Ecosystems: components, energy flow, and

matter cyclingChapter 3

EcosystemsEcosystems include living and nonliving components

Ecosystems • Living components of the ecosystem:

•Producers (autotrophs)- chemo- and photosynthesizers

•Consumers(heterotrophs)-herbivores,

carnivores, omnivores, detritivores, decomposers

Ecosystems Nonliving components of the ecosystem

•Physical- sunlight, shade, temperature change

•Chemical- level of water or oxygen in the soil, salinity in soil or water

Tolerance Levels

• Range of levels of physical or chemical factors in which an organism can survive

• Can be increased if exposed gradually– *This is acclimation (not passed to offspring like

adaptation)

Threshold EffectThe limit of tolerance is exceededExample: After years of exposure to pollutants, an entire forest dies.

Limiting Factor

• One factor is limiting growth– either too much or

too little• Example: temperature,

nutrient, salinity

Food Chain• general sequence in which animals feed• -Each organism is assigned a trophic level

Primary producer 1st consumer 2nd consumer plant herbivore 1st level

carnivore

Energy Flow Pyramids

• Show useable energy at each trophic level.

• 80-95% of original energy is lost at each level.– What should we

feed starving nations?

Matter and Energy Cycling

Life on earth depends on:One way flow of useable energy to low quality,

dispersed energyhigh quality ___ low quality

Energy (usable) Energy (dispersed)usually solar heat

Matter and Energy Cycling

• Cycling of matter is required by living things

• Sun and gravity drive all cycles

• Light, warmth, energy to grow plants which feed other organisms, weather patterns.

Solar Energy drives Earth’s Cycles• 34% of solar energy

reflected into space• 66 % degraded to heat

(unusable)• Only 0.023% of sunlight

entering our atmosphere is used by green plants and some bacteria for photosynthesis (storing the energy from the sun as carbohydrates)

Nutrient Cycles

• Nutrients- elements needed by organisms to live and reproduce.

“Macro” means it is needed in large amounts• Ex. Oxygen, N,H,P,D,Ca

“Micro” means it is needed in small amounts• Ex. Zn, I, Fe

*All nutrients cycle through living and nonliving systems and are converted to useable forms

*We are using the same atoms as those from when life began!

Carbon Cycle

• Needed for carbohydrates (food/energy)

• We intervene Green House Effect- add more CO2 to atmosphere than is being removed, by burning fossil fuels and trees.

•

Nitrogen Cycle

• Needed to make proteins

• We intervene: Add NO (burning fossil fuel) or excess NH3 (ammonia fertilizer) and NO2 (bacteria and fertilizers.)

Phosphorus Cycle• needed for DNA,

ATP, bones, teeth, some fats

• moves slowly (not a gas)

• limiting factor in many soil and aquatic systems

Phosphorus Cycle

• We intervene:• -Mining PO4 for

fertilization and detergents (decrease in one area means an increase in another)

• -Untreated sewage dumped into ocean

• -Runoff of animal waste and fertilizer

Sulfur Cycle

Needed in proteinsWe intervene

-Burn fossil fuels-Refining petroleum-Use smelting to convert sulfur compounds of metallic mineral into free metals such as copper, lead, and zinc.

Water Cycle

• Needed for major component of cells

• and for all life processes

• Temp is very important• Increase temp=

increase evaporation• Decrease temp=

condensation

Water Cycle

• We intervene:• -Drawing large amts. Of

ground H2O

• -Intrusion of salt H2O in underground supplies

• -Cutting forests and paving roads.