Limiting Factor • Anything that restricts the number of individuals in a population. • Includes living and nonliving features of the ecosystem
Ecologic Pyramids Ecological pyramid - a graph representing trophic level numbers within an ecosystem. The primary producer level is at the base of the pyramid with the consumer levels above. • Numbers pyramid - compares the number of individuals in each trophic level. • Biomass pyramid - compares the total dry weight of the organisms in each trophic level. • Energy pyramid - compares the total amount of energy available in each trophic level. This energy is usually measured in kilocalories.
Energy Pyramid • Only part of the energy stored in one level can be passed to the next- most energy is consumed for life processes (respiration, movement, etc., and heat is given off) • Only 10% of the energy available within one trophic level is transferred to organisms in the next trophic level
Biomass Pyramid • Biomass- the total amount of living tissue within a given trophic level. • A biomass pyramid represents the amount of potential food available for each trophic level in an ecosystem.
Succession • Natural, gradual changes in the types of species that live in an area; can be primary or secondary. • Primary – begins in a place without soil • Secondary – where soil already exists The gradual replacement of one plant community by another through natural processes over time
Primary Succession • Begins in a place without any soil • Sides of volcanoes • Landslides • Flooding • Starts with the arrival of living things such as lichens that do not need soil to survive • Called PIONEER SPECIES
Primary Succession • Soil starts to form as lichens and the forces of weather and erosion help break down rocks into smaller pieces • When lichens die, they decompose, adding small amounts of organic matter to the rock to make soil
Pioneer species • A group of organisms, such as lichens, found in the primary stage of succession and that begin an area's soil-building process
Primary Succession • Simple plants like mosses and ferns can grow in the new soil http://www.uncw.edu http://uisstc.georgetown.edu
Primary Succession • The simple plants die, adding more organic material • The soil layer thickens, and grasses, wildflowers, and other plants begin to take over http://www.cwrl.utexas.edu
Primary Succession • These plants die, and they add more nutrients to the soil • Shrubs and tress can survive now http://www.rowan.edu
Primary Succession • Insects, small birds, and mammals have begun to move in • What was once bare rock now supports a variety of life http://p2-raw.greenpeace.org