Integrated Science 1st Lesson - Energy Transfer PDF

# Chapter one Environmental resources ## Lesson one Energy transfer through ecosystems - **Concept of energy in ecosystems.** - Study the interaction between living organisms in ecosystems and how energy transfers through that system. 1. Fungi feed on dead trees 2. Snake prey o...

# Chapter one Environmental resources ## Lesson one Energy transfer through ecosystems - **Concept of energy in ecosystems.** - Study the interaction between living organisms in ecosystems and how energy transfers through that system. 1. Fungi feed on dead trees 2. Snake prey on a mouse 3. Plant making photosynthesis process - **Energy transfer** - **Solar energy** → **Plant** → **Chemical energy stored in sugar molecules in Plant, glucose.** - $6CO_2 + 12H_2O$ → $C_6H_{12}O_6 + 6O_2 + 6H_2O$ - Light energy - Chlorophyll - Glucose - **Energy transfer through food chains** | Chemical energy | Feed on | Chemical energy | Feed on | |--------------------|-------------------------------------|-------------------------|-----------| | Plant | | Insect | Animal | - However, as energy transfers from one level to another a large amount of it is lost. - Ecologists use food chains and food webs to make models of energy transfer in each ecosystem where each step in the chain is called **trophic level**. - **Autotrophic living organisms.** - always first trophic level - **Heterotrophic living organisms.** - trophic levels higher than level one # Measurement and transfer of energy - The energy transfer pyramid is used to determine the number of living organisms that depend on the same source of energy, and thus we can determine the efficiency of energy transfer. | Level | | |-----------------------|-----------------------------------------| | Producers | 10 | | First Consumer | 6 | | Second consumer | 1 | | 90% is lost through biological processes which consume the largest amount of glucose. | Excretion, respiration | - The energy pyramid rarely contains more than six levels? - Due to loss of energy as the remaining portion of energy is too small to be used as food for another organism. - Therefore, it is better for humans to obtain his food directly from the plant than from an animal that feeds on the plant. # Calculations of lost energy - **Law of Conservation of energy:** Energy neither created nor destroyed but it is converted from one form to another. - **Rabbit gains 100J** | **From a Plant** - Chemical energy → Respiration → $CO_2$ to nature during exhale - Kinetic energy → Helps the animal to move - Thermal energy → Warm the body - Chemical energy → Undigested food → Wastes during excretion - Sum of these energies is equal to 100J which is consistent with the law of conservation of energy. # Lost energy during respiration and excretion = Total energy from the organism's food - energy used in vital processes, as movement and growth # Law of Conservation of energy in food chains - Light energy sun → Plant Photosynthesis → Chemical energy in food → First Consumer chemical energy → Thermal and kinetic respiration - A part is lost in the form of heat - When energy transfers to second consumer that feed on First consumer additional energy is lost during the process of respiration and excretion. - These transformations continue until the energy reaches the decomposers which return the remaining chemical energy from the dead organisms to the soil in the form of salts. # Chemistry in energy transfer - The energy journey begins between living organisms inside the green plants where photosynthesis process occurs inside chloroplasts. Cell organelles specific to plant. - $12H_2O + 6CO_2$ → $C_6H_{12}O_6 + 6O_2 + 6H_2O$ - Water + Carbon dioxide + light → Chlorophyll → glucose + oxygen - Other organisms later use the chemical energy stored in glucose when they feed directly or indirectly on plants. - When glucose (biofuel) is burnt with oxygen inside the organism's body during respiration, heat energy is generated and this energy is responsible for organism's life. - $C_6H_{12}O_6 + 6O_2$ → $6CO_2 + 6H_2O + E$ - Respiratory enzymes # Energy stored in fossil fuels - Fossil fuel: living organisms that stored solar energy directly or indirectly such as coal, petroleum, natural gas. - **Coal:** Remains of trees and plants that decomposed inside earth millions of years ago and composed mainly from carbon. - **Petroleum:** Mixture of several hydrocarbon compounds formed from marine organisms and marine plants buried millions of years ago and decomposed under high pressure and high temperature. - **Natural gas:** Mixture of several hydrocarbon gases found floating on the surface of petroleum in earth's crust or inside coal mines or between rocks and consist of: - Methane gas 70%: 98% - Ethane, propane, butane gases with small proportions - When fossil fuel is burnt with oxygen inside an internal combustion engine, heat energy is generated which is responsible for the movement. # Relation between photosynthesis process and cellular respiration and it's impact on the ecosystem - **1- Ecological balance** - Maintaining the balance between oxygen and carbon dioxide gases in the atmosphere. - Plant → Glucose and Oxygen - Human and animal → Carbon dioxide and water - **2- Energy flow:** - Where solar energy is stored in glucose molecules during the photosynthesis process and when plant is consumed by animal this energy is used in cellular respiration to produce ATP (adenosine triphosphate) molecules inside mitochondria which is the main energy source for all vital processes in living organisms. - **3- Carbon cycle:** - Where carbon dioxide and water are recycled between environment and living organisms.