Ernst Mayr: Biography, Theory & Contributions

Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

'The Darwin of the 20th century,' Ernst Mayr continues to be an influential and important evolutionary biologist. In this lesson, you'll learn about Mayr, his achievements, his theory on speciation, and check out some of his famous quotes.

Who is Ernst Mayr?

You have likely heard of Charles Darwin, considered the father of evolution for his well-known theory involving natural selection. You also likely recognize the name of his famous book on this topic, On the Origin of Species.

But what about Ernst Mayr? Are you able to rattle off his famous evolutionary theory and book? By the end of this lesson, you will be able to do just that! And you'll wonder how you never knew it before.

The Life of Ernst Mayr

Ernst Mayr was born in Kempten, Germany in 1904. He had two brothers, and his father died when he was just 13 years old. As a child, Mayr's parents would take the kids on long nature hikes where they could explore and learn about the natural world. It was on these hikes that Mayr discovered his love of ornithology, or the study of birds. In fact, by the age of 10, Mayr could identify all the local birds by both sight and sound!

Ernst Mayr is considered one of the most important evolutionary biologists
Biologist Ernst Mayr

Mayr initially focused his studies in medicine, but at 19 years old was convinced to switch to biology. This is when he also published his first of over 700 papers. He also published 25 books, the last of which was published only shortly before he died in 2005 at the age of 100.

Having a similar interest as Darwin in studying and collecting specimens, from 1928 - 1930, Mayr went on three excursions to New Guinea and the Solomon Islands. Mayr's excursions came roughly 100 years after Darwin's famous specimen study expedition!

In 1930, after these expeditions, Mayr moved to the United States. In 1942, he published Systematics and the Origin of Species, by far his most famous book. He founded the Society for the Study of Evolution in 1949, and from 1961 - 1970 was the director of the Museum of Comparative Zoology at Harvard. He retired in 1975 but kept teaching and publishing for the rest of his life.


Now that you know who Mayr is, let's talk about why he is so special. Mayr is often called the 'Darwin of the 20th century', and is recognized as one of the greatest evolutionary biologists ever. Darwin is famous for his theory of natural selection, and even though his book is titled On the Origin of Species, Darwin struggled with the 'origin' part. And that's where Mayr comes in.

Mayr was heavily influenced by the work of Charles Darwin
Charles Darwin

It may be common knowledge to us today, but how new species come about was still a mystery at that time. Mayr was heavily influenced by Darwin's work and built on it to answer this question. What Mayr proposed was this: that when separated for long enough or by a great enough distance, a small group of individuals will eventually evolve different traits. They have been so isolated from the original group that they become their own genetically unique species.

Mayr also believed that this speciation is what leads to diversity on Earth. Recently separated species may only have small differences, but over time, those differences branch out far enough that there are unique adaptations and traits that become more distinguishable; examples include tail length, beak shape, fur color, etc.

Again, in 1942, this was very modern thinking, and Mayr was rightfully recognized for this theory. Can you see now why his famous book on this theory, Systematics and the Origin of Species, both pulls from Darwin's On the Origin of Species and helps identify the 'origin'?


Ernst Mayr is universally respected for his many contributions to the scientific world. But he is also revered for his strong belief in the principles of science, encouraging us to understand its flexibility, fallacies, and how much we may never know, although we should never stop pursuing it!

We see it here when he says: 'Evolution as such is no longer a theory for a modern author. It is as much a fact as that the earth revolves around the sun.'

Or when he says: 'Our understanding of the world is achieved more effectively by conceptual improvements than by discovery of new facts,' encouraging us to think about the big picture

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