The First Birds


Feathered flight
160 million years ago

Birds evolved from feathered dinosaurs – modern birds are essentially Velociraptors with beaks instead of snouts and wings instead of arms. The most famous early bird, Archaeopteryx, lived 150 million years ago. But in recent years slightly older fossils, such as Xiaotingia and Aurornis, have been found in China.

See other: History of Life

The Triassic Extinction


Dinosaurs unleashed
201 million years ago

The dinosaurs were flourishing on land, and in the sea giant reptiles called ichthyosaurs had become the top predators. Then another disaster struck. We’re not sure what caused the Triassic extinction, but it killed off around 80% of species. In the aftermath, the dinosaurs became the dominant land animals and eventually reached titanic sizes. The biggest species whose mass is accurately known, Dreadnoughtus schrani, weighed about 59 tonnes.

See other: History of Life

Conversations: Intelligent Design?


Helena
Here is what we know. We know that the universe is far older than the Bible suggests. We know that all complex organisms on earth, including ourselves, evolved from earlier organisms over the course of billions of years. The evidence for this is utterly overwhelming.

Sappho
For example, there is no question that the diverse life we see around us is the expression of a genetic code written in the molecule DNA, that DNA undergoes chance mutations, and that some mutations increase an organism’s odds of surviving and reproducing in a given environment. This process of mutation and natural selection has allowed isolated populations of individuals to interbreed and, over vast stretches of time, form new species. Continue reading

The First Mammals


Hairy beasts
220 million years ago

At the same time that the dinosaurs were spreading and diversifying, the first mammals evolved. Their ancestors were reptiles called cynodonts, whose faces looked a little like those of dogs and may have had fur or whiskers. Early mammals such as Morganucodon were small and shrew-like, and probably only active at night. This may have spurred them to evolve warm-bloodedness: the ability to keep their body temperature constant.

See other: History of Life

Conversations: Civilization of Ignorance


Sappho
All complex life on earth has developed from simpler life forms over billions of years. This is a fact that no longer admits of intelligent dispute. If you doubt that human beings evolved from prior species, you may as well doubt that the sun is a star.

Galene
Well, not to be facetious, but the sun doesn’t look like any other star.

Sappho
Granted, the sun doesn’t seem like an ordinary star, but we know that it is a star that just happens to be relatively close to the earth.

Helena
The point is this: imagine your potential for embarrassment if your religious faith rested on the presumption that the sun was not a star at all. Imagine millions of Christians in the United States spending hundreds of millions of dollars each year to battle the godless astronomers and astrophysicists on this point. Imagine them working passionately to get their unfounded notions about the sun taught in our nation’s schools. This is exactly the situation Christians are now in with respect to evolution. Continue reading

The Great Dying


Permian extinction
252 million years ago

Just as the reptiles were flourishing, life on Earth faced perhaps its greatest challenge. The Permian extinction was the worst mass extinction in the planet’s history, obliterating up to 96% of marine species and similar numbers of land animals. We don’t know for sure what caused it, but massive volcanic eruptions – creating what is now the Siberian Traps – may have been to blame. In the aftermath, the first dinosaurs evolved.

See other: History of Life

Pangaea


Supercontinent
300 million years ago

For the last time, all Earth’s continents came together to form one giant supercontinent. Known as Pangaea, it was surrounded by a world-spanning ocean called Panthalassa. It lasted until 175 million years ago, when it began to tear itself apart over tens of millions of years. Its shattered remnants became the familiar modern continents.

See other: History of Life