Where did the first vertebrates evolve?

• A. In the ocean
• B. In the atmosphere
• C. In freshwater lakes
• D. On land

Answer: (A)

Verified step by step guidance

1. Understand the definition of vertebrates: Vertebrates are animals with a backbone or spinal column, which is a key characteristic of this group.
2. Consider the evolutionary timeline: The first vertebrates are believed to have evolved during the Cambrian period, which is part of the Paleozoic Era.
3. Examine the environmental conditions of the Cambrian period: During this time, the Earth's environment was predominantly aquatic, with vast oceans covering much of the planet.
4. Identify the habitat of early vertebrates: The earliest vertebrates were jawless fish-like creatures, which indicates that they were adapted to living in water.
5. Conclude the most likely environment for the evolution of the first vertebrates: Given the aquatic nature of early vertebrates and the conditions of the Cambrian period, it is most plausible that the first vertebrates evolved in the ocean.