Succession Succession – the orderly natural changes and species replacements that take place in the communities of an ecosystem Takes a long time, not easily observable Occurs in stages

Primary Succession From a disturbance, such as rocks moving to expose new soil starts Primary succession. Pioneer species set up such as mosses and lichens As these species die, they create soil for further species Shrubs, ferns, grasses come next Pines, beeches and maples colonize after that When the community stabilizes, a climax community is established How can you tell?

Secondary Succession Occurs when interrupted by natural disasters or human actions Occurs in areas that previously contained life and soil. Pioneer species maybe different since the soil is already present Occurs by the same process as primary succession. Takes less time Why?

Biomes Ecosystems that have similar kinds of climax communities are called Biomes. Biomes are limited by temperature and precipitation (terrestrial types) There are two major types of biomes Aquatic (those in the water, sea) (3/4 of the Earth) Terrestrial (those on land)

Marine Biomes Estuary – coastal body of water, in part surrounded by land where freshwater and saltwater mix. Scientists separate marine biomes into two parts: Photic Zone : portion of the biome shallow enough to allow light through Plankton, juvenile marine organisms Aphotic zone : deeper water where light cannot penetrate Adapted to life in the dark.

Terrestrial Biomes - Tundra Tundra – Circles the poles, treeless with long summer days and short periods of winter sunlight Under the topsoil is a frozen part called permafrost. Soil is nutrient poor and can’t hold larger plants & trees Small mammals live there like owls and lemmings

Taiga Taiga – just south of the tundra Warmer than the Tundra, land of fir & spruce trees Canada, Northern Europe & Asia Contains larger species like Caribou, snowshoe hare

Desert Desert – driest biome with sparse plant life Less than 25 cm of precipitation Organisms have adapted to conserve water (mice, scorpions, snakes, owls, etc)

Grassland Grasslands – covered by grasses and similarly small plants 25 – 75 cm of precipitation Occupies more area than any other land biome Good for growing crops Dominated by grazing animals (bison)

Temperate Forest Temperate Forest – above and below the equator Nutrient rich soil with Hardwood trees 70 to 150 cm of precipitation Home to many forest animals (bears, squirrels, salamanders)

Tropical Rain Forest Tropical Rain Forest – located at the equator Warm and wet with lush plant growth Average 25C, with 200-600 cm of rain Home to the most amount of species on the planet Has many niches due to the layers of the rainforest (forest floor, trees, canopy, etc)