Final answer:
The term 'living fossil' is misleading because it ignores the fact that all organisms, including those known as living fossils, have evolved over time, despite retaining some ancestral traits. It also emphasizes the importance of not solely relying on physical appearances for determining evolutionary relationships, as they can sometimes lead to incorrect conclusions.
Step-by-step explanation:
The term "living fossil" often applied to creatures like horseshoe crabs is misleading because it suggests that these animals have remained unchanged from their earliest ancestors found in the fossil record. However, this is not accurate, as all living organisms, including those referred to as living fossils, undergo some degree of evolution and adaptation to changing environments over time. The horseshoe crab has indeed maintained some primitive features, but it has also evolved new traits that are not present in ancient fossils.
It's important to recognize that appearances can be deceiving in understanding evolutionary history. For instance, similarities in physical features—like the cone-shaped shells of limpets and barnacles—might lead someone to assume a close relationship, but in reality, barnacles are more closely related to crabs. This exemplifies the importance of using multiple lines of evidence to determine phylogenetic relationships.