of a tropical savanna, composed of grasses, shrubs and a sparse number of trees.  The savanna biome is dominated by a wet season supplying thousands of herbivores with forage and a dry season accompanied by intense lightning and fire.  These wildfires maintain the savanna as grassland by killing the saplings (suppressing tree growth) and the grasses quickly regenerate.  Imagine early hominids in the fire-constructed savanna, they begin to use fire, control fire and even make it!  Fire is a permanent link now between biome and human.

Fire was used by humans for presumably many reasons:  communication, prepare food, drive and corral prey, warmth during cold periods, etc.  Humans have long suppressed and ignited fires for various reasons.  In fact, as a source of ignition, humans have been shaping landscapes since the earliest known hominids were thought to use fire one million years ago in South Africa (Berna et al. 2012). Continue reading