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  • In physics, questions about astronomy led to revolutionaries such as Kepler and Newton,

  • who provided a new theoretical framework that replaced the old Aristotelian one.

  • But when it came to the study of living things, this shift didn't happen until a little

  • later, in the 1800s.

  • You've probably heard of Charles Darwin, but before we get to him, and I'm ecited to get to him,

  • you really need to understand how different people, throughout the seventeenth and eighteenth centuries,

  • tried to answer the same question: “what is life?”

  • [INTRO MUSIC PLAYS}

  • During the Scientific Revolution and Enlightenment, there was no biologythat term was first

  • used in 1799.

  • Instead, there was natural history, the observation-based study of living things, based on the work

  • of Aristotle.

  • For Aristotle, living things were all of one kind, but animated by different types of soul.

  • So, plants have a vegetative soul and can grow.

  • Animals have a sensitive soul and can move.

  • And humans alone have a rational soul, capable of reason.

  • Organisms could be compared by imagining their position on a great chain, leading upward

  • in complexity and worth from grass to starfish to humans.

  • This Great Chain of Being gave people throughout Europe and parts of Asia and Africa a way

  • to understand differences in form between things.

  • But it didn't include an element of time.

  • Did living things change over time?

  • That is, did they evolve?

  • What sorts of evidence would prove this, and would this proof contradict the bible?

  • Would God let extinctions happen!?

  • Let's set the stage for these questions, which would rock the world of natural history.

  • Alongside the first microscopists, other brilliant people were creating knowledge about living

  • things in the 1600s.

  • Two notable natural historians jump out—a great experimentalist and a great observer.

  • In 1634, the Spanish Inquisition arrested Flemish alchemist Joannes Baptista van Helmont

  • for the crime ofstudying plants!

  • He was put under house arrest, but this experience didn't deter him: like Galileo, it made

  • him want to science even harder.

  • Van Helmont really wanted to understand how plants grow, so he devised his famous willow

  • tree experiment to provide some answers.

  • Van Helmont wanted to test the theory that plants grow by eating soil, so he weighed

  • a willow treeit was five poundsas well as some soiltwo hundred pounds of it.

  • He planted the willow in the soil, in a pot, and then tended to the plant's needs, observing

  • its growth over five years.

  • After that time, he weighed the tree again, then dried the soil and weighed it, too.

  • The mass of the soil had remained the same over five years, but the tree's mass had

  • significantly increased.

  • Van Helmont concluded that the tree grew not by eating soil but by drinking water.

  • Published in 1648, after Van Helmont had died, this willow-weighing became the first quantitative

  • experiment in biology!

  • Another major seventeenth-century natural historian was Maria Sibylla Merian.

  • Born in Frankfurt in 1647, Merian was the leading entomologist, or insect expert, of

  • her day, as well as a highly skilled scientific illustrator.

  • Merian became well known for her work on how some insects metamorphose, or change shape.

  • Her careful observations of the life cycle of the butterfly became a benchmark for other

  • natural historians.

  • In 1699, Merian traveled to the Dutch colony of Suriname in South America to study tropical

  • insects.

  • She was horrified by the slavery she encountered there, but was also aided by an enslaved person,

  • which was typical of many European natural historians.

  • In 1705, Merian published the heavily illustrated Metamorphosis Insectorum Surinamensium, cementing

  • her reputation in both art and science.

  • The next major shift in natural history came thanks to Carl Linnaeus.

  • Born in 1707, Linnaeus sought to discover the order of nature.

  • He reasoned that, if you could just compare every species along the same axissay, sexual

  • organs, or limbsthen you could create a gigantic table, showing every living thing

  • on earth, side by side.

  • Think about that supremely Enlightenment-style visual metaphor: life was a static table full

  • of information.

  • Lots of other people were trying to figure out how to classify living things.

  • But Linnaeus's system won out.

  • Linnaeus invented the binomial system that biologists still use.

  • The first name or genus represents a more general category.

  • The second name or species is based on a specific characteristic.

  • Humans, for example, are Homo sapiens, or theintelligent men,” as opposed to our

  • extinct relatives, Homo erectus, thestanding men,” or our closest living relatives, the

  • bonobos, who some scientists classify as Homo sylvestristheforest men.”

  • Linnaeus introduced the binomial system in Systema Naturæ in 1735.

  • We can compare this text to Galileo's Two Sciences or Newton's Principia, in that

  • it provided natural historians with a new paradigm for how to do their jobs.

  • Beyond the binomial, Systema also addressed higher-level classification.

  • Say you encounter a thing.

  • First, you decide on its kingdommeaning whether it's an animal, vegetable, or mineral,

  • as per tradition.

  • Then you assign it to a class, such as such as mammal or bird, and an order based on some

  • characteristic, such as, say, eels or spiny-finned fishes.

  • FYI, Linnaeus was the first to assign bats to Team Mammal instead of Team Bird.

  • Then you assign genus and species.

  • And all of these decisions you make rationally, based on some observable and comparable feature:

  • does the thing have wings or arms?

  • Spines or no spines?

  • How many ventricles in its heart?

  • Internal or external gills?

  • Although it's evolved a lot over three centuries, we still use Linnaeus's system today!

  • Linnaeus was called theSecond Adambecause he named so many organisms, mostly

  • plants.

  • He didn't go out collecting plants, but he inspired a generation of European natural

  • historians who did.

  • They had a new tool at their disposal that allowed them to rapidly concentrate thousands

  • of botanical samples in a small number of botanical gardens: empire.

  • With tall-ships constantly sailing from London, Antwerp, Stockholm, and Calais for distant

  • continents, the naturalists of the 1700s used military might to make knowledge about ecosystems

  • that Europe didn't have.

