1932

Abstract

The placenta is a complex organ that mediates all physiological and endocrine interactions between mother and developing embryos. Placentas have evolved throughout the animal kingdom, but little is known about how or why the placenta evolved. We review hypotheses about the evolution of placentation and examine empirical evidence in support for these hypotheses by drawing on insights from the fish family Poeciliidae. The placenta evolved multiple times within this family, and there is a remarkable diversity in its form and function among closely related species, thus providing us with ideal material for studying its evolution. Current hypotheses fall into two categories: adaptive hypotheses, which propose that the placenta evolved as an adaptation to environmental pressures, and conflict hypotheses, which posit that the placenta evolved as a result of antagonistic coevolution. These hypotheses are not mutually exclusive. Each may have played a role at different stages of the evolutionary process.

Loading

Article metrics loading...

/content/journals/10.1146/annurev.ecolsys.110308.120209
2009-12-01
2024-03-28
Loading full text...

Full text loading...

/content/journals/10.1146/annurev.ecolsys.110308.120209
Loading
/content/journals/10.1146/annurev.ecolsys.110308.120209
Loading

Data & Media loading...

  • Article Type: Review Article
This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error