Ecology

• Ecology- Science of the interactions between organisms and their environment

Principles of EnergyEnergy- The ability to do work

•Matter- Everything that takes up space and has mass–Conservation of matter: matter can be transformed, but never destroyed

•Thermodynamics- Study of how energy is transferred

Laws of Thermodynamics

• First Law- Energy is conserved– Energy cannot be destroyed, only moved

around

• Second Law- With each transfer of energy, less energy is available for work– Entropy: all natural systems move from a

state of order to one of disorder

Energy and Ecosystems

• Ecosystem- Organisms interacting with environment and each other through a food chain

• Biomass: Matter contained in living organisms. Represents both matter and energy

Energy moves through ecosystems while matter is cycled.

Biomass

Photosynthesis and Respiration

• Photosynthesis: Producers (plants) use sunlight to build biomass out of water, CO2,, and nutrients (ammonia, nitrate, phosphate)– Used for growth, reproduction and energy

storage

• Respiration: Consumers (animals) break down biomass to release energy– Used for growth and reproduction

Decomposers and Detritivores

• Decomposers break down non-living matter and release nutrients that can be used by plants to make biomass– Ex: Fungi, bacteria

• Detritivores eat the waste productsor dead bodies of other organisms– Ex: Worms

Decomposers and Detritivores

Food Chains

• Food Chain- Energy and matter move from one organism to another as each eats a lower member and, in turn, is eaten by a higher member

Trophic Levels

• Each ‘link’ in the food chain is called a trophic level. (troph means food) – 1st =Primary Producer

• Ex: plants, algae

– 2nd = Primary Consumer• Ex: Grazer, herbivores

– 3rd = Secondary Consumer• Ex: Carnivores

– 4th = Tertiary Consumer, etc…

• At each level, detrivores and decomposers are turning biomass into nutrients

• Because organisms consume at various trophic levels, it is really more like a web, not a chain.

Food Web

Ecological Efficiency and Ecological Pyramids

• About 90% of biomass is lost when transferred from between trophic levels– Ecological efficiency= 10%

• As trophic levels increase, biomass decreases– Why there are more squirrels than wolves in

the world

Ecological Pyramid

2° Consumers

3° Cons.

1000 g Biomass

100 g

10 g

1 g

Primary ProducersPrim

ary Consumers

Biogeochemical Cycles

• Hydrological Cycle: the path of water through the environment

• Carbon Cycle: carbon is used to make all biomass. It is a structure component for molecules and also stores energy

Hydrological Cycle

Carbon Cycle