Short-spined sea urchin fossilswere found directly above long spined sea urchin fossils in a layer of rock. What do the differences between the two sets of sea urchin fossils suggest about them?

Question

Lexie Stanton

Biology

28 September, 19:45

Short-spined sea urchin fossilswere found directly above long spined sea urchin fossils in a layer of rock. What do the differences between the two sets of sea urchin fossils suggest about them?

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Answers (2)

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Alayna Armstrong · Answer 1

It suggests that the longer spined sea urchins existed before the shorter spined sea urchins.

PbJ · Answer 2

As the animals die, they get covered in layers. The lowest being the oldest. The difference is showing us a direct link between the two fossils. This means that the longer-spined sea urchins existed before the shorter-spined sea urchins. And evolved to have shorter spines rather than long ones.