Studying organisms in their environment biosphere

Community Ecology

Inter-species interactions Symbiotic interactions competition (-/-) _______________________________________ 2 species cannot coexist in a community if their niches are identical predation / parasitism (-/+) mutualism(+/+) lichens (algae & fungus) commensalism (+/0) barnacles attached to whale 2005-2006

(+/+) mutualism commensalism (+/0) (-/-) predation (+/-) competition

Resource partitioning Niche _________________________________________ habitat = address, niche = job Resource partitioning

Niche & competition Competitive Exclusion ___________________________________________________________________________________

Predation drives evolution Predators adaptations ___________________________ Prey adaptations ___________________ horns, speed, coloration spines, thorns, toxins

Energy flows through ecosystems sun secondary consumers (carnivores) loss of energy loss of energy primary consumers (herbivores) producers (plants)

Effects of deforestation 40% increase in runoff loss of water 60x loss in nitrogen 10x loss in calcium loss into surface water 80 nitrate levels in runoff 40 loss out of ecosystem! of nitrate (mg/l ) Concentration 4 Deforestation 2 Why is nitrogen so important? 1965 1966 1967 1968 Year

Food chains sun Trophic levels feeding relationships Tertiary consumer Trophic levels feeding relationships start with ______________ ______________________. captured by ___________ 1st level of all food chains food chains usually go up only 4 or 5 levels inefficiency of energy transfer all levels connect to ___________________. top carnivore Level 3 Secondary consumer carnivore Level 2 Primary consumer heterotrophs herbivore Level 1 Producer autotrophs Fungi Decomposers Bacteria

Trophic structure Food chains feeding relationships food chain usually 4 or 5 links = ________________ length of food chain limited by inefficiency of energy transfer

Energy transfer Energy in Energy through from the Sun captured by ____________ = ______________________ Energy through food chain transfer of energy from autotrophs to _______________________ (herbivores to carnivores) heterotrophs = ____________ herbivores carnivores

Inefficiency of energy transfer sun Inefficiency of energy transfer Loss of energy between levels of food chain To where is the energy lost? The cost of living! 17% growth energy lost to daily living only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces)

Pyramids of production _____________________________________________ how much energy is turned into biomass

Ecological pyramid sun ________________________________ can feed fewer animals in each level 1 100 100,000 1,000,000,000

Food webs Food chains are hooked together into ________________ Who eats whom? a species may weave into web at more than 1 trophic level bears “there’s always a bigger fish” What limits the length of a food chain?

Implications Dynamics of energy through ecosystems have important implications for human populations what food would be more ecologically sound? We consume more than just food: water, energy, space/habitat