  • A perfect example of a statesmanscientist who took advantage of colonial empire in order

  • to fill in the table of nature was Sir Joseph Banks.

  • Born in 1743, Banks became the preeminent British naturalist of his day.

  • Appointed by the Royal Navy and the Royal Society, Banks sailed with James Cook aboard

  • the HMS Endeavour from 1768 to 1771, traveling to Brazil, Tahiti, New Zealand, and Australia.

  • When he returned home, famous and full of ideas about the great variety of living things,

  • Banks became advisor to the king on the Royal Botanic Gardens at Kew.

  • He also rose to become president of the Royal Society, holding the position for over forty

  • years.

  • In order to build Kew into one of the greatest botanical gardens in the world, Banks directed

  • other botanists to travel the world, collecting plants, and bringing them back to the center

  • of the British Empire.

  • There, they were classified using the Linnaean system and shown off to the public.

  • So, Linnaeus was hugely influential in thinking about how to classify organisms, and Banks

  • pushed the powerful British Empire to make tabulating nature a project of prestige.

  • But they didn't raise deep epistemic questions about what living things are, like if species

  • change over time or not.

  • Those questions would come into the mainstream of science thanks to a trio of French thinkers

  • who we can think of as theTransformists”: Buffon, Lamarck, and Cuvier.

  • Georges-Louis Leclerc, AKA the Comte de Buffon, was born in 1707.

  • He became superintendent of the Royal Garden in Paris and argued with Thomas Jefferson

  • about whether animals and plants in the Americas were inferior to those in Eurasia.

  • (We'll come back to the Americas.)

  • But, importantly for natural history, Buffon thought that living things are degenerating,

  • or slowly becoming worse than God originally designed.

  • He didn't provide a mechanism for how this devolution worked, and he later recanted his

  • controversial views.

  • But Buffon did at least open the door among well-connected, university-trained philosophers

  • to the idea that species changed.

  • This idea was pushed further by a more humble botanist.

  • Jean-Baptiste Lamarck, born in 1744, he was a peasant, but he became a professor of invertebrates:

  • actually, he coined the terminvertebrate!”

  • Lamarck was an expert on marine worms and marine snails, mostly focused on shells.

  • Although he also published Flowers of France, in 1778.

  • And, influenced by Buffon, Lamarck criticized the fixity of Linnaeus, moving toward an evolutionary

  • theory.

  • ThoughtBubble, What did that theory look like?

  • The reason we remember Lamarck as the almost-Darwin

  • is that he developed a specific theory oftransformismeto describe how species

  • changedproviding a how and, perhaps more importantly, a why.

  • Lamarck believed that individuals inherited the traits that their parents had acquired

  • during life.

  • In life, individuals use certain body parts more than others, changing them ever so slightly,

  • and then pass those changed parts down to their kids.

  • Although this idea has been proven wrong since Lamarck's time, some historians still credit

  • him with essentially predicting epigenetics, or changes in living things made by changes

  • to which gene are expressed rather than by changing the genetic code itself.

  • Gradually, Lamarck thought, creatures would become more complex.

  • This progressive evolution was the opposite of Buffon's devolution.

  • Lamarck's famous example was the giraffe: according to Lamarck, its neck elongated as

  • the animal stretched up to reach leaves that were higher on trees.

  • Over time, short giraffes grew slightly longer and slightly longer necks untilvoilathey

  • could reach those high leaves.

  • Of course, Lamarck never actually studied or even saw a giraffealthough he almost

  • got the chance.

  • The Pasha of Egypt had given France a giraffe in 1827, shortly before Lamarck diedbut

  • after Lamarck had gone blind.

  • Lamarck's transformisme was not exactly a full framework for doing natural history.

  • But he did argue that, essentially, the environment is what pulls an organism along into a new

  • formwhich makes historiographical sense.

  • After all, Lamarck lived in a setting of rapid, radical change for humans like himself:

  • the French Revolution.

  • He saw the transition from a post-Revolution republic into the empire of Napoleon Bonaparte.

  • And he saw how different individuals responded to environmental shifts.

  • Thanks, ThoughtBubble. Finally, there was Georges Cuvier, born in

  • 1773, and he added a different wrinkle to the theory of biological transformation: extinction.

  • Cuvier was an immensely famous professor, known as theNapoleon of natural history.”

  • Cuvier met Ben Franklin, corresponded with Thomas Jefferson, and advised the real Napoleon.

  • Scientifically, Cuvier established modern comparative anatomy as a discipline, specializing

  • in the study of elephants.

  • Cuvier believed each species was perfectly adapted to its environment, and that you can

  • reconstruct an organism from only one or two bones, if you understand how anatomical systems

  • function.

  • Cuvier opposed any theory of evolution, vigorously arguing against Lamarck's progressive one.

  • But Cuvier also built his entire personal scientific empire on the careful study of

  • fossilized animal remains, comparing living and dead animals and classifying them by their

  • bone structure.

  • He could see that some types of animals simply no longer existed!

  • How did Cuvier square the fossil record with a belief in a divinely ordered, mostly unchanging

  • creation?

  • He argued for catastrophism, the idea that major changes in species come about due to

  • catastrophic eventssuch as the Flood of Noah.

  • At the end of the 1700s, natural historians had a system for comparing and naming everything

  • alive.

  • They had state support.

  • And they had some ideas about how life changed over time.

  • But they didn't have a new paradigm for researching this change.

  • They didn't have a biology.

  • Next timelet's follow the fossil trail, hunt for mines, learn the true age of the

  • earth, and further clear the way for Darwin's biology: first, we need the birth of geology!

  • Crash Course History of Science is filmed in the Dr. Cheryl C. Kinney studio

  • and is made with the help of these 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

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In physics, questions about astronomy led to revolutionaries such as Kepler and Newton,

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