Can Evolution Outpace Climate Change?

In sports, a slow reaction time can prove devastating for players. Think of a batter facing a pitcher’s fastball or a goalie trying to block a puck or a NASCAR driver attempting to avoid a collision. In biology, being slow to change can be devastating for a species—and the naturalistic worldview.

A research study, recently published in the British journal Proceedings of the Royal Society B, shows that a species once thought to be an efficient evolver may lack the evolutionary reaction speed to survive the current rate of temperature change occurring in its environment.¹ Such experiments on evolutionary reaction speeds not only shed light on conservation biology but may also provide important tests of competing creation/evolution models.

The species in question is a tiny tide pool copepod known as Tigriopus californicus. This creature ranges from 0.25 to 2.5 millimeters in size and feeds on microscopic algae, protists, and bacteria. An individual Tigriopus californicus has a 14-stage life cycle and can live for as many as 100 days, though the typical lifespan is 50–60 days.

Tigriopus californicus has a reputation for adaptability. It tolerates temperatures ranging from 10–35° Centigrade (50–95° Fahrenheit) and salinity levels ranging from 10–100 parts per thousand. In the Bodega Marine Laboratory at the University of California, Davis, three biologists conducted an experiment using live Tigriopus californicus specimens collected from eight different locations between Oregon and Baja California. They grew these specimens in their laboratory for ten generations. The researchers subjected the specimens and their offspring to increasing heat stress and artificially selected those that proved to be the most heat-tolerant.

The team discovered that, within each of the eight populations, they could, at best, breed only about a half-degree Celsius of increased heat tolerance over the ten generations. In four of the eight population groups, selective breeding could produce no increase in thermal tolerance beyond the fourth generation. This breeding barrier implied, in the words of the authors, that  “standing variation had already been depleted.”² These breeding limitations persisted despite the fact that individual specimens within each population group could withstand temperature swings of up to 20 degrees Celsius per day. What they could not tolerate was any significant increase in the average temperature.

This study challenged the assumption that widespread species possess a high genetic capacity to evolve in response to changes occurring in their habitats. The problem for Tigriopus californicus is that, although the species is widespread geographically, individual population groups are often confined to local rocky coastal outcrops where wave splash transports them among just a few tide pools. Thus, very little flow of genes takes place across the population as a whole.

The research team pointed out in their paper that habitat fragmentation is not limited to just species akin to Tigriopus californicus. Many different species of mammals, birds, reptiles, amphibians, and plants also experience habitat splitting. However, whereas for Tigriopus californicus the habitat fragmentation is attributable to natural phenomena alone, for several other species of plants and animals, human activity greatly enhances the level of fragmentation.

The three authors argue that environmentalists have most likely underestimated the deleterious effect of human activity on species survival. Human activity, they explain, threatens species in two ways: (1) by generating climate change; and (2) by generating habitat fragmentation. The two factors in combination imply a much higher than previously estimated mass extinction rate as a result of human activity. The authors’ study underscores just how poorly equipped the evolutionary resources (for example, natural selection, mutation, and gene exchange) of certain species may be to survive the onslaught of current environmental changes. As co-author Richard Grosberg says, “The critical point is that many organisms are already at their environmental limits, and natural selection won’t necessarily rescue them.”³  

This study yields yet one more example of how conservation biology research provides important tools for resolving creation/evolution debates. Today, no conservation biologist would doubt that we are observing in real time a species extinction rate that is orders of magnitude greater than any possibly existing species production rate. Studies like the one achieved by the UC Davis team demonstrate that the imbalance is far greater than previous estimates and is likely to become even more extreme in the near future. For a naturalistic (that is, nontheistic) evolutionary model for Earth’s life to be viable, natural species creation must exceed natural species extinction throughout the past 3.8-billion-year history of Earth’s life.

Evolutionists respond by claiming that conservation biology does not disprove their models since the current species extinction rate is not entirely natural. Human activity, they insist, has pushed the extinction rate far beyond what nature alone would generate. Creationists respond by pointing out that nature is quite capable, all by itself, of generating frequent environmental events far more impactful on species extinction than current human activity. Taking away the human factor, they explain, leaves a present environmental era that must rank as one of the most benign that life on Earth has ever experienced. As conservation biologists Paul and Anne Ehrlich pointed out many years ago, removing the human factor still leaves a presently manifested species extinction rate far higher than any presently observed or possible natural speciation rate.⁴ This disparity is especially pronounced for the more advanced species of life.

Genesis 1 and Psalm 104 answer the speciation-extinction enigma. For six creation “days” God supernaturally introduced new species of life to replace those that went extinct through natural processes. However, for the duration of the seventh day (beginning at Eve’s creation and ending with the future removal of evil), God rests or ceases from His work of creating new life-forms. That is, during the present era only natural processes are at work in the biological realm. Therefore, observing the limits of evolution during the present era and contrasting those limits with the changes and development of Earth’s life previous to the advent of humanity can put to the test competing models of creation and evolution. From a creation perspective, such comparisons can determine both the degree and the manner in which God supernaturally intervened to sustain life on Earth throughout the past 3.8 billion years.