Characteristics of Ecosystems

Succession Succession—plant regrowth after a catastrophe Primary and secondary Primary—development in an area previously uninhabited First animals in the area are called pioneer species Exposed rock Lichen are the first plant to grow

Primary Succession Begins where there is no soil Sides of volcanoes Landslides flooding Lichens, who need no soil, grow on rocks Then mosses grow on new soil Pioneer species Simple plants die, creating more nutrients for soil Grass, wildflowers and other plants take over

Secondary Succession Reestablishment of a damaged ecosystem where soil was left intact No end, any damages causes it to go over and over again

Secondary Succession Begins where soil is already present and organisms once lived Occurs faster than primary Forest fires, tornadoes

Climax Community Stable group of plants and animals that is the end result of succession process Does not always mean big trees Grasses in prairies Cacti in deserts

Energy Flow Begins with the sun as photosynthesis It flows through ecosystems from producers to consumers. Producers make food Consumers use food by eating producers or other consumers

Autotrophs Any organism that can produce its own food supply A.k.a. producer Plants, algae, some protists and bacteria Can also be: Photoautotrophs Using light energy Chemoautotrophs Using chemical energy from hydrothermal vents on the ocean floor or gets it from inside the guts of other animals

Tube Worms living in Black Smoker copyright cmassengale

Feeding Relationships

Food Chains Energy flows through an ecosystem in one direction from producers to various levels of consumers

Feeding Relationships Food Chain Simple energy path through an ecosystem Food Web More realistic path through an ecosystem made of many food chains

Food Chain

Food Web

Trophic Levels Each level in a food chain or web is called a trophic level Producers Always the first level How the energy enters Herbivores second trophic level Primary consumers Carnivores/Omnivores Remaining trophic levels Secondary and tertiary consumers

Ecological Pyramids Graphic representation of the relative amounts of energy or matter at each trophic level Energy pyramid Biomass pyramid Pyramid of numbers

Energy Pyramid

Biomass The amount of organic matter comprising a group of organisms in a habitat As you move up a food chain, both available energy and biomass decrease Energy transfers up, but diminishes with each transfer

Biomass Pyramid

Pyramid of Numbers