What is Ecology? Study of the relationship between organisms AND between organisms and their environment

Abiotic vs. Biotic Factors Abiotic (nonliving) - soil, temperature, sunlight, water, gases, minerals, etc. Biotic (living) - any organism

Organization of the Living World Biosphere Ecosystem Community Population Individual

Population All the members of the same species that live in the same area

Community All populations of organisms living in the same place

Ecosystem All biotic and abiotic factors in a particular environment

BIOSPHERE All regions of the earth where life can exist

Energy Flow through an Ecosystem Food Chains and Food Webs

Energy Flow The source of all energy on earth is the sun The sun’s energy is trapped by plants in photosynthesis and transformed into carbohydrates Energy is measured in calories (kcal)

How do organisms get energy? The trophic levels Producers (autotrophs - make their own food) Consumers* (heterotrophs - get food from their environment): - primary (herbivores - eat only producers) - secondary (eat primary consumers) - tertiary (eat secondary consumers) *A consumer can be all three types at the same time (omnivore)

Food Chains and Webs Show the path of energy through an ecosystem Arrows follow the direction of energy flow All food chains and webs have producers at the base

Food Webs Food webs show many food chains and how they are connected to each other Food webs are more accurate representations of the true relationships between organisms

Energy Flow in a Food Web At each step in the food chain, 90% of the energy is lost as heat Each organism in the chain receives 10% of the energy from the organism it consumes (except for producers which get their energy from the sun) In the diagram above, only 10% of the available energy is passed on to each trophic level

Pyramid of Energy and Biomass Biomass - total amount of living tissue

Pyramid of Energy and Biomass producers Primary consumers Secondary consumers Tertiary consumers Decreasing biomass Decreasing energy

Cycling of Nutrients vs. Energy Nutrients are recycled Energy is not recycled Nutrients are recycled Energy is not recycled

Water cycle evaporation precipitation Transpiration (excess water exits through leaves as water vapor) runoff Condensation to form clouds Uptake through roots The Water Cycle groundwater

CO 2 (air) ConsumersProducers Carbohydrates (photosynthesis) photosynthesis respiration decomposers Death & decay respiration Fossil fuels (oil, coal) Millions of years, high pressure and temperature Factories, cars Used as energy for combustion CARBON CYCLE

N 2 (gas) nitratesammonia Bacteria change ammonia into N 2 fixing bacteria change N 2 gas into plants Used by Consumers Eaten by ammonia Decomposition After death Denitrifying bacteria Change nitrates to N 2 gas NITROGEN CYCLE Decomposition After death Bacteria change ammonia into

Phosphate (soil) Consumers Producers Eaten by Uptake through roots Die & decompose Aquatic producers and consumers die Body of water (lakes, oceans, etc.) PHOSPHORUS CYCLE Phosphates in soil seep into streams Rocks & sediments Die & decompose

Habitat vs. Niche Habitat - an organism’s environment Niche - an organism’s role in its environment

Niche of Organism A Niche of Organism B Competition When niches of 2 organisms overlap, competition results

Symbiotic Relationships Relationship between two organisms in which one organism benefits

Symbiotic Relationships Mutualism - both organisms benefit from relationship (+,+) Parasitism - one organism benefits at the expense of the other (+, -) Commensalism - one organism benefits while the other is unaffected (+, 0)