You and your friend inspect a group of fossils from different organisms with various features. Your friend is convinced that all of the fossils are unrelated, but you find evidence that these organisms share an ancestor. What is an example of evidence that you can use to best support this argument? Number of bones, heights, patterns in limb structure or tooth features?
To support the argument that these fossils share a common ancestor, patterns in limb structure would be the most relevant evidence to consider.
The number of bones or heights cannot be relied upon solely because different organisms can have variations in these features without necessarily sharing a common ancestor. For example, mammals have different bone structures and heights, but they share a common ancestor with other vertebrates.
Tooth features can also provide evidence, but they may be subject to convergent evolution. This means that unrelated organisms can develop similar tooth features due to similar ecological niches or dietary adaptations. Thus, tooth features alone may not convincingly demonstrate a shared ancestor.
On the other hand, patterns in limb structure can provide a strong indication of a shared evolutionary history. These patterns reflect the underlying genetic blueprint that guides the development of limbs. Similar limb structures among different organisms can suggest a common ancestor that possessed that specific arrangement. For instance, if the fossils display similar patterns in limb structure, such as the presence and arrangement of bones or the overall architecture of the limb, it would strongly suggest a shared ancestor. This similarity would be less likely to arise independently through convergent evolution.
Therefore, among the given options, patterns in limb structure would be the most compelling evidence to support the argument that these fossils share a common ancestor.