Ecology: Crash Course History of Science #38

By | December 3, 2019


We’ve explored the origins of modern biology,
the earth sciences, and even the sciences of outer space. Now it’s time to put these disciplines together. Starting around 1900—but picking up during
the Cold War—scientists looked beyond individual species and ask questions about how whole
systems of living and nonliving things change together over time. Where geneticists looked to model evolution
in the laboratory, these nature-focused, systems-thinking scientists looked to bring laboratory-style
research—meaning reproducible and empirical—into the literal field. It’s the birth of ecology and earth systems
science! [Intro Music Plays] As with other “modern” disciplines, ecology has lots of roots in different places and
times, but it became a formal science in the late 1800s and early 1900s. The detailed, wide-ranging, and data-driven
work of Darwin, Wallace and others inspired other life science researchers to travel and
observe the complexities of the living world. And Darwin’s German hype-man, biologist
Ernst Haeckel, coined the word ecology, This means the study of the
oikos, meaning home—or, metaphorically, the environment. Haeckel introduced popular readers to many
environments in his masterwork of scientific illustration, Art Forms in Nature. But okay—what exactly would doing a science
of the environment look like? It would involve studying life and the nonliving
things that affect life like water and soil. Mediating between living and nonliving things
are nutrients like carbon, nitrogen, and oxygen, which cycle in and out of organisms in different
ways. So early ecologists tended to include both
life scientists like Haeckel and earth scientists; as well as those studying evolution, like
geneticists working on flies, and those studying landscapes, like botanists. Botanical gardens remained key places to conduct
research, as did natural history museums that collected bones, fossils, and preserved specimens
in jars. Bones could be compared to bones, leaves to
leaves, and so on. Mexican-American Ynes Mexia started fieldwork
at the age of fifty one… and went on to collect more than 150,000 wild botanical specimens,
at least five hundred of which were new species. And her work is still being processed! Meanwhile, Russian-Ukrainian polymath Vladimir
Vernadsky pioneered ways to analyze nature holistically. One was geochemistry, or using the methods
of chemistry to understand minerals. Another was biogeochemistry, which analyzes
living and nonliving processes. Vernadsky promoted a new mode of ecological
thought: what is life? At the highest level of analysis, it’s the
whole observable-by-humans planet! The nonliving, or abiotic, dimension of the
earth is the geosphere, which cradles and interacts with the biosphere. Vernadsky even proposed another level: the
noösphere, or totality of human thought, which he imagined cradled
by and interacting with the lower levels. Vernadsky also pioneered radiogeology, the
study of radioactive elements in the crust. Aaand he worked on the Soviets’ atomic bomb. Because sooooo many scientists worked on weapons. Around the time that Vernadsky worked, ecology became a discipline. English botanist Arthur Tansley first obsessed
over ferns, and later all plants. He wanted to map all of the different types
of vegetation across England, and he thought other botanists should want the same. So he founded clubs to map plant types. And in 1913, Tansley organized the first professional
society of ecologists, and he became the first editor of the Journal of Ecology. In terms of epistemic work, Tansley is remembered
for one word: ecosystem. See, scientists are pretty into units. Tansley reframed the study of nature: instead
of groups of individual living things—say, some birds in some trees—it’s the study
of dynamic interactions between living and nonliving things in one area. Tansley’s rival was American botanist Frederic
Clements. His epistemic contributions similarly involved
what ecologists should study. Clements argued that plant formations are
best studied as units called communities. A plant community is not just like a living
organism: it is an organism! It’s born, grows, eats, and dies. And Clements focused on how an area’s climate
determined which plants will grow there. For example, a pond dries up over and becomes
first a meadow, then a forest. This was a version of an older concept, ecological
succession, how the makeup of groups of organisms in areas change over time. But Clements championed his own, highly deterministic
“climax community” version of succession. Tansley haaated this, arguing that nature
is messier than Clements described in his work. Tansley and Clements fought about ecology
from 1905 until World War Two. But both agreed that ecologists should promote
conservation, or working to actively maintain the health of nonhuman environments. Conservation has its own history. But ecology as a way of making knowledge has
always been tied to conservation as an ethos or practice—a way of doing something in
the world. This isn’t a “technology” in the same
way the lightbulb or computer is. But the practice of conserving ecosystems
is as important as lighting up cities or making sicc memes. To name just two wins in conservation, U.S.
President Teddy Roosevelt created the National Park system in the first decade of the 1900s,
helping preserve vast areas of forest, desert, and other wilderness. And in 1972, the Marine Mammal Protection
Act helped radically lessen the threat humans present to dolphins, seals, and whales in
U.S. waters—although the threat remains. But early ecologists didn’t have all the tools they needed. For many of those, we can thank English-American
polymath George Evelyn Hutchinson, his student, Howard T. Odum, and Howard’s older brother,
Eugene. Take us there, Thoughtbubble!
