What can we infer from the stickleback fossil record about evolutionary processes occurring today?

What can we infer from the stickleback fossil record about evolutionary processes occurring today?

• A. Fossil patterns are completely different from modern evolution.
• B. Evolutionary patterns in the fossil record are consistent with processes occurring today.
• C. Fossils show no information about current evolution.
• D. Fossils prove that evolution only occurred in the past.

Answer: (B)

The stickleback fossil record shows that the same evolutionary forces shaping today’s populations were at work in the past. Marine ancestors repeatedly gave rise to freshwater forms, and the same kinds of traits—like changes in armor plates and pelvic structures—appeared in both ancient fossils and modern sticklebacks due to natural selection acting on existing genetic variation. This parallel and recurrent pattern demonstrates that the processes driving current evolution are the same processes that have operated over time, so fossil evidence is consistent with ongoing evolution today. It’s not that evolution happened only in the past or that fossils reveal nothing about today; rather, they document how evolution has repeatedly unfolded under similar forces.

The stickleback fossil record shows that the same evolutionary forces shaping today’s populations were at work in the past. Marine ancestors repeatedly gave rise to freshwater forms, and the same kinds of traits—like changes in armor plates and pelvic structures—appeared in both ancient fossils and modern sticklebacks due to natural selection acting on existing genetic variation. This parallel and recurrent pattern demonstrates that the processes driving current evolution are the same processes that have operated over time, so fossil evidence is consistent with ongoing evolution today. It’s not that evolution happened only in the past or that fossils reveal nothing about today; rather, they document how evolution has repeatedly unfolded under similar forces.