Why is a bush or tree more accurate than line to describe how hominids developed into modern humans?

You're absolutely right! Using a "bush" or "tree" is a much more accurate representation of hominid evolution than a straight "line". Here's why:

* Multiple lineages: Hominid evolution wasn't a single, linear progression. Instead, there were multiple species evolving simultaneously, some branching off into new species, others going extinct. This creates a branching, tree-like pattern.

* Interbreeding: Recent discoveries show that different hominid species interbred. This further complicates the picture, indicating that there was gene flow between different lineages, not just distinct lines of descent.

* Evolutionary mosaicism: Hominids didn't evolve all their traits at once. Instead, they developed features at different rates, leading to a "mosaic" of characteristics, some more primitive, some more advanced. This means that some traits in modern humans might be more closely related to traits in extinct species than others.

Think of it this way:

* Line: Suggests a direct progression from one species to the next, with clear cut steps.

* Bush/Tree: Shows the complexity of evolution with multiple branches, interconnections, and dead ends.

The bush or tree model emphasizes the diversity and complexity of hominid evolution, better reflecting the scientific understanding of how modern humans came to be.