Summary of Chapter 12 – “Who Is the Earth?”

by | Aug 17, 2022 | Uncategorized

The new cooperatively formed eukaryotic cells began themselves to cooperate fairly quickly. Evidence of chains of algae cells goes back almost to the beginnings of these cells themselves. The road to the next cooperative organism ends in multi-cellular creatures – a cooperation between genetically similar cells. The road passes through what is called a colony, which is a grouping of individuals on any level of life for some mutual benefit. Loose colonies include schools of fish, flocks of birds, and the first chains of algae cells that we just mentioned. Group protection, group feeding and mating are some of the benefits that might be obtained from these “wholes that are greater than the sum of their parts”.

 

Bacteria have formed sophisticated colonies practically since the origins of life. The stromatolites are bulbous, photosynthetic colonies, while bacterial slimes are often very sophisticated, multi species colonies. Corals are sophisticated colonies that coordinate their reproduction and work together to secrete the calcium carbonate structure of the form that they all share. Corals themselves create a larger colony together called the coral reef, while each coral polyp itself lives in cooperative symbiosis with a photosynthetic algae partner.

 

More integrated colonies, like those of some ants and termites, may have several forms of the same species working together: soldier, worker, and queen. They form what E. O. Wilson calls a superorganism, and can even carry out underground farming of fungi.

 

The volvox clade of algae were studied by Lynn Margulis. Alive today, this group of species is composed of the same basic algae cell. They can be found living alone, or as a duo swimming together, or in sets of 4, 16, 32 and up to 50,000 algae cells in the same organism. These groupings classify as different species, and show the road from a single cell through a colony, to multicellular creatures. The largest of them actually engages in sexual reproduction and produces baby organisms inside of itself.

 

The kingdoms of life now become separated. From the single new eukaryotic cell come the plants, the animals and the fungi.

 

The first cooperative stage of multi cellular creatures came and went about 600 million years ago. the Ediacarans had enigmatic functions, yet it is clear that they rose and fell together as an interconnected ecological entity – the next stage of the entity of life.

 

About 540 million years ago came the Cambrian “explosion”, when shells, teeth and claws were made from calcium carbonate, calcium phosphate, silica and chitin. Life seems to have undergone an “arms race” and elaborated into a wide array of different, sometimes fantastic forms. All of this predation and competition still created an interconnected entity – the first of Jack Sepkoski’s great ocean fauna, which lasted about 50 million years. Then came the Paleozoic fauna, with its crinoid “sea lilies”, horn corals and the chambered nautilus. Then the modern fauna arose which is with us today. Each stage was composed of thousands of interconnected species that rose and declined as a cooperative entity (though of course, the modern fauna, is still a part of life).