Antarctic Animals

Antarctica

Antarctica is the most coldest continent on Earth. It's a barren land of snow. The Earth's axis is tilted at an angle of 23.5 degrees. That's why Antarctica has two seasons: Summer and Winter. 

Because of the tilt in the Earth's axis, when Antarctica faces completely away from the Sun, it's Winter. The winter is extremely cold because the continent faces completely away from the Sun. That part of the year, there is no sunlight. That means no plants. 

But summer is completely different. When Antarctica completely faces towards the sun, the ice bergs and glaciers melt away. In the waters of the Antarctic Ocean, there is microscopic marine algae called Phytoplankton. it is also known as microalgae. When the ice which covers the water melts away, the sunlight reaches the Phytoplankton and helps it to carry out photosynthesis(the process of plants making their own food). There are small crustaceans(animals without backbone) called Krill. These animals eat the Phytoplankton. Then, Antarctic fish, like the Antarctic Cod, eat the Krill. Then the cod gets eaten by Penguins, then the Penguins are eaten by Orcas(Killer Whales). This is a food chain.

The Phytoplankton is the Producer,

The Krill is the Primary Consumer,

The Cod is the Secondary Consumer,

The Penguin is the Tertiary Consumer,

And the Orca is the APEX PREDATOR.

A collection of food chains is called a food web.

Blue whales can't eat anything but krill because the whale's oesophagus(food pipe) is too narrow, the bigger creatures can't go through, so these blue whales eat about 4 tonnes(tons) of krill everyday. 

The Blue Whales eat more krill in one bite by lunge feeding. They lunge through large swarms of krill with their mouths open. 

In the picture, the blue whale is lunging through the swarm of krill. The baleen is the small thick hair structures that help the whale to separate krill from seawater. 

Krill

Krill are the small crustaceans that live underwater. They look little and might seem like needless creatures, but without them, the whole Antarctic food web would be broken. If you look at the food chain, and make a tiny change by removing the Krill, then you will find that there is no way for the other creatures like cod, penguin and orca to survive. 

Also, Krill are the only type of creature that Blue Whales can eat, so if no krill, then no blue whale.

That's the reason why Krill is also known as Keystone Species.

Picture credits: Wikipedia and Google