Planet Earth Urdu - From Pole to Pole
Overview
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"Planet Earth" travels around the Earth, finding where the sun always shines and where it's rarely seen. Next, they find where water is abundant and where it's scarce.
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Planet Earth Urdu - The Shallow Seas
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.
Planet Earth Urdu - Oceans Deep
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.
Planet Earth Urdu - Ice Worlds
The polar caps have the most extreme seasonal contrasts, growing and melting vast ice masses, so wildlife adapts by annual migrations. The majority of Antartica is a vast barren permafrost. Only 3% of the coast and peninsular peaks are where life migrates to in the spring, for a short fertile summer, attracted by rich supplies of krill and fish. Only the Emperor penguin males breed 4 months in winter 100 miles inland. The Arctic has a more complete fauna which migrates back North from the continent.