Unit #10: Ecology (Part 4) ECOSYSTEMS Ms. Day AP Biology

Introduction to Ecology Study of interactions between living and non living things. Explains how living organisms affect each other and the world they live in.

Habitat & Niche Habitat is the place a plant or animal lives “the address” Niche is an organism’s role in life “its address and its job” All resources used by that organism

Biotic Factors of the Biosphere ALL LIVING PARTS OF AN ECOSYSTEM Think: “BIO” means “life” Plants Animals Fungi Decomposers I’m BIOTIC!!!

Abiotic Factors of the Biosphere ALL NON-LIVING PARTS OF AN ECOSYSTEM Think: “A” means “anti/against” Climate Water/Rainfall, Light, Temperature, Wind/air currents Rocks and soil Particle size, Mineral composition, pH Periodic disturbances fire, flood, earthquake, etc.

Organizing life Interactions between organisms fit in into different levels according to complexity

LEAST inclusive (SPECIFIC) MOST inclusive (BROADEST) Levels of Life ORGANISM 1 living thing: made of cells/DNA, uses ATP, reproduces, responds to stimuli, grows/develop SPECIES group of the same organisms that can interbred POPULATION group of the same organisms living in the same place at the same time that can interbreed COMMUNITY group of the DIFFERENT organisms (populations) living in the same place at the same time ECOSYSTEM (includes BIOMES) All abiotic (nonliving) and biotic factors in an area BIOSPHERE = all the ecosystems together on Earth MOST inclusive (BROADEST)

TERRESTRIAL BIOMES

Trophic Structure in Ecosystems Ecosystems divided into trophic levels (feeding levels) Primary producers—autotrophs (mostly photosynthetic but can be chemosynthetic) Primary consumers—herbivores Secondary consumers—carnivores that eat herbivores Tertiary consumers—carnivores that eat other carnivores Detrivores/Decomposers—consumers that eat dead or decaying matter

Food Chain: shows energy pathway Arrow head = predator Arrow tail = prey

Food Webs Feeding relationships woven into elaborate interconnec-tions between species

Sun = GENERALLY supplies all energy to ecosystems RECALL… Sun = GENERALLY supplies all energy to ecosystems

Energy Flow in Ecosystems Each level has different amount of stored chemical energy When you go UP a level, some energy is lost Gross primary productivity (GPP)= total chemical energy made by producers TOTAL PHOTOSYNTHESIS (adds biomass) Net primary productivity= total chemical energy – energy used for cellular respiration by plants TOTAL PHOTOSYNTHESIS -CELLULAR RESPIRATION

CALLED 10% rule (trophic efficiency) ~10% of energy at each level converted to new biomass CALLED 10% rule (trophic efficiency)

Biomass = amount of living matter in a given habitat LOTS OF BIOMASS HERE

Toxins in the Environment In some cases, harmful substances persist for long periods in an ecosystem One reason toxins are harmful is that they become more concentrated in successive trophic levels biological magnification toxins concentrate at higher trophic levels, where biomass is lower Zooplankton 0.123 ppm Phytoplankton 0.025 ppm Lake trout 4.83 ppm Smelt 1.04 ppm Herring gull eggs 124 ppm Concentration of PCBs