Many independent measurements have established that the Earth and the universe are billions of years old. Geologists have found annual layers in glaciers that can be counted back 740,000 years. Using the known rate of change in radio-active elements (radiometric dating), some Earth rocks have been shown to be billions of years old, while the oldest solar system rocks are dated at 4.6 billion years. Astronomers use the distance to galaxies and the speed of light to calculate that the light has been traveling for billions of years. The expansion of the universe gives an age for the universe as a whole: 13.7 billion years old. (Updated April 16, 2012)

A complex biological structure with many interacting parts might appear, at first glance, as if it were originally created in its present form with all its interlocking components fully formed and intact. It doesn’t seem possible that they developed step by step via biological evolution. In Darwin’s Black Box, Michael Behe introduces a term that he and other proponents of Intelligent Design use for this concept: irreducible complexity.

Genesis 6-9 tells the fascinating story of Noah, the Ark, and the Flood. Some Christians interpret the text to mean that the biblical flood must have covered the entire globe. They also work to explain the evidence in rocks and fossils in terms of this world-wide flood. Other Christians do not feel the text requires that the flood be global, but could have covered the small region of earth known to Noah. The scientific and historical evidence does not support a global flood, but is consistent with a catastrophic regional flood. Beyond its place in history, the Genesis flood teaches us about human depravity, faith, obedience, divine judgment, grace and mercy.

Evolution is the biological model for the history of life on Earth. While some consider evolution to be equivalent to atheism, BioLogos sees evolution as a description of how God created all life. Evolution refers to descent with modification. Small modifications occur at the genetic level (in DNA) with each generation, and these genetic changes can affect how the creature interacts with its environment. Over time, accumulation of these genetic changes can alter the characteristics of the whole population, and a new species appears. Major changes in life forms take place by the same mechanism but over even longer periods of time. All life today can be traced back to a common ancestor some 3.85 billion years ago.

Scientists have found multiple lines of evidence for evolution, not just one or two. These types of evidence are independent of each other, coming from sources as different as ancient fossils and modern genetics labs. Evidence also comes from comparing the anatomy of creatures living today. All creatures with four limbs (whether mammals, birds, or reptiles) have the same bone structure in each limb, pointing to their descent from a common ancestor. More evidence comes from biogeography. Isolated islands are missing common species found on the mainland, but are filled with many unique species that can be related by a common ancestor. Finally, evidence comes from embryonic development. As an embryo of a mammal grows, its heart develops through stages similar to fish, amphibians, and reptiles. God’s creation declares the history of life in many different ways. All these ways are pointing to a consistent picture of God creating through evolution.

The “Cambrian Explosion” refers to the appearance in the fossil record of most major animal body plans about 543 million years ago. The new fossils appear in an interval of 20 million years or less. On evolutionary time scales, 20 million years is a rapid burst that appears to be inconsistent with the gradual pace of evolutionary change. However, rapid changes like this appear at other times in the fossil record, often following times of major extinction. The Cambrian Explosion does present a number of interesting and important research questions. It does not, however, challenge the fundamental correctness of the central thesis of evolution.

From all we know about the state of the Earth 3 to 4 billion years ago and what we know about the complexity of the building blocks of life — DNA, RNA, amino acids, sugars — no entirely plausible hypothesis for the spontaneous origin of life has been found. But this does not mean that supernatural activity is the only possible explanation.

A common argument against biological evolution is that the theory contradicts the second law of thermodynamics. The second law says that disorder, or entropy, always increases or stays the same over time. How then can evolution produce more complex life forms over time? The answer is that the second law is only valid in closed systems with no external sources of energy. Since the Earth receives continual energy from the Sun, the second law does not apply.

Fossils provide a unique view into the history of life by showing the forms and features of life in the past. Fossils tell us how species have changed across long periods of the Earth’s history. For instance, in 1998, scientists found a fossil showing an animal at the transition from sea creature to land creature. This tetrapod had a hand-like fin, confirming a prediction of evolutionary biology. Though the fossil record does not include every plant and animal that ever lived, it provides substantial evidence for the common descent of life via evolution. The fossil record is a remarkable gift for the study of nature.