External fertilization, however, seems to be a more recent development in sexual strategies than the more intimate alternative—internal fertilization. According to research published yesterday ...

“Biologists thought that there could not be a reversion back from internal fertilization to external fertilization, but we have shown it must have happened this way.” Go back far enough in ...

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 ...

"In species with internal fertilization -- like mammals, birds and insects -- sperm fertilize eggs inside the female's body, while in species with external fertilization -- like sea urchins and ...

Spermcasting is like a combination of internal and external fertilization; for example, a river mussel might eject sperm into a stream, and that sperm would ride the currents until it is picked up ...

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.

They reproduce sexually through external fertilization (releasing eggs and sperm into the water) and internal fertilization ...

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 ...