Understanding Earth’s geological age and evolution linked

Scientists in Charles Darwin’s time had none of today’s radiometric dating technology to help gauge the Earth’s age.

The most widely accepted beliefs while Darwin was writing his “On the Origin of the Species” were off more than 4 billion years from today’s scientifically accepted estimates.

Imagine the headaches this caused for Darwin as he tried to fit his theory of evolution by natural selection into a time frame that held the planet to be only 20 million to 100 million years old.

Well, it turns out that understanding the age of the Earth still is a key to understanding and accepting human evolution, according to research by University of Minnesota biologists.

And, like evolution itself, the age question still is contentious.

High school and college students who understand the Earth’s geological age — 4.5 billion years — are much more likely to understand evolution, the Minnesota researchers report in the March issue of the journal Evolution. The research team included biology professors Sehoya Cotner and Randy Moore as well as D. Christopher Brooks of the university’s Office of Information Technology.

The researchers surveyed 400 students enrolled in several sections of a U of M introductory biology course for non-majors. They asked about knowledge of evolution, the Earth’s age and whether students were taught evolution or creationism in high school as well as questions about religious and political views. 

Students who understood the Earth to be billions of years old were more likely to know something about evolution and understand it.

“The role of the Earth’s age is a key variable that we can use to improve education about evolution, which is important because it is the unifying principle of biology,” Cotner said in a statement about the findings.

The authors acknowledge that the age question ties into a boiling stew of belief differences that relate to religion and politics. 

“A vocal group of citizens and religious activists continue to insist that Earth is less than 10,000 years old,” they said.

They cite data from several polls showing that a good share of the public — and, even biology teachers and majors — buy into anti-Darwinian views and young-Earth theory:

• A Gallup Poll conducted last year amid the widely-noted celebration of Darwin’s 200^th birthday, found that only four in 10 Americans believe in evolution.

• Another study in 2008 reported that 16 percent of biology teachers believed that human beings were created by God in their present form within the last 10,000 years.

• A similar percentage of biology majors consider themselves to be “young-Earth creationists,” a view that generally holds the Earth to be less than 10,000 years old.

They also note that far less funding goes to the National Center for Science Education than to institutions promoting creationism such as the Answers in Genesis Creation Museum in Kentucky, which says on its web site that it “counters evolutionary natural history museums that turn minds against Scripture.”

In Darwin’s age, the conflicting views were coming from other scientists.

“The most widely accepted estimates of Earth’s age were those of William Thomson (later Lord Kelvin),” the Minnesota researchers said. “Kelvin used calculations involving thermodynamics to argue that Earth is only 20-100 million years old — an age far too brief to accommodate evolution by natural selection.”

Understanding that the history of life on Earth ultimately relies on geology, Darwin referred to Thomson’s claim as one of his “sorest troubles.”

“Darwin suspected that Earth was much older than Thomson claimed, but

Thomson’s enormous stature as a scientist obliged Darwin to reconcile his claims with Kelvin’s data,” they said.

To accommodate Kelvin’s timeline, Darwin proposed an explanation of inheritance that eventually was proved wrong.

“Clearly, Earth’s age remains one of the “sorest troubles” for many people today, just as it did for Darwin,” they said.