Ecology Week 1Ecology Week 1Chapter 50: Introduction to Ecology and the Biosphere

Chapter 54: EcosystemsJ Liu

September ___, 2008

Big to SmallBig to Small

Water BiomesWater Biomes

• Lakes—oligotrophic, eutrophic; littoral/ limnetic zones

• Wetlands

• Streams and Rivers

• Estuaries

• Intertidal Zones

• Oceanic Pelagic Biome

• Coral Reefs

• Marine Benthic Zone

Land BiomesLand Biomes

• Tropical Forest

• Desert

• Savanna

• Chaparral

• Temperate Grassland

• Coniferous Forest

• Temperate Broadleaf Forest

• Tundra—permafrost

Seasonal TurnoverSeasonal Turnover

• Spring and fall

• Switch oxygen rich and nutrient rich water

• Thermocline

Ecosystems! Some Basics.Ecosystems! Some Basics.

• Are made up of all the biotic (alive things) and abiotic (immortal, not alive things) in a community

• Nutrients are cycled; energy isn’t

“Trophic Relationships” (a.k.a. Food Chains)

“Trophic Relationships” (a.k.a. Food Chains)

• Autotrophs (primary producers)

• Heterotrophs (primary, secondary, and tertiary consumers)

• Detritivores (decomposers)

• Yum! :D

Limiting Primary ProductivityLimiting Primary Productivity

• Primary production—amount of light energy converted to chemical energy per time

• Little energy from the sun is made use of

• NPP = GPP – R

• In water: photic zone, upwelling, and eutrophication

• On land: actual evapotranspiration

• In general: limiting nutrients, especially nitrogen and phosphorus

Production (In)efficiencyProduction (In)efficiency

• Secondary production—how much chemical energy becomes new biomass

• Production efficiency = NSP / APP

• Trophic efficiency—how much energy is transferred to the next trophic level

• Pyramids (production, biomass, numbers)

The Green World HypothesisThe Green World Hypothesis

• Herbivores don’t eat all the plants because other things kill them first

• Plant defenses, limited nutrients, abiotic factors, competition (inter-/intra- specific)

Biogeochemical CyclesBiogeochemical Cycles

• So called because they involve biotic and abiotic components

• Global versus local

The Water CycleThe Water Cycle

The Carbon CycleThe Carbon Cycle

The Nitrogen CycleThe Nitrogen Cycle

(It’s too hard to draw)

The Phosphorus CycleThe Phosphorus Cycle

AHHHH this one’s hard to draw too T.T

Human InfluencesHuman Influences

• Moving nutrients from one part of the biosphere to another

• Critical load—the amount of a nutrient that can be absorbed by plants without damaging the ecosystem

• Cultural eutrophication

Acid RainAcid Rain

• pH less than 5.6

• Lowers pH of water, changes soil composition

ToxinsToxins

• Biological magnification—toxins become more concentrated in higher trophic levels

• Stay in the environment for a long time

Carbon Dioxide in the AtmosphereCarbon Dioxide in the Atmosphere

• C4 plants replaced by C3 plants

• Greenhouse effect—reflection of infrared back to Earth by carbon dioxide and dihydrogen monoxide ( ^^ )

The Ozone LayerThe Ozone Layer

• Protects the surface from UV

• Depleted by CFCs

• Chlorine is a catalyst

• Skin cancer and cataracts