After World War Two, they established ecosystem ecology as a richly quantitative discipline. They took Tansley’s essential insight and
ran with it, showing how to model the processes at work in a given ecosystem. All three men used experiments to generate
mathematical models tracing the flow of energy from nonliving sources, into primary producers
like plants, primary consumers like herbivores, and then into meat eaters and the eaters of
dead things—fungi and bacteria. And he was the first to use very small amounts
of radioactive particles as tracers to map how particles move in a pond, including how
plants take up radiation. The Odums went on to develop this radiotracer-as-tool
technique further, which is used today to study how water moves and how pollutants move
through environments. They also helped establish radiation ecology,
which studies the effects of radioactive materials on living systems. The Odums researched ecosystems from coral
reefs in the Pacific to riversheds in Georgia. Eugene Odum taught at the University of Georgia,
in fact, from 1940 to 2002. He pushed all biology students to study ecology—which
got a big laugh in the forties, but is now part of the common sense of the life sciences. Of course you have to study how weather, plants,
animals, and soils relate! And Eugene deftly summarized, with some help
from his bro, much of their work in the book Fundamentals in Ecology in 1953. This book unified ecology, offering a range
of useful techniques to all budding plant scientists, animal scientists, and rock scientists. For years, it was the only textbook in ecology. And, revised, it’s still used as a textbook
in many classes today! Thanks ThoughtBubble!
The Odums’ work encompassed observational and empirical methods, some of which were
focused on specific parts of ecosystems. But the Odums were also pioneers of a sub-discipline of ecosystem ecology, confusingly called systems ecology. This is the holistic study of complex living
systems as systems—including the interactions among their nonliving inputs, their boundaries,
how they adapt to new conditions, how they interact with other systems, and the unpredictable,
emergent properties they exhibit. Inspired by Hutchinson’s work on feedback
loops, Howard modeled how energy flows within ecosystems. He borrowed concepts from thermodynamics and
computing in his work on systems ecology. You could say the Odums were trying to understand
ecosystems as really complex, but not random, machines. In fact, in the 1960s, they applied multiple
times for money from NASA to engineer self-regulating, closed ecosystems of algae and plankton—a
whole biosphere in miniature. These would serve as life-support systems
for astronauts. They based their proposals on their study
of the energy flows of the coral atoll Enewetak in the Marshall Islands. Alas, NASA thought their plans were too complex,
and the Odums returned to earthly matters. The question of life in space intrigued scientists modeling the relationships between energy,
chemicals, and organisms. In the 1960s, NASA hired English scientist
James Lovelock to build instruments to analyze the atmosphere of Mars—and look for signs
of life. Lovelock thought about why Mars’ atmosphere
has certain properties, different from ours, and what that means for the evolution of life. He arrived at the Gaia Hypothesis, named after
the Greek earth goddess. This says the earth’s biogeosphere is self-regulating,
within broad limits: living things, air, rocks, and water interact in complex ways so that
living things can stick around. This was a hugely controversial claim! It suggested a self-awareness to the earth. But Lovelock’s evidence for a regulatory
function between what’s in the atmosphere and oceans and what’s alive, breathing that
air or water, is pretty convincing. And he picked up major support from revolutionary
biologist Lynn Margulis. She discovered that some of the tiny organs
inside cells—like cells’ power stations, mitochondria and chloroplasts—used to be
free-floating bacteria that evolved to live entirely within larger organisms. This idea, endosymbiosis, was also huge controversial—not
because it was too touchy-feely, but because it seemed to have nothing to do with the work
of Darwin! But Margulis also demonstrated lots of evidence. So biologists and ecologists were confronted
with complex systems over here, superorganisms over there— communitiesall the way up, and all the way down in scale. Today, this shift is captured in the name
of the meta-discipline that applies systems thinking across many sciences: earth systems
science. This means understanding how living and nonliving
processes relate, and looking at the entire earth as one very big—but not infinite—house. This is a house we humans can wreck. And—we hope—repair. So just as the life sciences had to scale
up to ecosystems and then the entire earth, they also had to take into account how humans
affect ecosystems and earth systems. A new branch, human ecology, developed. If that all sounds a bit like what Vernadsky
said a hundred years ago—you’re right! Human thought, nonhuman life, rocks, water—all
connected. Or, as Eugene Odum wrote: “the landscape
is not just a supply depot but is also the oikos —the home—in which
we must live.” Next time—we’ll move from studying nature
to controlling it… and losing control. It’s time for the Green Revolution, pesticide
pollution, and the birth of environmentalism. Crash Course History of Science is filmed
in the Dr. Cheryl C. Kinney studio in Missoula, Montana and it’s made with the help of all
this nice people and our animation team is Thought Cafe. Crash Course is a Complexly production. If you wanna keep imagining the world complexly
with us, you can check out some of our other channels like The Art Assignment, Nature League,
and Scishow Space.

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