Hypersea: Life on Land

by Mark A.S. McMenamin

This text describes the evidence for how life moved from sea to land, beginning more than 400 million years ago, employing the concept of Hypersea which is the idea that the barren land surfaces of the Earth could only have been colonized by multicellular organisms working in concert.

Genres: Science, Ecology, History

343 pages, Paperback

First published April 15, 1994

About the author

Mark McMenamin is Professor of Geology in the Department of Earth and Environment at Mount Holyoke College in South Hadley, Massachusetts.

Reviews

[Andy Caffrey · Rating 4 out of 5]

This is a hardcore science book, not a popular science book. So you pretty much have to be facile with college level biology to make your way through it.

It's also written backwards. You get the intro to what hypersea is in the last chapter. Until that point the book is mostly about parasites and hyperparasites found in plants, lichen, algae. So that's what your head swims through in your journey into hypersea.

Also, I'm still not clear on the basics of hypersea. It seems to be that life left the oceans en masse during the Cambrian explosion a half a billion years ago as little bags of ocean, each life form a mini-aquarium containing parasites and parasites of parasites. There is a lot in the book about lichen... which is pretty fascinating as it isn't a single thing: it's two lifeforms from two different kingdoms. And maybe most lifeforms are actually multi-species entities.

I bought the book in the 1990s because the topic is supposed to be related to the Gaia Hypothesis. So I thought it would be a popular science book related to Earth as a living organism. As such, I was disappointed. But 45 years ago I studied marine biology at UCSD, and this book got me interested in reading some more hard core biology books, so that was good. The next book I'm reading is called Planet Ocean.

If you are interested in Earth history, fungi, symbiosis, parasites, and evolutionary biology and you have a science degree, you might find this book interesting. Otherwise, you'll probably find it a tough slog.

This book was published in 1994. I'm curious now how well the hypersea hypothesis has held up. With modern genome science techniques, there's a whole lot more these scientists have learned, I bet.

[Walt · Rating 4 out of 5]

A fascinating perspective on life. Hypersea suggests that life on land was made possible by a massive movement of fluid from the ocean into compartments of land organisms, a process that continues today through the activities of transpiration, mycorrhizal activity, and parasitism. This symbiosis-driven perspective seems to have a lot of potential, but looking through the literature since the 1990's, very few of the tests the authors recommend to investigate their theory have actually been researched. Parts of the book might be a bit too detailed on particular fossil plants, but I think Hypersea could be a quite fruitful path to explore.