Age of Fishes

Definition

The Age of Fishes refers to the Devonian period, a time spanning from about 419 to 359 million years ago, when fish flourished and diversified in marine environments. This era saw the emergence of various fish groups, including early jawed fishes and lobe-finned fishes, which played a crucial role in the evolution of vertebrates. It marked significant advancements in fish anatomy and ecology, setting the stage for future vertebrate life on land.

5 Must Know Facts For Your Next Test

1. The Devonian period is often called the Age of Fishes because it was during this time that fish diversity reached unprecedented levels, leading to various adaptations.
2. Key innovations included the development of jaws, which allowed fish to become more effective predators.
3. Famous groups like placoderms dominated early ecosystems, showcasing complex behaviors and ecological roles.
4. Lobe-finned fishes, significant in this period, eventually led to the evolution of tetrapods, marking the transition from water to land.
5. The end of the Devonian period experienced significant extinction events that impacted fish diversity and paved the way for new evolutionary paths.

Review Questions

• What were some key evolutionary advancements in fish during the Age of Fishes?
  • During the Age of Fishes, notable evolutionary advancements included the development of jaws and paired fins. Jaws allowed fish to expand their dietary options and become more effective predators. The emergence of lobe-finned fishes is particularly significant as they possessed fleshy fins that would later evolve into limbs for terrestrial animals. These advancements not only shaped aquatic ecosystems but also laid the groundwork for vertebrate evolution.
• Analyze the impact of placoderms on marine ecosystems during the Devonian period.
  • Placoderms played a pivotal role in marine ecosystems during the Devonian period by establishing themselves as dominant predators. Their armored bodies and advanced jaw structures allowed them to adapt to various ecological niches. As they thrived in diverse habitats, placoderms influenced food webs and competitive dynamics within aquatic environments. This predatory dominance set a precedent for later vertebrate evolution and ecological interactions.
• Evaluate how extinction events at the end of the Devonian period reshaped fish diversity and what this meant for future vertebrate evolution.
  • Extinction events at the end of the Devonian period had profound effects on fish diversity, leading to significant declines in certain groups like placoderms while allowing others such as lobe-finned fishes to survive and diversify. This shift ultimately facilitated a transition towards tetrapods, as surviving lobe-finned species began adapting to terrestrial environments. The reduced competition and altered ecological landscapes created by these extinction events set a new course for vertebrate evolution, allowing for greater diversification on land.

Related terms

Placoderms: An extinct class of armored prehistoric fish that were among the earliest jawed vertebrates, thriving during the Devonian.

Lobe-finned Fishes: A group of fishes with paired fins that are fleshy and lobed, which eventually gave rise to the first land vertebrates.

Devonian Extinction: A series of extinction events during the late Devonian that significantly affected marine life, including fish populations.