Adaptations that enable plants to obtain sunlight are common. Trees here are among the world’s tallest.Biotic Factors – Animal LifeCamouflage helps insects and ground-dwelling mammals avoid predation. .Many animals are browsers—they eat a varied diet—an advantage in an environmentwhere vegetation changes seasonally.Boreal ForestDense forests of coniferous evergreens along the northern edge of the temperate zone are called boreal forests, or taiga.Winters are bitterly cold, but summers are mild and long enough to allow the ground to thaw.Boreal forests occur mostly in the northern part of the Northern Hemisphere. The word boreal comes from the Greek word for “north.”Abiotic FactorsBoreal forests have long cold winters and short mild summers.There is moderate precipitation and high humidity.The soil is acidic and nutrient-poor.Biotic Factors – Plant LifeThe conical shape of conifers sheds snow, and their wax-covered needlelike leaves prevent excess water loss, making conifers well suited to the boreal forest environment.In addition, the dark green color of most conifers absorbs heat energy.Biotic Factors – Animal LifeStaying warm is the major challenge for boreal forest animals.Most have small extremities and extra insulation in the form of fat or downy feathers.Some migrate to warmer areas in winter.TundraThe tundra is characterized by permafrost,a layer of permanently frozen subsoil.During the short cool summer, the ground thaws to a depth of a few centimeters and becomes soggy. In winter, the top layer of soil freezes again. The cycle of thawing and freezing, which rips and crushes plant roots, is one reason that tundra plants are small and stunted.Cold temperatures, high winds, a short growing season, and humus-poor soils also limit plant height.
Abiotic FactorsThe tundra experiences strong winds and low precipitation.The summers are short and soggy, and the winters are long, cold, and dark. The soil is poorly developed, with a permanently frozen subsoil layer called permafrost.Biotic Factors – Plant LifeBy hugging the ground, mosses and other low-growing plants avoid damage from frequent strong winds.Seed dispersal by wind is common. Many plants have adapted to growth in poor soil, like legumes, which have symbiotic bacteria on their roots that fix nitrogen.Biotic Factors – Animal Life