Tiktaalik

Tiktaalik Chicago

Tiktaalik is a genus of extinct sarcopterygian (lobe-finned) fish from the late Devonian period, with many features akin to those of tetrapods (four-legged animals). It is an important fossil in the study of the transition from fish to amphibians, showcasing how the first vertebrates may have moved from aquatic to terrestrial environments. Discovered in the Canadian Arctic in 2004 by a team led by paleontologists Neil Shubin, Edward Daeschler, and Farish Jenkins, Tiktaalik roseae is the only species within this genus known to date.

Description

Tiktaalik's body structure bridges the gap between fish and tetrapods. It had a flat, crocodile-like head with eyes on top, suggesting a lifestyle of a shallow water predator. Unlike many fish, Tiktaalik had a neck, allowing its head to move independently of its body. Its fins contained bones that resemble the upper arm, forearm, and primitive versions of wrists and fingers, indicating it could support itself in shallow water or mud. These features suggest Tiktaalik was capable of doing push-ups, a movement that would have been useful for navigating in shallow waters or even on land for short periods.

Significance

The discovery of Tiktaalik has profound implications for our understanding of the evolution of tetrapods. It fills a crucial gap in the fossil record between aquatic fish and early amphibians, providing tangible evidence of the transition from water to land. Tiktaalik's features demonstrate how tetrapods may have evolved their distinctive limb structures and how the transition from an aquatic to a terrestrial lifestyle occurred.

Habitat

Tiktaalik lived in a subtropical, freshwater environment, as evidenced by the sedimentary rocks in which its fossils were found. This environment was likely a complex ecosystem with a variety of channels, floodplains, and ponds, providing a diverse range of habitats that may have facilitated the evolutionary pressures necessary for the transition to land.

Discovery and Research

The fossils of Tiktaalik were discovered on Ellesmere Island in Nunavut, Canada. The site's remote location and the harsh conditions posed significant challenges to the research team. The discovery was the result of targeted expeditions to find fossils that would fill the gap between fish and the earliest known tetrapods. Tiktaalik's discovery was hailed as a major breakthrough in evolutionary biology, providing a snapshot of the process of evolution in action.

Impact on Evolutionary Biology

Tiktaalik has become a key exhibit in the debate on evolution, particularly in discussions about the evidence for evolution and how it occurs. Its discovery supports the theory of evolution by demonstrating a clear example of a transitional form. It also provides insights into the mechanisms of evolutionary change, such as how environmental changes can drive the development of new physical traits and behaviors.

See Also

• Evolution of tetrapods
• Devonian period
• Sarcopterygii
• Fossil record
• Paleontology