Relationships within the Tundra
The Polar Bear is the king of the arctic tundra biome

Examples of Predator and Prey relationships in the Arctic Tundra Food Web

Wolves and Caribou
Wolves and Caribou both live in the arctic tundra. The Wolf is the predator. He hunts the Caribou and eats it for energy. The Caribou eats plant life to obtain energy.
Polar Bears and Arctic Foxes
The Polar Bear eats the Arctic Fox for energy. The Arctic Fox eats other small rodents to obtain energy.
Herbivore Plant relationships
There are approximately 1700 plants in the tundra. They include some flowering plants, low shrubs, sedges, grasses, and liverworts. Lichens, mosses, and algae are also common. In general, tundra plants are low growing, have shallow root systems, and are capable of carrying out photosynthesis at low temperatures and with low light intensities.
Some Arctic herbivorous mammals include
  • Lemmings
  • Voles
  • Caribou
  • Arctic hares
  • Squirrels
    These mammals eat all the plants listed above.
The Lemming is at the bottom of the food chain
Caribou/Reindeer, the primary food source for the Polar Bear

The Primary consumers eat the Producers in a Herbivory Plant relationship. The Secondary consumers eat the Primary consumers in a Predator Prey ralationship. This is the Arctic Food Chain
Keystone Species - a species whose presence and role within an ecosystem has a disproportionate effect on other organisms within the system. A keystone species is often a dominant predator whose removal allows a prey population to explode and often decreases overall diversity. Other kinds of keystone species are those, such as coral or beavers, that significantly alter the habitat around them and thus affect large numbers of other organisms.

The Keystone Species in the Arctic are
Primary Consumers
  • American Pikas
  • Musk Oxen
  • Caribou
  • Lemmings- most likely to be consumed by the Secondary Consumers
  • Arctic Hares
Secondary Consumers
  • Arctic Foxes
  • Brown Bears
  • Arctic Wolves
  • Snowy Owls
  • Polar Bears

American Pikas
Musk Ox
Arctic Fox

Why The Polar Bear is a Keystone Species?
The Polar Bear is important to maintain balance in the ecosystem. It is being affected in a bad way since a warmer climate is now causing Polar Bears to swim longer distances to hunt. For example,if a keystone species like the polar bear is removed from the Arctic habitat, seal populations will rise significantly, which also affects other organisms in the food chain such as the small fish and plankton. The small fish and plankton population will decrease drastically since more seals need to be feed. A food web is controlled by it's keystone species and will fall apart like a castle that is built with out walls or a moat.
Symbiosis including Mutualism, Parasitism, and Commensalism
Symbiosis- the living together of two dissimilar organisms,as in mutualism,commensalism,and parasitism
Mutualism- a relationship between two species of organisms in which both benefit from the association
Parasitism- a relation between organisms in which one lives as a parasite on another
Commensalism- (of an animal, plant, fungus, etc.) living with, on, or in another, without injury to either
The most well known mutualistic relationships are lichens. Lichens are found throughout the arctic tundra, where they provide food for the reindeer in the winter.They are the first plants to grow on bare rock and they are able to survive the hot sun in exposed areas.
The lichen is made up of two organisms; a fungus and an alga. The algal cells live inside the hyphae of the fungus. The algal cells photosynthesize and give sugars and oxygen to the fungus. In return the fungus provides protection, water and salts for the small algal cells. Also, the fungus is able to grow on bare rock and other areas where other plants cannot. This is because the fungus is able to take a firm hold where most plant roots are unable to penetrate.

An example of parsitism in the tundra is a tape worm in the body of the caribou. The tapeworm takes in the nutrients from the caribou. Soon the caribou dies and the tape worm gets its food.Why is the tapeworm a parasite? It lives in a close relationship with another organism, its host, and causes it harm. The parasite is dependent on its host for its life functions. The parasite has to be in its host to live, grow, and multiply. Parasites rarely kill their hosts. Tapeworms attach themselves in the lining of the small intestine, and cause diseases, and malnutrition as well, as they eat the nutrients and keep them from going to the host. It lives in the intestines of the predator, or final host.
The tapeworm can be very long or hardly visible depending on the parasite. When visible it looks like a long flat measuring tape. It has a head (or scolex) which
attaches onto the wall of the intestine by way of a ring of hooks and suckers. This allows the parasite to live off the food in the animal’s gut.

In commensalism, the barren ground caribou and the arctic fox have a commensalistic relationship. The fox follows the caribou who removes the snow covering to get at lichens under the soil. The fox then hunts the subnivean mammals that have been unearthed by the caribou. The fox is the thief in the joker and the thief situation we got going on here. Neither is harmed but both benefit here indirectly. The Fox below is digging where a caribou was once walking.

Presented my Matt Mamros