NUTRITION AND ENERGY FLOW CHAPTER 2.2 Martin 2010/2011

Objectives Compare how organisms satisfy their nutritional needs Trace the path of energy and matter in an ecosystem Analyze how matter is cycled throgh in the abiotic and biotic parts of the biosphere

I. HOW ORGANISMS OBTAIN ENERGY Animals usually “feed” off of another source How organisms obtain energy is important characteristic called its “niche” Two types of “feeders”  Autotrophs  Heterotrophs

I. HOW ORGANISMS OBTAIN ENERGY A. The Producers: Autotrophs Autotroph: uses light energy (from sun) to make energy-rich compounds Sun is ultimate source of energy for life Autotrophs are usually plants, shrubs, trees, green algae

I. HOW ORGANISMS OBTAIN ENERGY B. The Consumers: Heterotrophs Heterotroph: organism that cannot make its own food and feeds on other organisms 4 types of heterotrophs  Herbivores: feed only on autotrophs (plants, shurbs, grasses, etc)  Carnivores: feed only on “meat” based organisms  Omnivores: feed on both “meat” and “plant” based organisms  Decomposers: mushrooms, fungi, bacteria

I. HOW ORGANISMS OBTAIN ENERGY B. The Consumers: Heterotrophs Decomposers: break down dead, and decaying, organic material  the substances broken down are reabsorbed by the soil and returned to the autotrophs as nutrients  **“THE RECYCLERS”** in the flow of energy

II. FLOW OF MATTER AND ENERGY IN THE ECOSYSTEM Matter and energy are neither created or destroyed  They flow in and out of our system and the Earth’s system A. Food Chains: Pathways for matter and Energy Food chain: a simple model that scientists use to show how matter and energy move through an ecosystem  Shows movement from autotrophs through heterotrophs and eventually to decomposers

II. FLOW OF MATTER AND ENERGY IN THE ECOSYSTEM Grass  grasshopper  frog  snake  hawk  Where does the grass get its energy? Energy is transferred between each organism Energy transferred is less and less as we move from grass to hawk  HEAT IS RELEASED in each step in the chain  The heat released is 90% of the energy  Only 10% is transferred to the next animal

II. FLOW OF MATTER AND ENERGY IN THE ECOSYSTEM B. Trophic Levels Represent Links in the Food Chain Trophic level: each step in the food chain (each level in the energy pyramid)  Usually at most 4 trophic levels ▫Autotroph ▫1 st order heterotroph ▫2 nd order heterotroph ▫3 rd order heterotroph

II. FLOW OF MATTER AND ENERGY IN THE ECOSYSTEM C. Food Webs Food web: a model that shows a more realistic series of food chains linked together  Why is this a more realistic model? ▫Animals eat more than 1 thing.  Shows all possible feeding relationships between animals

II. FLOW OF MATTER AND ENERGY IN THE ECOSYSTEM D. Energy and Trophic Levels: Ecological Pyramids Biomass: the amount of living material present in each trophic level  Decreases as we move up the energy pyramid ▫Because energy is lost as HEAT

III. CYCLES IN NATURE Water Cycle Carbon Cycle Nitrogen Cycle

Water Cycle

Carbon Cycle

Nitrogen Cycle