1. 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

2. 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?

3. 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?

4. 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)

5. 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.

6. 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

7. 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

8. 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)

9. 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)

10. 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)

11. Tropical Rain Forest Tropical Rain Forest – located at the equator
Warm and wet with lush plant growth
Average 25C, with 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)