Tiktaalik

Definition

Tiktaalik is an extinct genus of lobe-finned fish that lived around 375 million years ago during the Devonian period. It is significant as a transitional fossil, showcasing features that illustrate the evolutionary shift from aquatic to terrestrial vertebrates, marking a crucial step in the evolution of land animals.

5 Must Know Facts For Your Next Test

1. Tiktaalik had both fish-like features, such as gills and scales, and tetrapod-like traits, including a neck and robust fins capable of supporting its weight on land.
2. The discovery of Tiktaalik in the Canadian Arctic in 2004 provided critical evidence for understanding how vertebrates transitioned from water to land.
3. It is often described as a 'fishapod' because it exhibits characteristics of both fish and early land-dwelling vertebrates.
4. The skeleton of Tiktaalik shows a flattened body, which suggests it may have been adapted for living in shallow waters and navigating on land.
5. Tiktaalik's limb structure has been studied extensively to understand the evolutionary changes that occurred during the transition from aquatic to terrestrial life.

Review Questions

• What are some of the key physical features of Tiktaalik that illustrate its role as a transitional fossil between fish and tetrapods?
  • Tiktaalik showcases several key physical features that highlight its transitional status. It possesses gills and scales typical of fish, but it also has a neck, allowing for head movement independent from the body. Additionally, its robust fins display skeletal structures resembling the limbs of tetrapods, suggesting adaptations for supporting its body on land. These characteristics provide insight into the evolutionary journey from water-based life to life on land.
• Discuss how the discovery of Tiktaalik has contributed to our understanding of vertebrate evolution during the Devonian period.
  • The discovery of Tiktaalik has significantly enhanced our understanding of vertebrate evolution by providing clear evidence of the transition from aquatic to terrestrial environments. This genus represents a pivotal moment in evolution, where adaptations such as limb structure and increased mobility on land emerged. By studying Tiktaalik's anatomy, scientists have been able to piece together how early vertebrates navigated their environments and evolved into the first tetrapods, illuminating a critical phase in the history of life on Earth.
• Evaluate the implications of Tiktaalik's features for our understanding of evolutionary biology and the process of natural selection.
  • Evaluating Tiktaalik's features reveals significant implications for evolutionary biology and natural selection. Its unique adaptations illustrate how organisms can evolve traits beneficial for survival in changing environments. The combination of aquatic and terrestrial characteristics in Tiktaalik serves as a clear example of how incremental changes accumulate over time through natural selection. By demonstrating a successful adaptation to life both in water and on land, Tiktaalik reinforces the idea that evolution is a gradual process shaped by environmental pressures and opportunities, highlighting the complex pathways through which species develop.

Related terms

Lobed-finned fish: A group of fish characterized by paired fins that are fleshy and supported by bone structures, which are believed to be ancestral to the first land vertebrates.

Tetrapods: Four-limbed vertebrates that include amphibians, reptiles, birds, and mammals, which evolved from lobe-finned fish like Tiktaalik.

Devonian period: A period in the Paleozoic era, approximately 419 to 359 million years ago, known as the 'Age of Fishes' due to the diversity and dominance of fish species during this time.