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The energy gained from that level decreases to about 10% of the previous level.Trophic pyramid, the basic structure of interaction in all biological communities characterized by the manner in which food energy is passed from one trophic level to the next along the food chain. The base of the pyramid is composed of species called autotrophs, the primary producers of the ecosystem. All other organisms in the ecosystem are consumers called heterotrophs, which either directly or indirectly depend on the primary producers for food energy.Within all biological communities, energy at each trophic level is lost in the form of heat (as much as 80 to 90 percent), as organisms expend energy for metabolic processes such as staying warm and digesting food ( see biosphere: The organism and the environment: Resources of the biosphere: The flow of energy). The higher the organism is on the trophic pyramid, the lower the amount of available energy. For example, plants and other autotrophs (primary producers) convert only a fraction of the enormous amount of solar energy they have access to into food energy. Herbivores and detritivores (primary consumers) take in less available energy because they are limited by the biomass of the plants they devour. It follows that the carnivores (secondary consumers) that feed on herbivores and detritivores and those that eat other carnivores (tertiary consumers) have the ;lowest
BIOMES: Taiga: The angle of incidence for incoming solar radiation is low and night is very long. Seasons are divided into short, moist, and moderately warm summers and long, cold, dry winters.temperature - vary greatly from summer to winter (-65 to + degrees Fahrenheit) Variable precipitation: 6-40 in (15-100 cm). Fire: a major factor in maintaining the biome Soil is very thin, soggy, lots of permafrost. Trees mostly conifers. Muskeg is a characteristic of the taiga, which forms when a pool of water fills with plant litter. Because the water is very low in oxygen and cold temperatures, slow decomposition peat is formed. The peat is highly
acidic and low in nutrients, The largest threat to taiga conservation is logging Flora: The dominant flora of the taiga is the White Spruce Tree. Deciduous trees found in taiga: birch, alder, aspen, larch
Flora: White Spruce, Balsam Fir, Black Spruce, Jack Pine, Tamarack, Red Spruce, Larch Forests, Douglas Fir, Scotch Pine, Clematis, Shrubs: Alders, wild roses, junipers, raspberries, and honeysuckle, Herbaceous plants: Twinflowers, Starflowers, May lilies, common wood sorrel. Tundra: Coldest biome, two types of tundra, Arctic and Alpine,too cold for trees only shrubs, sedges, grasses, mosses, and lichen.
Tundra→Temperature:most of the year below freezing. Precipitation: 150-250 millimeters per year, Wind:48-97 km/h Plant Adaptations: chamaephytes (low to the ground),Perennials (live more than two years) with buds that remain in hibernation. Difference between Arctic and Alpine: Much more arctic tundra.Alpine tundra only exists on mountains, soil is dry, lower oxygen concentration Arctic tundra has wet soil,
Taiga vs tundra: Tundra much colder, no trees, different species, tundra more barren taiga more landforms
Deciduous Forests: Two types Temperate and Tropical/SubtropicalContain deciduous trees(drop their leaves), trees have less energy because of weak sunlight→less Photosynthesis, Climate: -30° C to 30° C. Average is 50°F,Precipitation:75-150cm, Ecologic Importance: Reduce erosion, provide resources for animals, maintain biodiversity, regulate local climate, produce oxygen, stabilize weather patterns, reduce greenhouse gas effects, water and air filter. Boreal Forest: southern part of the taiga; the part where conditions are suitable for trees to grow. Zero population growth designates a near balance of births and deaths
Type I, II, III Type I: high survivorship Type II:constant proportional individual deaths Type III:low survivorship (high death rate at young age)
Population growth(G = rN) where G = population growth per unit time, r = rate of increase, N= the number of individuals.
A general formula for calculating the population growth rate is Gr = N / t. Gr is the growth rate measured
in individuals, N is the change in population, and t is the period of time.
Primary : The ecological succession of vegetation that occurs in passing from barren earth or water
to a climax community
● Secondary : The development of biotic communities in an area where the natural
vegetation has been removed or destroyed but where soil is present
● Tertiary Succession: Tertiary succession is the process of recolonizing an area that has
been completely abandoned by plants and animals. Tertiary succession is very rare,
because it usually occurs only in areas that have been completely destroyed by a natural
event, such as a volcanic eruption or a hurricane.
