Sharks Are Older Than Trees

Quick Answer

Sharks first appeared in the fossil record roughly 450 million years ago, with the earliest definitive shark fossils dating to about 420-440 million years ago (Late Ordovician to Silurian period). The first true trees -- plants with woody trunks, branches, and height -- did not appear until about 385-350 million years ago (Late Devonian period). Sharks predate trees by at least 50 million years. They also predate dinosaurs by about 200 million years, the first land vertebrates by about 50 million years, and the formation of Saturn's rings.

Sharks Were Here First

When the first trees pushed their roots into ancient soil and stretched their branches toward the sky roughly 385 million years ago, sharks had already been swimming in the oceans for at least 50 million years. They had already diversified into multiple species, developed sophisticated sensory systems, and become established predators in marine ecosystems.

Trees are ancient. Sharks make them look like newcomers.

To put the timeline in perspective: sharks have been around for about 450 million years. The dinosaurs appeared about 230 million years ago and went extinct 66 million years ago. Sharks predated the dinosaurs by 220 million years and outlasted them by 66 million years (and counting). The entire age of dinosaurs -- their rise, reign, and extinction -- fits within the middle third of shark history.

Modern humans, Homo sapiens, have existed for roughly 300,000 years. If you compressed shark history into a single 24-hour day, humans would appear in the final 0.05 seconds.

The Earliest Sharks

The oldest shark-like fossils are isolated scales (called denticles) found in Ordovician rocks dating to roughly 450 million years ago. These tiny tooth-like structures -- essentially the same material as shark teeth, but embedded in skin -- are characteristic of cartilaginous fish and are the earliest physical evidence of sharks in the fossil record.

The earliest recognizable shark fossils with preserved body structures date to the Late Silurian and Early Devonian periods, about 420 to 400 million years ago. Doliodus problematicus, found in New Brunswick, Canada, is one of the oldest sharks known from significant body fossils, dating to roughly 409 million years ago. It had both shark-like features (cartilaginous skeleton, tooth structure) and some more primitive characteristics.

By the Devonian period (419-358 million years ago) -- often called the "Age of Fishes" -- sharks had diversified dramatically. Species like Cladoselache, a roughly meter-long predator with a streamlined body and large eyes, were common in the seas. Cladoselache would have been recognizably shark-like to a modern observer, though it lacked some features of modern sharks (its jaws were attached differently, and it had a largely symmetrical tail rather than the upper-lobe-dominant tail of most modern species).

The First Trees

Trees, meanwhile, were a much later development in Earth's biological history.

The earliest land plants appeared about 470 million years ago, but these were small, low-growing organisms similar to modern mosses and liverworts. They had no roots, no wood, and no significant height. The first vascular plants (with internal plumbing for transporting water) appeared around 430 million years ago but were still small.

The first trees are generally identified as Archaeopteris, which appeared in the Late Devonian period around 385 million years ago. Archaeopteris was a large plant (up to 10 meters tall) with a woody trunk, branches, and fern-like leaves. It formed the first forests, which spread across parts of the supercontinent Euramerica.

Before Archaeopteris, there were some tall tree-like organisms. Wattieza, dating to about 385 million years ago and found in New York State, was a tree-fern-like plant that could reach 8 meters. And Cladoxylopsida organisms reached several meters in height in the Middle Devonian. But these lacked true wood and are not considered trees in the modern botanical sense.

Tip

The spread of the first forests had a dramatic effect on Earth's climate. Trees pull CO2 from the atmosphere and accelerate rock weathering through their root systems, both of which reduce atmospheric carbon dioxide. The Late Devonian expansion of forests is thought to have contributed to a major drop in atmospheric CO2, global cooling, and one of the largest mass extinctions in Earth's history -- the Late Devonian extinction, which killed roughly 70 percent of marine species. Sharks survived it.

Why Sharks Survived Everything

Over their 450-million-year history, sharks have survived at least five mass extinction events:

Late Devonian extinction (~375-360 million years ago) -- 70% of species lost
Permian-Triassic extinction (~252 million years ago) -- 96% of marine species lost
Triassic-Jurassic extinction (~201 million years ago) -- 70-75% of species lost
Cretaceous-Paleogene extinction (~66 million years ago) -- 75% of species lost (killed the dinosaurs)
Various smaller extinction pulses throughout their history

Sharks were not untouched by these events. Many shark lineages went extinct during each crisis. But the group as a whole persisted, diversifying again after each catastrophe.

Several factors contribute to their survival:

Dietary flexibility. Sharks as a group are not specialized feeders. Different species eat everything from plankton (whale sharks, basking sharks) to fish, squid, marine mammals, crustaceans, and bottom-dwelling invertebrates. This dietary breadth means that some shark species can find food even when ecosystems collapse.

Marine habitat. Ocean environments tend to be more stable than terrestrial ones during mass extinctions. Ocean temperatures change more slowly, and marine food webs, while disrupted, rarely collapse as completely as land-based ones.

Reproductive adaptability. Sharks use a variety of reproductive strategies -- some lay eggs, others give live birth, and some even have a form of uterine cannibalism where embryos eat their siblings in the womb. This diversity of reproductive strategies increases the odds that some lineage finds conditions favorable.

Efficient physiology. Sharks have lower metabolic rates than most bony fish, meaning they need less food to survive. During resource-scarce periods following mass extinctions, this metabolic thriftiness is an advantage.

Things Younger Than Sharks

The list of things that postdate sharks in Earth's history is absurd:

Trees (by ~50 million years)
All four-legged land animals (by ~80 million years)
Insects (roughly contemporaneous or slightly younger)
All dinosaurs (by ~220 million years)
All mammals (by ~250 million years)
All flowering plants (by ~300 million years)
All birds (by ~300 million years)
All primates (by ~385 million years)
The Atlantic Ocean (by ~250 million years)
The Himalayan Mountains (by ~400 million years)
Saturn's rings (possibly -- recent evidence suggests the rings may be only 100-400 million years old)

Sharks are so ancient that they predate the concept of bones. The earliest sharks evolved before vertebrates developed bony skeletons. This is why shark skeletons are made of cartilage rather than bone -- it is not a simplification from a bony ancestor. Cartilage came first. Sharks kept it.

The octopuses in the ocean today are sharing their habitat with an organism whose lineage predates nearly every major feature of the modern world. Next time you see a shark -- on a documentary, at an aquarium, or in the water -- you are looking at a design that has been tested against every catastrophe the planet has thrown at life for 450 million years.

It is still here. That says everything.