Despite the Arctic's harsh environment, the zone contains a varied plant and animal life. Cycles of overpopulation and food scarcity characterize Arctic ecology. Humans living in the Arctic have long had a stable relationship with their environrnent, but modern technology threatens this relationship. Plants Arctic plants have evolved many specialized adaptations for life on the windswept tundra, with its low precipitation and long, severe winters. Trees and shrubs that grow there are much smaller than related forms to the south, and their tissues are far more resistant to freezing and thawing.
Arctic plants have short roots because of permafrost.
Mosses and lichens are the most common plant life, the lichens helping to break down surface rocks into soil. During the brief summer grasses and attractive flowering plants appear, sometimes completing their entire life cycle within one month. The buds of many Arctic plants grow just above or below the suface of the soil and are protected by plant parts remaining from former years. Only three species survive the winter in seed form. Because many kinds of asexual reproduction occur and self-pollination predominates, genetic variation is slight within Arctic plant species.