This implies that internal fertilization might have evolved right alongside vertebrates—perhaps it served as the reproductive strategy of choice for the earliest examples of our most ancient ...

The female reproductive system is a complex system of external and internal organs that produce eggs that are necessary for reproduction. One egg is prepared for fertilization every month.

Thus, at some point, early fishes must have lost the internal fertilization method seen in placoderms, before some of their descendants 're-invented' organs with a similar function — ranging ...

In external fertilization, the sperm fertilize the ova directly, outside of the female's sexual organs. Several fish achieve fertilization this way. The internal fertilization is more common among ...

Fertilization mode drives sperm length evolution across the animal tree of life. Nature Ecology & Evolution , 2021; DOI: 10.1038/s41559-021-01488-y Cite This Page : ...

Until now, biologists had no idea that the switch from internal to external fertilization was evolutionarily possible. Placoderms were previously considered by some to be an evolutionary dead end ...

Fish reproduce sexually through external and internal fertilization, but there’s so much more to the reproduction process, ...