In the 19th century, a quiet, curious naturalist named Charles Darwin proposed a theory that went on the shake science, religion, and philosophy. Darwin introduced a new way of thinking about life itself.
His theory of evolution by natural selection revealed that every species (humans included) changes over time, adapts to its environment, and shares common ancestors.
In todayโs episode of Thinking in English, I want to explore the life of Charles Darwin, look closely at his most important discoveries, and discuss how his ideas still influence modern biology.
And finally, weโll discuss a big question: Is Charles Darwin the greatest scientist of all time?
And while we are doing this, weโll practice our English listening comprehension and learn some new English vocabulary!
Listen Here!
Apple Podcasts
Spotify
YouTubeInteractive Transcript!
You Can Now Read and Listen at the Same Time With an Interactive Transcript!
Vocabulary
- evolution (n): the gradual change of species over time.
- Evolution explains how modern birds developed from ancient reptiles.
- natural selection (n): the process where organisms with helpful traits survive and reproduce.
- Natural selection allows faster animals to escape predators and pass on their genes.
- species (n): a group of similar organisms that can reproduce together.
- Humans and chimpanzees are different species.
- ancestor (n): an earlier living form from which others evolved.
- Scientists believe that all modern whales share a land-dwelling ancestor.
- adaptation (n): a feature that helps an organism survive in its environment.
- Thick fur is an adaptation that helps polar bears stay warm.
- fossil (n): preserved remains or traces of ancient life.
- The fossil of a dinosaur footprint can reveal how it walked.
- theory (n): a scientific explanation based on evidence.
- The theory of evolution is supported by fossils, genetics, and observations of nature.
Early Life of Charles Darwin
Charles Darwin was born in 1809 in Shrewsbury. Shrewsbury is a quiet market town in western England.
He grew up in a comfortable and wealthy family home surrounded by books and learning. His parents had expectations that he would become a doctor like his father. Or perhaps a clergyman in the Church of England. These were both respectable careers for a young man of his background.
But young Darwin had different interests. At medical school in Edinburgh, he quickly discovered that he hated the sight of surgery.
Remember, Darwin was alive in the 19th century and he was at medical school [00:04:00] at a time before painkillers and before anesthesia. Operations were painful and brutal, and Darwin soon realized that the medical profession wasn’t for him.
Eventually, he moved to Cambridge to prepare for a career in the church. Ironically, it was while studying theology, studying religion, at Cambridge University, not while he was a medical school student, that he discovered a passion for science and studying nature.
Darwin loved collecting insects, examining rocks, and learning about the natural world. He spent hours looking for plants and animals and was far more interested in beetles than in theology.
At Cambridge, he also met John Henslow, a respected botanist and professor. Henslow recognized Darwin’s curiosity and encouraged him to pursue his interests and study [00:05:00] nature.
The Voyage of the HMS Beagle
When he was 22 years old, Charles Darwin received an invitation to join a global expedition aboard a British Navy ship called HMS Beagle. This was thanks to the recommendation of his mentor, John Henslow.
His role on the ship was the ship’s naturalist. He was responsible for observing, collecting, and recording plants, animals, rocks, and fossils along the journey. For five years, the Beagle traveled around the world, stopping in South America, Australia, Africa, and many small islands.
When the ship stopped at a port, Darwin would spend a lot of time exploring the new landscapes, talking to local people, and carefully collecting specimens. Gradually he noticed things that changed the way he understood [00:06:00] nature and life.
In South America, Darwin found or was shown fossils from large extinct animals, such as giant armadillo-like creatures. These fossils closely resembled, looked very similar to, smaller animals still living in the region. The fossils were similar, but not identical to modern species.
Why? Why would extinct animals look like larger versions of living ones?
Darwin suspected that there was a possible connection between these animals over time. He started to consider that species might change rather than remain fixed forever.
Darwin also observed unusual patterns among living animals. In Patagonia, he encountered a type of flightless bird called a Rhea, [00:07:00] similar to an ostrich. However, he noticed that one Rhea species lived further south while a slightly different species lived further north. Again, the question arose:
Why would these closely related animals live in different regions and have slightly different appearances?
