Why are females larger than males in certain species?

Question

Why are females more powerful and larger than males in certain species while in others they are smaller and weaker?

In: Biology

Answer 1

Because evolutionary biology found reasons that males evolving to be smaller and/or females evolving to be larger, suited that species’ specific biological needs.

For example, in many species, the males’ ONLY social/biological role is to fertilize the eggs of the female. In some species, their biological role is to fertilize the eggs and then be EATEN to provide nutrition to sustain the female through laying/guarding eggs, etc. It is what it is.

In order to determine why any specific species evolved the way that it did, you’d need to pick a specific one, and then analyze that species for what biological advantages come from the size of the males and females within that species.