Our Planet Earth

Open ocean, a vast biotope covering two thirds of the planet, some shallow, some as deep as the mountain ranges are high. The ocean has an immense, precariously complex food chain, varying from microscopic animals, like krill, to whales, which ironically feed mainly on the former. Most species swim or float in it, many coming up for air, while other dive in from land or air, often to feed, but also to procreate on the coast, where some species come to lay their eggs. Even the shore is covered with life, largely based on organic matter, such as corpses.

Shallow seas cover only 8% of earth's surface, but contain the richest, most varied maritime life: from plankton and coral (literally vital for the very existence of reefs) to birds and from various invertebrates to mammals like seals, dolphins and whales and from sea snakes to countless fish species. Their ecological interaction is greatly varied and complex, often with nearby land to, even with deserts.

Trees are earth's largest organisms and are also one of the planet's oldest inhabitants. Seasonal forests (unlike tropical rain-forest) the largest land habitats. A third of all trees grow in the endless taiga of the Arctic north. Northern America has forests that include California's sequoia's, the earth's largest trees. There and elsewhere, their vast production of photosynthesis and shade presides over a seasonal cycle of life and involves countless plant and animal species.