Although intelligent design is evident in the biochemistry of the cell and the physiological systems of the body, living organisms are not independent but exist in a web of life, interdependent upon other living things in an ecosystem.  

As we think about all the species of animals, birds, and fishes on Earth, it becomes apparent that each one requires a certain type of food, suitable for its anatomy. Domestic livestock, including cattle, horses, sheep, and goats, can be nourished through grazing on grasses and broadleaf weeds, although each has different preferences.¹ Among the wild animals, carnivores have varying needs for prey that match their size and abilities. With the thousands of species of birds, the preferred menu selections stretch from sips of nectar to berries, insects, smaller animals, carrion, or fish.

Variety and Quantity

Considering that water covers 71 percent of the Earth’s surface, it’s not surprising that the variety and quantity of fish inhabiting oceanic and freshwater ecosystems is legion.

The total number of living fish species — about 32,000 — is greater than the total of all other vertebrate species (amphibians, reptiles, birds, and mammals) combined.²

Fish species include herbivores and carnivores (smaller fish get eaten by bigger fish). The largest marine species include baleen whales that are uniquely outfitted to obtain their nourishment from the smallest organisms:

[Baleen whales] are the largest animals on Earth, yet they live off some of the smallest. They can grow to lengths of 30 meters (90 feet), but it is the microscopic zooplankton, krill and small fish that sustains them.³

The main point here is not a lesson on what different creatures eat, but that the multiplied billions of creatures on Earth all need to be fed according to their specific dietary needs and their physiological and anatomical specifications. Anyone who has taken care of animals knows that concern over providing sufficient food of the right type never takes a vacation. Not many of us have pet hummingbirds, but if we did, we might lose weight just making sure they didn’t:

Hummingbirds have a very high metabolism and must eat all day long just to survive. They consume about half their body weight in bugs and nectar, feeding every 10-15 minutes and visiting 1,000-2,000 flowers throughout the day.⁴

Caring for more prosaic animals is also demanding:

Cows are natural grazers, preferring to eat 5 to 9 meals a day, plus drinking. For this reason, cows have free access to fresh food and water throughout the day….So just how much does a cow eat? While each cow is different, a typical milk-producing dairy cow, weighing around 600kg, eats around 29kg [64 pounds] of feed each day and may drink about 100L of water (about a bathtub’s worth).

Apart from domesticated animals, wildlife depends upon an ecosystem in which the lives of multiple species are interconnected. We can observe how many species of living things thrive in a given ecosystem, but to take for granted the finely tuned balance within these life-nourishing habitats is to overlook layered evidence for design.

Let’s Look at a Few Specific Examples

In the wild, an apex predator such as a lion is equipped to hunt prey, but of course an abundance of suitable prey must exist within its territory. The prey, typically herbivores, need sufficient grassland to graze upon and water to drink. Seasonal weather changes must be moderate, so that vegetation and surface water are available year-round. The perspective of naturalism takes it for granted that these requirements are simply adaptations that occurred in time and location without any thought or foresight.

Consider another example. A raptor such as a red-tailed hawk is equipped with the ability of flight, sight and talons to hunt and capture small creatures. Rather than ascribing the sophisticated, finely tuned characteristics of such a bird of prey and its ecosystem to unguided evolutionary adaptations, purposeful design provides an explanation more consistent with the specific, interdependent functionality in this and other examples.

Design or Adaptation?

Surviving a cold winter that can last four to six months or longer, when no plant growth occurs and insects vanish, would seem impossible for many types of birds. However, several species of songbirds manage just fine, even when the average temperature falls well below freezing, eating seeds, nuts, and berries. Is this evidence for design, or is it just natural adaptation? 

If the ability of birds to thrive across the Earth is just a matter of adaptation, the process works unbelievably well with the thousands of species of birds. “New research estimates there are between 50 billion and 430 billion birds on Earth.”⁵ The sheer number and variety of birds thriving in multiple environments on every continent argues that something far more than luck and unguided nature is behind it all.

Our increased understanding of the biochemical complexity within any living organism, coupled with a growing awareness of the delicately balanced ecosystems sustaining life on Earth, suggest ingenious foresight, planning, and design with every type of life we observe.⁶

Fish far outnumber birds on our planet, with estimates of 3.5 trillion fish inhabiting the oceans,⁷ and each one of these trillions of creatures needs a regular supply of food accessible to it in a suitable form and quantity. Let’s imagine an experiment: given a planet with oceans empty of life, how much intelligence would it take to design an interdependent ecosystem capable of supporting thousands of species of fish over a time frame stretching across hundreds of millions of years? 

From Molecules to Gills

Oh, and if you, as a designer substitute, think of a type of fish to introduce into the pond, you’ll have to design everything about it, from molecules to gills. “Trial and error will save the day!” you say? “Once life gets going as a single-cell organism, chance and natural selection will succeed where human intelligence falls short.” Ah, yes. That makes sense.

Notes

1.  “Understanding Working Rangelands — Cattle, Sheep, Goats, and Horses: What’s the Difference for Working Rangelands?” Univ. of California, Agriculture and Natural Resources, publ. 8524 (July, 2015).
2. https://www.nationalgeographic.com/animals/fish .
3. Jon Lapidese, “Baleen Whales — The Gentle Giants of the Ocean,” https://oceanwide-expeditions.com/blog/baleen-whales-the-gentle-giants-of-the-ocean
4. https://www.adirondackcouncil.org/page/blog-139/news/10-facts-about-hummingbirds–and-other-interesting-tidbits-1101.html .
5. How many birds are there in the world? | National Geographic .
6. Marcos Eberlin, Foresight: How the Chemistry of Life Reveals Planning and Purpose, https://www.discovery.org/store/product/foresight/ .
7. “How Many Fish Live in the Ocean?” WorldAtlas.