In Chile, Darwin witnessed a very powerful earthquake. The earthquake lifted parts of the land several meters high. This dramatic event revealed to Darwin that the earth is not static. The earth changes over periods of time, and sometimes this change can happen suddenly. If the land could transform over time, perhaps life could change too.
But the most influential moment of the voyage came on the Galapagos Islands, a volcanic island group near the equator. The [00:08:00] islands were home to animals, found nowhere else in the world.
Darwin studied finches, small birds with surprisingly diverse beak shapes. On one island, finches had strong, thick beaks for cracking seeds. On a different island, finches has had longer, more delicate beaks ideal for eating insects or cactus nectar.
Similarly, the giant tortoises on each island had different shell shapes, and locals could often identify a tortoise’s island simply by looking at its shell.
These details might seem small, but for Darwin, they raised some important questions.
Could different environments shape the bodies and behaviors of living creatures over time?
Darwin began to suspect that species change [00:09:00] gradually over time. They adapt to the specific conditions of their environment.
The Beagle voyage provided the observations, the evidence, and the inspiration that would eventually lead Darwin to the revolutionary Theory of Evolution.
Developing the Theory of Evolution
After returning to England in 1836, Darwin did not publish his ideas, at least not immediately. He spent more than 20 years studying plants, animals, fossils, geology, and as many scientific papers as possible. He filled notebooks with his observations and questions and ideas.
Rather than rushing to conclusions, Darwin took his time. He built a mountain of evidence to support his theory. He knew that evolution was going to be a controversial theory, so he wanted as much evidence as possible to support [00:10:00] it.
Darwin studied the work of geologists like Charles Lyell. Lyell’s work argued that the earth had changed gradually over incredibly long periods of time. Mountains rose, oceans retreated and landscapes were shaped by these slow processes.
If the earth was ancient and always changing, then the life living on earth might also change as well.
Darwin also studied selective breeding, which is a process used by farmers and animal breeders. For centuries, humans have known that choosing animals or plants with desirable traits like bigger cows or sweeter apples or faster horses, and then breeding them can change future generations.
If humans could influence how animals and plants change, then perhaps nature could do something [00:11:00] similar on its own, without human control.
A final key influence came from reading Thomas Malthus. Malthus wrote that populations grow faster than the food supply. This leads to competition and struggle for food and resources. Not every individual can survive this competition.
Darwin realized that in nature, animals and plants were also competing for limited resources. Only those animals and plants with advantages, like stronger bodies, faster reactions, better camouflage, more efficient beaks, were more likely to survive and reproduce.
Combining all of these ideas, Darwin developed the concept of natural selection.
He proposed that individuals with traits better suited to their environment are more [00:12:00] likely to survive and reproduce. Their advantages are passed on to the next generation. Over many generations, species gradually change.
Species are not fixed or created exactly as they are forever. Instead, they evolve. And their evolution is influenced by the pressures of nature. Things like your predators, climate, food sources, diseases and competition.
Those finches in the Galapagos Islands evolved differently. On the island where the food source was hard seeds and nuts, birds with thicker, stronger beaks were more successful at eating and finding food. Hence, they gradually passed on those genetics.
On the other island, where the food sources were more to do with insects and cactus nectar, birds with longer beaks tended to do better, so eventually those [00:13:00] birds developed long, thin beaks.
This was a radical idea. It explained how new species could arise. It explained why fossils resembled some living animals. It explained why similar species lived in different places. And also why the Galapagos finches had different beaks.
Nature itself, over long stretches of time, was producing the diversity of life on Earth.
Publication and Impact of ‘On the Origin of Species’
In 1858, a young naturalist named Alfred Russell Wallace sent Darwin an essay. Wallace, working completely independently in Southeast Asia, had developed a theory almost identical to Darwin’s.
It was based on the same key idea. Species evolve through natural selection.
Darwin was shocked. He had spent years building his case, his argument, but had never [00:14:00] published anything, because he wanted more evidence and more proof first. But now he risked being forgotten or overshadowed.
To avoid conflict, both men agreed to present their ideas together to a scientific community. And Darwin quickly finished his book.
The following year, in 1859, he published On The Origin of Species, one of the most influential books in the history of science. Darwin’s writing was detailed, but clear and filled with evidence from nature.
