Campbell 54 - Chapter 54 Ecosystems What is an Ecosystem?...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 54 Ecosystems
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
What is an Ecosystem? All organisms living in an area plus the abiotic factors Energy machines and matter processors Energy flows through and matter cycles
Background image of page 2
Trophic Relationships Primary producers Ultimately support all trophic levels Autotrophic organisms Organisms above producers Heterotrophic Depend on photosynthetic output of producers Decomposers Get energy from detritus (nonliving organic material) Play a central role in material cycling
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Decomposition’s Role Decomposers link all trophic levels Re-supply ecosystems with organic material Liberate otherwise unusable material Earthworms eat soil and extract nutrients and birds eat worms Worms cant eat dirt
Background image of page 4
Laws of Physics and Chemistry First law of thermodynamics Energy is neither created nor destroyed, only transformed Second law of thermodynamics Energy is lost when it changes states Chemistry laws Energy moves through an ecosystem Nutrients cycle through an ecosystem
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Primary Producers Organisms that convert energy from the sun into chemical energy (stored in bonds of sugars) Primary producers provide all the energy for a given ecosystem Lots of plants means lots of energy
Background image of page 6
Global Energy Budget Each day Earth receives 10 22 joules of solar radiation Equivalent of 100 million atomic bombs Most of that energy is reflected by the atmosphere, or absorbed by water or the ground Plants only use the part of solar radiation we call visible light Of visible light only 1% is converted to organic matter But producers generate 170 billion tons of organic matter a year
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gross and Net Primary Production Gross Primary Production Amount of light energy converted to chemical energy by photosynthesis per unit of time Not all of this production is stored as organic material because the plants use some molecules as fuel for respiration Net Primary Production Amount of chemical energy available to the next trophic level NPP = GPP – R (respiration)
Background image of page 8
Net Primary Production Measurement of most interest to ecologists Primary production can be expressed as biomass (weight of vegetation added to ecosystem per area per time or g/m 2 /yr) or energy per area per unit time or (J/m 2 / yr)
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Earth’s Ecosystems and Biomass
Background image of page 10
Production in Marine Ecosystems Limiting factors in Marine Ecosystems Light – more than half the light is absorbed in the first meter of water Even clear water at 20 m only 5-10% of the light is available We should then see an increase in production from poles toward the equator but we don’t Its actually nutrients that are more limiting in marine ecosystems than light
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 43

Campbell 54 - Chapter 54 Ecosystems What is an Ecosystem?...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online