What is the Cambrian Explosion?

The alleged Cambrian explosion is dated by secular scientist as a period 530 million years ago, lasting only a few million years, that saw the geologically abrupt appearance and diversification of most major animal groups, or phyla. This event is a "quantum jump" in the history of life, as complex animals with features like nervous systems, eyes, and articulated limbs emerged suddenly, seemingly without a long evolutionary history.

Why was the Cambrian Explosion a problem for Darwin's theory of evolution?

Charles Darwin's theory of evolution by natural selection predicted a gradual, "bottom-up" pattern of change, where small variations would accumulate over vast periods to create new species and eventually new phyla. The Cambrian explosion, however, presented a contradictory "top-down" pattern, where the major animal body plans appeared fully formed at the beginning. Darwin called this lack of transitional fossils an "inexplicable mystery" and a serious argument against his theory, but he hoped future discoveries would eventually fill in the gaps.

How did discoveries at the Burgess Shale and in China impact this mystery?

• The Burgess Shale: Discovered by Charles Doolittle Walcott, this site in the Canadian Rockies revealed thousands of exceptionally preserved fossils of soft-bodied Cambrian animals. While it offered a stunning glimpse into the ancient seas, it didn't provide the missing evolutionary links. Instead, it showcased an even greater variety of distinct body plans that appeared suddenly, making the problem of the Cambrian explosion even more pronounced.

• The Chengjiang Fossils: Found in China, these fossils were older and even better preserved than those from the Burgess Shale. This discovery further compressed the timeline of the explosion, reinforcing its suddenness and making the problem of an unguided, gradual process even more acute.

• Fossil Embryos: The discovery of microscopic, soft-bodied animal embryos in rock layers below the Cambrian strata was particularly significant. It demonstrated that conditions for preserving such delicate fossils existed during the Precambrian era. This directly challenged Darwin's "incomplete fossil record" explanation by showing that if something as fragile as an embryo could be preserved, the larger, transitional ancestors should also have been.

What is the "information problem" in explaining the Cambrian Explosion?

The sudden appearance of complex life isn't just about fossils; it's an information problem.

• New Genes and Proteins: To transition from a simple Precambrian organism to a complex Cambrian animal (like a trilobite with a brain, gut, and compound eyes), a vast amount of new genetic information would be needed. Molecular biologist Doug Axe's research is argues that the probability of random mutations generating a single new functional protein is astronomically low.

• The Body Plan Blueprint: The instructions for building a new body plan are not just in the DNA. Another level of information, acting as a "blueprint," guides the organization of cells, tissues, and organs within the embryo. Since this higher-level information is not contained in DNA, random mutations alone cannot create a new body plan, regardless of the time available.

How is intelligent design presented as the solution?

Intelligent design is the cause that produces the effects observed in the Cambrian explosion.

• Cause and Effect: It uses Charles Lyell's dictum, "the present is the key to the past," to argue that since our present-day experience shows that complex, specified information (like a blueprint or code) comes from an intelligent source, the information needed for the Cambrian animals must have had a similar origin.

• Top-Down Design: The "top-down" pattern of the Cambrian explosion—where major body plans appear first and then undergo minor variations—is compared to how human engineers design technology. This pattern is presented as a hallmark of foresight and intelligence, as it requires a high-level objective before the details are filled in.

• Hierarchical Organization: The intricate, nested hierarchy of life—from genes to proteins, cells, tissues, and organs—is also a sign of design. This type of organization is what minds do, not undirected natural processes.

*Article created with assistance of Gemini based on the documentary Darwin's Dilemma