Darwin Day: 5 things right & wrong about Darwin's 160-year-old Theory of Evolution

Today marks 210 years since Charles Darwin, the legendary naturalist, geologist & biologist was born.

Today marks 210 years since the birth of Charles Darwin, a legendary naturalist, geologist and biologist.

Darwin's most noted work is on the theory of evolution by a process called natural selection. His Theory of Evolution by natural selection came into the world in 1859 in Darwin’s book "On the Origin of Species." The book describes how living things change over time because of changes in physical or behavioral traits that they inherit.

When Darwin proposed the Theory in Britain, it pissed off the country's religious establishment. Many religious folks around the world passionately argue for creationism, better known as divine creation. India worships a collection of millions of Gods across different religions. While that's an incredible amount of diversity in belief, it comes with some struggles, like the scientific illiteracy we're seeing today at the level of national science events like the India Science Congress.

Keeping that in mind, here's a collection of five facts on Darwin Day that the scientist got right and wrong in his legendary Theory of Evolution.

Correct: How natural selection works within a species

Changes that animals in a species go through don't happen overnight, but they do happen in the span of a single generation. The evolved animal is technically different from its parent, but it still the same species. It replaces the previous version of the species, much like a software update would.

With the main goal being 'survival', some of these changes help the goal (and survive over generations), and some of them don't help survival at all (and fade away from the species over time). After hundreds of generations, the species won't be the same, but it also won't be a new species, just a survivor from the same species as hundreds of years ago.

An illustration of our evolution from organic molecules. Image courtesy: Answering Genesis

Incorrect: Earth’s age

When Darwin's Theory was first published, it was the Bible and not fossil data that was widely seen as the authority on the Earth's age. The Earth was thought to be just 6,000 years old in the 19th century, which Darwin thought was too little time for all the diverse species on Earth to come to be.

But just years later, in the 1860s, geologists and astronomers came up with a scientific estimate: the Earth is somewhere between tens and a hundred million years old. To Darwin, this seemed like a reasonable amount of time for life on Earth to evolve to its current form. We know today that those calculations of Earth's age are off by 4.5 billion years. The Earth is roughly 4.6 billion years old based on research since Darwin's time.

Right: Natural selection creates new species

The diversity of flora and fauna on Earth today is because along the course of history, many new species sprouted from related one. This new species will have unique traits that make it different from its relatives. This is particularly common in one or more groups of animals that get separated or isolated from the rest of their herd for many generations.

The same species under different conditions will be exposed to different environments and adapt accordingly. So, while an elephant in Africa has larger ears so it loses more heat from its body surface, Indian elephants don't have this adaptation. At some point in their evolution, the two separated clans will have enough differences to become incompatible. They will no longer be able to breed with each other as their ancestors once did.

The peppered moth (Biston betularia) camouflaged on the bark of an oak tree was the classic example Darwin used for his Natural Selection theory_YourGenomeThe peppered moth (Biston betularia) camouflaged on the bark of an oak tree was the classic example Darwin used for his Natural Selection theory. Image courtesy: YourGenome

The peppered moth (Biston betularia) camouflaged on the bark of an oak tree was the classic example Darwin used to explain natural selection. Image courtesy: YourGenome

Incorrect: Variation between individuals in a population

Though Darwin's Theory about evolution and natural selection was spot-on about most things, he followed it up with a theory on "Pangenesis". Pangenesis tries to explain the variation in traits from one individual to the next in a single species.

Darwin proposed that cells produced seeds, called 'gemmules' that are provided by each parent. The gemmules would fuse to make an egg, which grows into a healthy functioning organism if all is well in parents' gemmules. A bad gemmule means birth defects, bad organs. He used gemmules to also explain the strength of one parent's traits over another, but no since has managed to prove his theory.

Varieties of Darwin's finches on the Galapagos island. Image: Gould

Varieties of Darwin's finches on the Galapagos island. Image: Gould

Right: Evidence of evolution

One of the hallmarks of a good theory is solid proof. Darwin looked at species of zebras in East Africa, species of finches in the Galapagos Islands. The evidence Darwin collected showed different (but closely-related) species of zebra and finches lived alongside each other during the same period on Earth. This is also something he noticed in fossils — a cluster of similar-looking animals dug up in the same layer of Earth and rock.


with inputs from Britannica and YourGenome.

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