University:
High School
Course:
High School Biology
Academic year:

2019
Views:

272

Pages:

13
Author:

5CelestialChronicle

Energy Transfer Essential Questions 1. Identify and describe the main types of producers and consumers in an ecosystem. 2. Calculate the amount of energy stored in biomass transferred from one trophic level to another based on a four level energy pyramid with 100 kilograms of energy available at the producer level. 3. Explain why the number of individuals in a population decreases as they get higher in the food chain. Energy Transfer – the passage of energy through the components of an ecosystem • Organisms need energy for: – – – – Growth Movement Maintenance & repair Reproduction • Energy flows through an ecosystem continuously – Energy comes from the sun – Photosynthesis coverts sunlight into chemical energy (food) – Organisms use the energy to live & release energy as heat – Energy is not recycled in ecosystems Producers • Producers are organisms that make food for themselves & everyone else – “Autotroph” is another term for producer! • Types of producers: – Photosynthetic (most common) – use sunlight to make food – Chemosynthetic – use energy from molecules to make food Biomass • Biomass is amount (or mass) of organic material in an ecosystem • This is measured by the amount mass of all of the organic material in an organism, a trophic level or an ecosystem Measuring Productivity • Productivity of an ecosystem can be measured by how much energy is captured from the sun and converted into food – Gross Primary Productivity (GPP) – the rate at which producers in an ecosystem capture energy – Net Primary Productivity (NPP) – the rate at which biomass accumulates (GPP – the respiration rate) • Primary Productivity: – Varies between different ecosystems – Sets the energy limit for the entire ecosystem Consumers • Consumers must eat food made by other organisms (they cannot produce their own food) – “Heterotroph” is another word for consumer • Types of consumers: – Herbivores – eat producers – Carnivores – eat other consumers – Omnivores – eat producers and other consumers – Detrivores – eat decaying material (plant matter, animal waste, etc) – Decomposers – eat dead material & cause decay • Decomposers make organic materials available to producers! Energy Flow • Energy flow diagrams are ecological models representing how energy moves through an ecosystem • Trophic levels – indicate an organism’s position in the sequence of energy transfers Trophic Level Pyramid • Producers (autotrophs) – photosynthetic organisms that make their own food • Primary consumers – herbivores that consume producers • Secondary consumers – small carnivores or omnivores • Tertiary consumers – large carnivores or omnivores • Quaternary consumers – top of the food chain (not always present) • Decomposers & Detrivores – organisms that consume dead or decaying – Usually bacteria and fungi Food Chain – the sequence of food transfer from organism to organism Food Webs – shows all of the feeding relationships in an ecosystem • Arrows show the direction of energy flow Energy Pyramids – show the cumulative loss of energy from a food chain • 10 % of the energy is passed on to the next level – 10% is the “ecological rule of thumb” – There is some variation in different ecosystems • 90% if the energy is: – used by the organism to sustain life (through cellular respiration) – lost as heat & waste Humans in the Food Web • Omnivores – consume both plants & animals • Primary Consumers – when we eat grains, fruits, veggies & legumes • Secondary Consumers – when we eat beef, chicken & other herbivores • Tertiary or Quaternary Consumers – when we eat fish & other carnivores Essential Questions 1. Identify and describe the main types of producers and consumers in an ecosystem. 2. Calculate the amount of energy stored in biomass transferred from one trophic level to another based on a four level energy pyramid with 100 kilograms of energy available at the producer level. 3. Explain why the number of individuals in a population decreases as they get higher in the food chain.