Chapter 16 - Ecosystems Section 1 –What is an Ecosystem? Section 2 –Energy Flow in Ecosystems Section 3 –Cycling of Materials in Ecosystems

Organisms & their Environment Ecology Study of the interaction between organisms and their physical environment (soil, water & climate) Habitat A location where populations of species resides Community The collection of many species living in on particular habitat Examples

Organisms & their Environment Ecosystem A system that features a community and all its physical environment Abiotic Factors Non-living, physical aspects of a habitat Ex: Soil Biotic Factors Living organisms in a habitat Ex: Trees Examples

Ecosystem Inhabitants Biodiversity Genetic differences of organism, communities and ecosystems Desert: Large organisms: Camel, Red Fox, Jack Rabbit Small organisms: Mice, Snakes Insects: Beetles, Spiders, Red Ants Plants: Cacti, Desert Willow Microscopic organisms in sand Everything works together to have a functional ecosystem

Ecosystem Boundaries Quadrants are usually used for scientific studies Are not just black and white, there are gray areas Dependent on space being studied Ecosystems can be: Enough room for a few species OR many species Ex: Tree or Forest Low OR high possibility of migration Ex: Island or Ocean Quadrants are usually used for scientific studies

Succession Progression of species replacement in a particular area Primary Succession No species have existed in the area before Basically flat land being developed Secondary Succession Growth is reoccurring where growth once was and died off No two succession are alike, every situation and environment is different and the growth is by chance and competition Draw Glacier Bay Example

Primary Energy Source Photosynthetic organism: convert light energy to chemical energy Primary Productivity Rate of organic material being produced by photosynthetic organism Determine how much energy is available to the system Producers Convert light energy into chemical energy Consumers Consume plants or other organisms for energy

Trophic Levels Diagram of energy movement to determine an energy source First Level Food Chain: path of energy (1 to 1) Producer to Consumers

Trophic Levels Second Level Third Level – Secondary Consumers Herbivores Primary consumers – only consume photosynthetic organisms Able to digest cellulose using mutualistic microorganisms Third Level – Secondary Consumers Carnivores Organisms that consume other organisms for energy Omnivores Organisms that consume plants and/or other organisms for energy Detritivores (Decomposers) Obtain energy from dead organic matter or animal wastes

Fourth Level

Loss of Energy Energy Transfer Energy Pyramid From organism to organism some energy is loss as heat The heat loss limits the number organisms receiving energy from the initial source Only 1/10th of the energy is stored within each organism Energy Pyramid The size of the box determines the amount of energy stored Energy is lost from bottom to the top Producers to Top Consumers

Limitations of Trophic Levels Heat Loss - #1 reason for max of four trophic levels Some items require more energy to produce, however provide the same amount of energy One barrel of wheat creates cereal Five barrels fed a pig that creates bacon Biomass Dry weight of organic matter found in an ecosystem Determines the amount of energy available in a system

Biogeochemical Cycle A closed pathway that allows for a living thing to eventually die off and join the non-living environment The energy is never wasted and ALWAYS reused Example: Tree lives for 30 years Dies and is consumed by decomposers Decomposers convert the organic matter to soil and nutrients used for the surrounding trees

The Water Cycle Nonliving Portion (Most important) Water vapor in the atmosphere condenses Falls to the ground as precipitation Some water becomes ground water (retained water in the Earth) Rest of the water is heat and becomes water vapor

The Water Cycle Living Portion Water is taken up by roots Transpires on the leaves – sun heats the surface and wind currents drive the water to the surface Eventually drawn to the air

The Carbon Cycle Cycles between Living and Nonliving Portions Carbon dioxide is used by photosynthetic organisms Carbon returns to the pool of carbon dioxide in 3 ways: Respiration Cellular respiration inhales oxygen Exhales carbon dioxide

The Carbon Cycle Combustion Erosion Sediments transformed by heat Fossil fuel – coal, oil and natural gas Erosion Shells of organism contain dissolved carbon dioxide Sediments of shells – Limestone Exposure and erosion allow carbon to be available

The Phosphorous & Nitrogen Cycle Nitrogen & Phosphorus used to build proteins and nucleic acids Phosphorous reused through eating plants Nitrogen Fixation Assimilation Ammonification Nitrification Denitrification Write definitions on the board