Ecosystem Ecology Chapter 3

Ecology “study of the interactions between the organisms and their environment”

Wildflower, animals, bacteria Biotic Abiotic Living organisms Nonliving organisms Wildflower, animals, bacteria Sunlight, precipitation, temperature, soil, rock

Flow of Energy Photosynthesis a. Sun + 6 H2O + 6 CO2  C6H12O6 + 6 O2 b. performed by plants, algae, and some bacteria To understand how ecosystems function and how to best protect and manage them, ecologists study the processes that move matter and energy through them. http://www.phschool.com/science/biology_place/biocoach/photosynth/overview.html

Cellular Respiration a. C6H12O6 + 6 O2 Energy + 6 H20 + 6 CO2 b. fuels own metabolism and growth c. aerobic v. anaerobic http://bcs.whfreeman.com/friedlandapes/#t_668210____

Trophic Levels/Feeding Levels

Food Chain v. Food Web http://bcs.whfreeman.com/friedlandapes/#t_668210____ (modified http://bcs.whfreeman.com/friedlandapes/#t_668210____ (modified)

a. consume dead animals (vulture) Detritivores Scavengers a. consume dead animals (vulture) Detritivores a. break down dead tissues and waste products into smaller particles (dung beetles) Decomposers a. complete the breakdown process by recycling the nutrients from dead tissues back into the ecosystem (fungi, bacteria) Not all organisms fit neatly into a single trophic level. Each level produces dead individuals and waste products that feed other organisms.

Gross Primary Productivity ex) total paycheck Net Primary Productivity ex) paycheck after taxes GPP: total amount of solar energy that the producers in an ecosystem capture via photosynthesis over a given amount of time NPP: total amount after the producers have respired

Energy Flow Biomass: total mass of all living matter in an ecosystem Energy is lost at each level (heat) a. 10% gained; 90% lost b. ecological efficiency The NPP establishes the rate at which biomass is produced over a given amount of time Not all energy at each trophic level is in usable form Standing crop: amount of biomass present at a particular time

Matter Cycles Through the Biosphere Biosphere: combination of all ecosystems on Earth Biogeochemical Cycles: movements of matter within and between ecosystems that involved biological, geological, and chemical processes Biosphere: where life is found Remind that earth is an open system for energy and a closed system for matter All of earth’s organisms are composed mostly of carbon, hydrogen, nitrogen, oxygen and phosphorus.

The Hydrologic Cycle Evaporation Transpiration Infiltration Precipitation Condensation evapotranspiration Runoff Evapotranspiration: combination of water evaporation through evaporation and transpiration; used to measure the amount of water moving through an ecosystem http://bcs.whfreeman.com/friedlandapes/#t_668210____

- decreased evapotranspiration, increased runoff b. construction Human Activities a. harvesting trees - decreased evapotranspiration, increased runoff b. construction Earth is closed to matter therefore water never leaves it. Harvesting trees: decreases evapotranspiration from decreasing plant biomass

The Carbon Cycle Photosynthesis Respiration Exchange Sedimentation and burial Extraction Combustion Carbon is the most important element in organisms making up approx 20% of their total body weight Exchange: occurs between ocean and atmosphere * amount of CO2 released from the ocean into the atmosphere equals the amount of atmospheric CO2 that diffuses into the ocean water Sedimentation and burial Dissolved CO2 in ocean combines with the calcium ions in the water to form calcium carbonate (can precipitate out of water and form limestone) Small amounts of organic carbon is buried into sediments and becomes fossilized but later can turned into fossil fuels Extaction Extraction of fossil fuels (doesn’t alter the carbon cycle) Combustion Releases carbone into the atmosphere or into the soil as ash http://bcs.whfreeman.com/friedlandapes/#t_668210____