Some of his most important ideas included that all species, plants, animals, and humans as well are connected through shared ancestors. The diversity of life we see today comes from millions of years of branching evolution.
Evolution does not happen overnight. Species change slowly over long [00:15:00] periods, across countless generations.
And nature itself chooses which individuals survive and which individuals reproduce. Those with beneficial traits are more likely to pass them on shaping the species over time.
On the Origin of Species transformed biology. It provided a unifying explanation for many scientific mysteries like fossils, biodiversity, and the similarities among species.
It paved the way for modern genetics, ecology, and even parts of medicine.
But it also sparked intense controversy, especially among religious communities. Many people believe that species were fixed creations, designed exactly as they appeared.
The idea that humans might share common ancestry with other animals was shocking, even offensive [00:16:00] for some people. Darwin himself avoided discussing human evolution in detail in his book, but the implications were obvious.
Despite criticism, Darwin’s work spread rapidly. Scientists and students debated his ideas passionately. While not everyone accepted evolution immediately, Darwin had set in motion a shift, a change, in how humans understand life.
And science was never the same again.
Darwin’s Lasting Legacy
Charles Darwin’s ideas continue to influence almost every area of biology today.
His Theory of Evolution by natural selection is the foundation on which modern biology is built. Without Darwin, our understanding of life on earth would be incomplete.
Darwin, of course, worked without any knowledge of DNA or genetics. This had not been discovered yet. He could not [00:17:00] explain how traits were passed from parents to offspring.
But decades later, scientists rediscovered the work of Gregor Mendel. Mendel’s research on plants revealed the rules of inheritance. Then eventually genetic science confirmed Darwin’s theory. DNA filled the gaps in Darwin’s understanding. DNA science showed that genes change over time, and those changes can create new traits.
Together evolution and genetics created the field now known as evolutionary biology.
Darwin’s ideas also affected medicine. Understanding evolution helps doctors now explain how viruses and bacteria adapts and how cancers evolve inside our bodies.
Darwin’s work also transformed how we study ecosystems and conservation, by [00:18:00] showing that species are connected through ancestry and shaped by their environment. He helped scientists understand the delicate balance of nature.
Today, conservation efforts, including protecting endangered animals and restoring habitats, usually depends on evolutionary principles.
Darwin also changed how humans, how we think about ourselves. His theory challenged the belief that humans are different from animals. Instead, we are part of the same family.
More than 160 years after On the Origin of Species, Darwin’s theory remains one of the most powerful and tested ideas in all of science. Unlike many scientific theories that are replaced or rewritten, Darwin’s work has been consistently confirmed, strengthened and expanded.โ
Final Thought
After exploring Darwin’s life, his discovery and his enormous influence on modern science, we arrive at a big question.
Was Charles Darwin the greatest scientist of all time?
There are strong arguments in his favor. Darwin changed how we understand life. His theory of evolution by natural selection created a framework that connects every field of biology. Very few scientific ideas have transformed our understanding of the world so completely.
However, some people argue that placing Darwin at the top is very difficult. Science has many pioneers who shaped entire areas of knowledge.
Isaac Newton revolutionized physics, mathematics, and astronomy. Einstein transformed our understanding of [00:20:00] time, space, and energy. Marie Skodowska Curie changed medicine and chemistry. And people like Rosalind Franklin and others revealed the structure of DNA. Each of these scientists changed the world in their own ways.
Should the greatest scientist be the one who explains the most important aspect of reality? Or the one whose ideas affects our everyday lives?
I want to know your thoughts.
Do you think Charles Darwin is the greatest scientist of all time? Who should I cover next in this series?
Extended Vocabulary List
Become a Patreon Subscriber to Access the Extended Vocabulary List!
Vocabulary Games and Activities!
Learn and practice vocabulary from this Thinking in English episode.
Practice using 5 different study games and activities – including writing, listening, and memorisation techniques!
Flashcards
Matching Game
Learning Game
Test Yourself
Listening and Spelling
Do you want to Think in English?
I’m so excited that you found my blog and podcast!! If you donโt want to miss an article or an episode, you can subscribe to my page!
Great job, I love this episode. Many thanks to you, Tom!