Great IdeasNature and science
Plants and animals
Living things: their parts, their growth and their kinds.
The question
What makes something alive? How are plants and animals built, and how do they grow?
How the books answer
Oldest first. Each stop is our own short summary of what the author argued; follow the link to the rung for the whole lesson.
c. 350–322 BC
Aristotle, History of Animals, Parts of Animals, Motion and Gait of Animals, Generation of Animals
Aristotle was the first great biologist. He sorted hundreds of animals by their parts and ways of life, and noticed that dolphins breathe air and feed their young with milk like land mammals. He urged students not to turn away from studying even humble creatures.
“Every realm of nature is marvellous.”
c. 39–29 BC
Virgil, Eclogues and Georgics
Virgil's Georgics is a poem about farming: plowing, vines, cattle and bees. He describes the bee colony with love and wonder, as a little city. It mixes real farm knowledge with old beliefs, and praises honest work on the land.
late 2nd century AD
Galen, On the Natural Faculties
Galen says growth and nutrition are shared by plants and animals, while feeling and voluntary motion belong to animals alone. He explains living processes by faculties, powers of attraction, holding, changing and expelling. It was an early attempt at a general physiology.
1651
William Harvey, On the Generation of Animals
Harvey watches chicks form in the egg and deer embryos develop. He argues that the parts of an animal form gradually, one after another, not all at once in miniature. His motto was that all animals come from an egg.
1790
Immanuel Kant, The Critique of Judgment
Kant notices that living things are unlike machines. In an organism, each part both serves and is made by the whole, as a tree's leaves feed the tree that grows them. We cannot help thinking of living things as having purposes, he says, even when we study them as nature.
1851
Herman Melville, Moby-Dick
In the middle of his adventure, Melville's narrator stops to catalog whales, their skeletons, their size and how whalers hunt them. Some of it is good natural history and some is out of date even for his time (he insists the whale is a fish). The whale remains a wonder beyond full understanding.
1859
Charles Darwin, On the Origin of Species
Darwin argues that all living things are related, changing slowly over many generations. Individuals vary, more are born than can survive, and those with helpful traits leave more offspring. He ends by calling the tangled web of life a grand view.
1944
Erwin Schrödinger, What Is Life?
Schrödinger, a physicist, asks how living things keep their order when everything else runs down. He guesses that genes are a kind of code written in a special molecule. His little book inspired scientists who later found the structure of DNA.
1961
C. H. Waddington, The Nature of Life
Waddington describes how a single fertilized egg becomes a whole animal with many kinds of cells. Genes must be switched on and off at the right times and places. He pictured development as a ball rolling down a landscape of valleys toward different fates.
For young readers
Living things grow, eat, breathe and make more of their kind. A rock doesn't do that, but a flower, a frog and you do!
Aristotle studied animals so carefully 2,300 years ago that he noticed dolphins breathe air like we do. Try being a naturalist: watch a bird, an ant or a plant for ten minutes and write down everything you see.
Talk about it
- What is the difference between a living thing and a machine?
- Aristotle said even small creatures are marvelous. What's a small creature you think is amazing?
- Watch a seed sprout in a wet paper towel. What happens first?
- Why do you think Virgil compared bees to a city?
Where else on the site
- The Characteristics of Life
- From Domain to Species
- Vertebrate Groups
- Bees, Butterflies and Pollen
- The Life Cycle of a Chicken
- The Structure of DNA
Every rung tagged with this idea:
These pages are our own short synthesis, written for families. They were inspired by Mortimer J. Adler's Syntopicon, the index of great ideas in volumes 1 and 2 of Great Books of the Western World, but the questions, summaries and groupings are ours, not the Syntopicon's. Short excerpts come from public-domain translations, credited where they appear.