Humans and the carbon cycle a. combustion of fossil fuels b. deforestation

The Nitrogen Cycle Nitrogen a. proteins and nucleic acids b. useable form  nitrates and nitrites c. earth’s atmosphere  78% nitrogen gas d. most abundant element in the atmosphere

a. nitrogen fixation (nitrogen gas-N2) into ammonia-NH3) Steps a. nitrogen fixation (nitrogen gas-N2) into ammonia-NH3) b. nitrification (ammonia to nitrites and nitrates) c. ammonification (decomposers) d. denitrification e. leaching Nitrate is carried to the earth’s surface through precipitation Ammonification – fungal and bacterial decomposers use the nitrogen-containing wastes and dead bodies as a food source and excrete ammonia Leaching: nitrate ions do not easily bind to soil particles therefore it is transported through the soil with water Denitrification: nitrates that have settled on the bottom of the ocean or in waterlogged soils, denitrifying bacteria convert nitrate into nitrous oxide and then eventually N2 is emitted into the atmosphere http://bcs.whfreeman.com/friedlandapes/#668210__690858__

Human affect Deforestation Fertilizers runoff

Phosphorous Cycle Major component of DNA, RNA and ATP Doesn’t exist in atmosphere a. limited to soil and H2O Has no gaseous component therefore atmospheric inputs are very small Found in: Precipitates out of sediments on the ocean floor or in the weathering of rocks

Steps a. weathering of phosphate rocks b. plants take up phosphate from soil and animals eat the plants c. decomposers release phosphate back in to soil d. animal excretion

Human Influence Fertilizers Runoff into aquatic ecosystem a. excess growth of algae (algal bloom) resulting in hypoxia Found in detergents Excessive algael growth, they eventually die intiating a massive amount of decomposition with consumes lots of oxygen Hypoxia – low oxygen with in turns kills fish and other animals

Calcium, Magnesium, Potassium and Sulfur Important in transmitting signal between cells Derived mostly from rocks and decomposed vegetation Calcium and Magnesium – limestone and marble

The Sulfur Cycle Similar to phosphorous cycle Important for proteins Found mainly in rocks and soil (coal, oil) as minerals

Steps a. Weathering b. plants and animals relationship c. decomposers - sulfates convert to hydrogen sulfide gas which escapes into atmosphere, water, soil, marine sediments * result in acid rain

Human Influence Emissions from coal-burning power plants

Ecosystem Disturbances Disturbance: event caused by physical, chemical, or biological agents that results in changes in population size a. natural and anthropogenic Natural: hurricanes, volcanic eruptions, forest fires Anthropogenic: air pollution, agriculture Ecologists are interested in whether an ecosystem can resist the impact of a disturbace and whether it can recover its original condition (resistance and resilience)

Understanding Biogeochemical Cycles a. helps in determining change by disturbance b. watershed studies - watershed: all of the land in a given landscape that drains into a stream, river, lake, or wetland

Resistance v. Resilience a. resistance: measure of how much a disturbance can affect the flows of energy and matter b. resilience: rate at which an ecosystem can bounce back Not every disturbances is a disaster. Example: low-intensity fire Resistance: when a disturbance influences populations and communities but has not effect on overall flow of energy and matter (HIGH RESISTANCE) Resilience * High – can return back to original within a year

Intermediate Disturbance Hypothesis a. rare disturbances  low diversity b. frequent disturbances  low diversity c. intermediate disturbances  highest diversity Rare disturbances Intense competition among species therefore populations of highly competitive species survive Frequent disturbances Eliminates most species except for those that have evolved to live under those conditions Intermediate Species from both extremes can survive

Ecosystem Services Instrumental Value a. value in terms of how much economic benefit b. ecosystem services c. provisions Intrinsic Value a. moral value of an animal’s life Instrumental It has worth as an instrument or tool Ecosystem services: benefits that humans can obtain from natural ecosystems Provisions: goods that humans can directly use (lumber, food crops) Intrinsic * Has worth independent of any benefit it may provide to humans