13.1 Ecologists Study Relationships

• Remember cellular levels of organization?– Atom, molecule, cell, tissue, organ, organ system,

organism• Environments have levels of organization too:– Organism, population, community, ecosystem,

biome

• Observations– Remember: QuaLitative and QuaNtitative Data– Short-term or Long-term studies (Darwin!!!)– Visual Surveys: direct (scope) or indirect (footprints)

• Experimentation- direct study of organisms– Lab: more control, less complex results– Field: more accurate results (not always cause/effect)

• Modeling– Computer/math-based – Uses lots of data to make predictions– Quick lab/estimations

13.2 Biotic and Abiotic Factors

• Biotic- living • Abiotic- “a”=not, nonliving

Match the following environmental factors as biotic or abiotic:

Rock Oxygen SalinitySponge Fern MulchShark Squirrel LillySunflower Sand PantherWater Mangrove Tree Apple

keystone

• Biodiversity– Variety of life in an ecosystem– Why do we care? __________________________

• Keystone Species– Keystone holds up an arch– Species has great effect on/in ecosystem– Why do we care? __________________________– (Multimedia activity)WebQuest: Keystone species • Use the information you’ve learned to predict what

would happen if sea otters went extinct.

13.3 Energy in Ecosystems

• Producers = Autotrophs (make own food)– Remember photosynthesis??– Also chemosynthesis: use chemical instead of sun

• Consumers = Heterotrophs (must eat something else)– Herbivores- eats plants (herba = vegetation)– Omnivores- eats plants and animals (omna = all)– Carnivores- eats animals (carnus = flesh)– Detritivores- eats dead organic matter– Decomposers-break down organic matter

• (Animation/simulations: visual concepts- 13.3)– 2 facts from each visual you watch

13.4 Food Chains and Food Webs• Hey don’t write this first note you already did• Consumers = Heterotrophs (must eat something else)

– Herbivores- eats plants (herba = vegetation)– Omnivores- eats plants and animals (omna = all)– Carnivores- eats animals (carnus = flesh)– Detritivores- eats dead organic matter– Decomposers-break down organic matter

• Food chains show energy flow• Food webs show complex feeding relationships• Specialist- specific food type (1 or few

organisms)• Generalists- eat variety of foods in diet

• Trophic Levels– Primary: autotrophs/producers– Secondary: herbivores – Tertiary: omnivores and carnivores

• Online: Animation- Build a food web (sketch web)

13.5 Cycling of Matter• Attach bunches of those little pictures • Next to each picture we are going to write

how elements enter/exit the system• Hydrologic Cycle– Enter: evaporation (bodies of water), transpiration– Exit: condensation/precipitation, used

plants/animals• Biogeochemical Cycle– How elements are cycled through biotic and

abiotic parts of environment

• Oxygen Cycle– Enter: autotrophs from photo-/chemo-synthesis– Exit: used by humans or in soil as nutrients

• Carbon Cycle:– Enter: CO2 (atm), HCO3 (in water), fossil fuels/in

ground, oil, natural gas, rocks, dead organic matter– Exit: burning fossil fuels, plants, evaporation

• Nitrogen Cycle:– Enter: bacteria, atmosphere, decomposing plants– Exit: animals, plants

• Phosphorous Cycle:– Enter: geologic movements, decomposition – Exit: leaching, weathering, sedimentation

energy transferredenergy

lost

13.6 Pyramid Models• Energy pyramid- E used

by producers/consumers• Biomass- total dry mass

of all organisms in area• Each tier loses 90% of E =

ONLY 10% of E is transferred from each trophic level!!!

• Biomass pyramid– Dry mass of tropic levels– Mass of comsumers

needed to support levels above them

• Pyramid of Numbers – Numbers of individuals– Vast #’s of producers are

needed to support even just a few tertiary consumers

– Animations: Visual concepts 13.6 (2)

tertiaryconsumers

secondaryconsumers

primaryconsumers

producers

75 g/m2

150g/m2

675g/m2

2000g/m2producers 2000g/m2

tertiaryconsumers

secondaryconsumers

primaryconsumers

producers

5

5000

500,000

5,000,0005,000,000producers