5.6: Energy transfers

Systems

Set of interacting or interdependent components

Open System

Resources including chemical substances and energy can enter or exit 

• Ecosystems: open systems as they depend on resources from other organism in their abiotic surroundings 

  • All the organism in an environment and their abiotic environment

  • Like dead matter going down a river

Closed System

Energy can enter or exit but chemical resources cannot be removed

Archaebacteria

used in caves

• Gain energy from chemical reaction that use methane, sulfides or other inorganic compounds as substrates

• Chemosynthesis: The energy is then used to synthesis carbon compounds in this process

Food Chain

Sequences of organism which feed on the previous one

Producers

• Absorb sunlight and convert to chemical energy forming carbohydrates

Autotrophs

•  Use external energy sources (light or chemical) to synthesize their carbon compounds from inorganic substances - self feeding

  • Productes: amino acids, sugar, fatty acids, etc…

  • Produce ATP through cellular respiration

  • Inorganic Substances: CO₂ HCO₃^-, nitrate phosphate etc…

  • Sources of energy: Needed due to the first reduction in the calvin cycle is endothermic

    • Photoautotrophs or chemoautotrophs

Photoautotrophs

Light absorbed by photosynthetic pigments

Chemoautotrophs

Exothermic inorganic chemical reactions

• Substrates in reduced states (S, HS, Fe, H, or NH₃) is oxidized and release energy that is used

• Iron-Oxidizing Bacteria - Acidithiobacillus Ferrooxidans: Remove electrons from Fe²⁺ after FeS₂ reacts with air → forming Fe³⁺  

  • The electron is used to carry energy through the membrane and reduces NAD

  • Or the electron is sued to form water 

Consumers

• Obtain energy by consuming other organism that have them 

  • Primary consumers eat producers, secondary consumers eat primary consumers

Heterotrophs

•  Gain nutrients through other organism 

Assimilation

• Process of absorbing carbon compounds and making them part of the body

  • Molecules must be small and soluble 

• Produce ATP by cell respiration 

Apex Predator

• On the top of the food chain - nothing eats it

Decomposer

• Dead organisms are digested by decomposers like saprotrophs 

  • Saprotrophs put their enzymes in the dead organism and digest it externally first before taking in its nutrients

  • Their hyphae secretes the enzymes out 

Making food chains

complex and in actuality it's more web like - often eat many different trophic levels 

• Levels of the web show trophic levels but the arrows can go anywhere

• Energy pyramid: Shows the amount of energy gained by each trophic level per year 

  • Measured in unit area per year →