Ecozones
Ecozone. Ecosystem. Ecosphere. What’s the difference between all these “ecowords”? It’s all relative, starting with an ecosystem, which is a natural community that can exist anywhere on earth. Combining the word eco, which means habitat, and system, which refers to the interdependent way natural elements fit together, an ecosystem can be as big as the planet or as small as the palm of your hand. An ecozone is a relatively large ecosystem. And the ecosphere is the largest of them all.
Most Canadians—about 77%—live in cities. Buildings, roads, utility lines, vehicles, and other people surround us. Apart from some parks and other urban green spaces, the "environment" is something that for the most part exists elsewhere, at some distance from the urban core. Seen from space, however, Canada shows no roads, no political boundaries, no languages, no politics, and no people. The country’s appearance is strikingly different from this distant perspective. It is surrounded by three massive oceans, contains a large share of the world’s fresh water, and has 25% of the world’s major wetlands. Vast stretches of land are occupied by the arctic barrens, the great plains, the forests, and the western mountains. Ocean currents swirl around the margins of the continent and weather patterns move over the land and ocean masses. Virtually hidden from this distant view are tens of thousands of species of plants and animals as well as more than 30 million human beings.
The Atlantic Cod (Gadus morhua) is a medium to large saltwater fish: generally averaging two to three kilograms in weight and about 65 to 100 centimetres in length, the largest cod on record weighed about 100 kg and was more than 180 cm long! Individuals living closer to shore tend to be smaller than their offshore relatives, but male and female cod are not different in size, wherever they live.
The North Atlantic Right Whale (Eubalæna glacialis) is one of the rarest of the large whales. It can weigh up to 63,500 kilograms and measure up to 16 metres. That’s the length of a transport truck and twice the weight! Females tend to be a bit larger than males – measuring, on average, one metre longer. Considering its weight, it’s fairly short, giving it a stocky, rotund appearance. Its head makes up about a fourth of its body length, and its mouth is characterized by its arched, or highly curved, jaw. The Right Whale’s head is partially covered in what is called callosities (black or grey raised patches of roughened skin) on its upper and lower jaws, and around its eyes and blowhole. These callosities can appear white or cream as small cyamid crustaceans, called “whale lice”, attach themselves to them. Its skin is otherwise smooth and black, but some individuals have white patches on their bellies and chin. Under the whale’s skin, a blubber layer of sometimes more than 30 centimetres thick helps it to stay warm in the cold water and store energy. It has large, triangular flippers, or pectoral fins. Its tail, also called flukes or caudal fins, is broad (six m wide from tip to tip!), smooth and black. That’s almost the same size as the Blue Whale’s tail, even though Right Whales are just over half their size. Unlike most other large whales, it has no dorsal fin.
Adult Trumpeter Swans Cygnus buccinator are large birds with white feathers and black legs and feet. The feathers of the head and the upper part of the neck often become stained orange as a result of feeding in areas rich in iron salts. The lack of colour anywhere on the swans’ bodies distinguishes them from other white species of waterfowl, such as snow geese, which have black wing tips.