Hypersea

Rating:
Summary: The Triumph of the Fungus
Review: According to the authors, life on land is superior in species diversity (by a factor of about 10) and by biomass (by a factor of about 100) to life in the oceans, despite land being only about 30% of the surface of planet Earth. The authors show that life on land surpassed life in the sea very early, in the Paleozoic era (Carboniferous).

The reason for this superiority is the much better control on the supply of nutrients. While in the sea the algae are dependent on nutrients supplied by geological processes, land plants are capable of searching out nutrients using vast networks of roots and even vaster networks of fungal filaments. The fungal symbionts of plant roots (mycorrhizal fungi) feed on carbohydrates produced by the photosynthetic plants but, in exchange, provide the plants with essential nutrients.

"Mycorrhizal fungi are, according to Hypersea theory the most important organisms on land." This is a verbatim quote from the book, and I think is a good summary of the main thesis of the book. The authors state that 80% of all plants have obligate mycorrhizal associations and about 90% of all plants are in mycorrhizal associations (not necessarily obligate). Those famous delicacies, the truffles are the reproductive organs of the mycorrhizal fungi of hardwood forests in Europe.

The book does much more than explaining the workings of symbiotic fungi. The authors explore the evolutionary history of plants and fungi. Many fossils are described, like those found in the Rhynie chert (an early-Devonian rock formation near Aberdeen, Scotland).

The authors also discuss the theory by Pirozynsky, Malloch and Atsatt about the land plants themselves having arisen as symbioses of algae and fungi (as a kind of inside-out lichens), with the fungal genome being eventually included in the nuclei of the plant's cells. This is a fascinating theory, and possibly correct, but it is not essential to the Hypersea picture.

In summary, this is a very important semi-popular look at the workings and evolutionary history of the land plants, their fungal parasites and symbionts, and of the animals that feed on them (and their parasites and symbionts, and the parasites of the parasites, and so on, almost ad infinitum). This is a new way to look at life on land, one that has many merits.



Rating:
Summary: A must for understanding how the world works
Review: Ok, for those not up on their biology or the Gaia hypothesis, it might be difficult to get through, but Hypersea is well written and fascinating for those interested in knowing how life has and will continue to evolve in more complex ways. An extremely important addition to the Gaia hypothesis. You will never see the world in the same way again.

The Hypersea and Gaia hypotheses are the only two clearly defined scientific theories that have been put forth to give us some answers to questions not asked by most of biology.

Rating:
Summary: Challenges of living on land
Review: This book shows how complex lifeforms came onto the land from the sea. Hypersea does not include bacteria already living on the land, but is defined by the authors as the sum total of plant, animal, protoctistan and fungal terrestrial-based life. The challenges of living on land are discussed in detail - the need to retain water within, the difficulty extracting crucial nutrients, locomotion out of the water, etc. The importance of the fungi in extracting and delivering nutrients to plants, in return for carbohydrates produced by the plants, is considered, and a picture of the interconnectedness of terrestrial lifeforms emerges.