Antarctic Ecosystem

CLIMATIC HISTORY:

Millions of years ago, Antarctica was temperate, and home to many species of tropical plants and animals. Today, things are very different. The last Ice Age caused the Earth's extremities to freeze, thus creating the thick cape of ice and snow that now covers Antarctica. This triggered the birth of many polar species, some of which are long extinct, others that we know quite well. However, as we travel further and further away from the end of the Ice Age, the global climate begins to heat up, and the sea levels rise. This is also partly due to greenhouse gases being released into the atmosphere by human factories, vehicles and power plants. The Antarctic ecosystem is strongly affected by this change in climate, which we call 'Global Warming', and many polar species are now threatened or endangered to various degrees.

NATURAL ECOSYSTEM:

All antarctic species are connected to the water, for the land is too cold, dry and dark to support much life. So the entire ecosytem has adapted to live in harsh, frigid,wet conditions.

• PLANT-LIFE: due to the extreme weather conditions found in Antarctica, very few plant species can survive on the ice. These include 150 species of lichen, 30 species of moss, numerous fungi and liverwort.
• THE BASICS: the basis of every marine food chain is plankton, a minute crustaceon-like creature, which in turn, live off microscpic organisms in the water. They inhabit the freezing antarctic waters in abundance, and provide foood for another important animal species: krill. Krill, when is comes to foodchains, is pretty much second-last from the bottom. Most marine species living in the antarctic waters are sustained by krill.
• PENGUINS: The first antarctic explorers mistook penguins for fish, and it took them a while to discover that this was not so. Penguins are a family of aquatic birds, and there are 17 different penguin species living in and around Antarctica. They are the ultimate athletes when it comes to swimming, slicing through the water at speeds as high as 50kph.  Their bodies are designed for speed in water, with retractable heads, a breastbone which acts as a keel, and strong, short webbed feet. Their bodies, so graceful in water, have become awkawrd on land over centuries of evolution. Their short legs make thir walk stilted and comical, and so slow that they sometimes resort to sliding along the ice on their bellies rather than walk. Overtime, their wings evolved into more flipperlike limbs, as the birds took to the seas: nowdays, most penguns spend 75% of their time at sea, only coming on land to take care of their families and rest. All penguin species lay eggs on the land, but only four of the 17 antarctic species do so on the antarctic continent: the Emperor, the Adelie, the Chinstrap and the Gentoo. Of these four, the Emperor penguin has the most curious way of incubating the egg and young. Almost all other penguins lay around two eggs on a pile of rocks or a sandy burrow, but the Emperor penguin has only one egg/chick at the time. After the female has laid it, the male takes onto his feet and covers it with a flap of warm blubber and feathers to keep it warm. He then incubates the chick until its mother returns after months of hunting.
• SEALS: there are four native species of antarctic seal. Seals are some of the hardiest mammals on Earth; they have been found thriving in climates where even rocks have little hope of surviving. Seals are much more abundant in Antarctica than in the arctic, where they are the easy prey of polar bears, the top predators at the North Pole. Down South, seals are the baddest cats in sea. Being at the top of the food chain has practically no disadvantages, and some seals, especially elephant and leopard seals are very well suited to that position. Seals spend virtually all their time at sea, only coming on land to mate and take care of the young. Mother seals raise their pups without the help of males, though some species form colonies of mothers and young pups, to consrve heat and protect the next generation from predatory whales. Elephant seal males are twice as large as the females, and one of the fiercest animals in the South. They will fight to the death for the right to mate.  All seals are carnivores, feeding on a varied diet of fish, crustaceans, krill and squid. Like penguins, seals are clumsy and slow on land, where they are weighed down by body fat and are unable to support themselves on their short webbed fins. To move around, th slide along their bellies at a slow pace.
• WHALES: there are 8 whale species living in and around the Southern Ocean. The two top predator whales in the South are the Orca whale and the Sperm whale. These are both toothed whales, unlike the other 6 species. They hunt and catch large prey, whereas the baleen whales use their thin, bristle-like teeth to catch enormous quantities of krill in their cavernous mouths. Baleen whales are in general far larger that toothed whales. Whales are the largest mammals in the world, and the only family except for manatees that have adapted to living their whole lives at sea. Like all other mammals, they are warm-blooded, breathe air, give birth to live young, to whom they feed milk.