Transfer of Energy Chapter 3-2 Ecology Notes 2 Transfer of Energy Chapter 3-2

Ecosystem Inputs nutrients cycle inputs energy nutrients biosphere energy flows through constant input of energy nutrients cycle Matter cannot be created or destroyed Don’t forget the laws of Physics! nutrients can only cycle inputs energy nutrients

1. Energy Transfers In an ecosystem, energy flows in this manner: SUN  AUTOTROPHS(photosynthesis)  AUTOTROPH PREDATORS  OTHER PREDATORS How much energy is cycled from organism to organism structures an ecosystem?

2. The Producers PRODUCER – an autotrophic organism; one capable of capturing energy to make its own food Producers create BIOMASS (ORGANIC MATERIAL) in an ecosystem Examples - on land, plants; in water photosynthetic bacteria Energy Gathering processes PHOTOSYNTHESIS - organisms capture energy from the sun CHEMOSYNTHESIS – organisms get energy from inorganic molecules

3. Productivity Productivity is the rate at which producers convert solar energy into chemical energy GROSS PRIMARY PRODUCTIVITY (GPP) – How quickly producers gather energy Energy is used for cellular respiration and for reproduction (a process that creates biomass, organic stuff ) NET PRIMARY PRODUCTIVITY (NPP) – How quickly biomass accumulates Non-autotrophic organisms can only access energy stored as biomass, not the energy producers use to stay alive NPP = GPP – cellular respiration rate of producers Unit = kilocalorie/meter2/year

3. Productivity -Certain ecosystems are MORE productive than others RAIN FORESTS account for 30% of the world’s primary productivity Productivity depends on TEMPERATURE, PRECIPITATION and LIGHT Water ecosystems depend on LIGHT and TEMPERATURE only

4. The Consumers -CONSUMER– heterotrophic organism; one that eats other organisms and waste products HERBIVORES – Plant eaters CARNIVORES – Meat eaters OMNIVORES – Meat and plant eaters DECOMPOSERS – Break down non-living organic matter Scavengers: seek dead organisms for food Detritivores: decompose and feed of dead organisms and organic waste products

5. Food Chains vs. Food Webs -FOOD CHAIN– a linear representation (line) of feeding relationships between organisms in an ecosystem Example – GrassZebraLion Grass = PRODUCER Zebra = PRIMARY CONSUMER Lion = SECONDARY CONSUMER

Food Chains sun Trophic levels feeding relationships Tertiary consumer top carnivore Level 3 Secondary consumer Trophic levels feeding relationships start with energy from the sun captured by plants 1st level of all food chains food chains usually go up only 4 or 5 levels inefficiency of energy transfer all levels connect to decomposers carnivore Level 2 Primary consumer heterotrophs herbivore Level 1 Producer autotrophs Fungi Decomposers Bacteria

5. Food Chains vs. Food Webs -FOOD WEB – a diagram of all interrelated food chains in an ecosystem Example: The zebra eats the grass, but so does a mouse. Lions eat zebras, but mice are more worried about snakes than lions. The insects feeding off the grass have to worry about bird predators…get the idea?

5. Food Chains vs. Food Webs A sample food web…Can you pick out the individual food chains?

A sample food web…Can you pick out the individual food chains?

6. Trophic Levels and Energy Pyramids TROPHIC LEVEL – an animal’s position on an energy pyramid ENERGY PYRAMID – a diagram showing how energy is transferred from producer to primary consumer to secondary consumer etc… Typically, the amount of energy transferred from one level to the next is only 10% of the level below it. There are typically MORE producers than consumers in an area because less energy is available for the higher-level consumers to sustain a large population.

Ecological Pyramid sun Loss of energy between levels of food chain can feed fewer animals in each level Numbers 1 100 100,000 1,000,000,000

Inefficiency of Energy Transfer sun Inefficiency of Energy Transfer Loss of energy between levels of food chain To where is the energy lost? The cost of living! 17% growth energy lost to daily living only this energy moves on to the next level in the food chain 33% cellular respiration 50% waste (feces)

6. Trophic Levels and Energy Pyramids Shows the relative amount of energy available at each trophic level. Organisms use about 10 percent of this energy for life processes. The rest is lost as heat. Pyramid of Numbers Shows the relative number of individual organisms at each trophic level. Biomass Pyramid Represents the amount of living organic matter at each trophic level. Typically, the greatest biomass is at the base of the pyramid.

Energy Pyramid

Energy Pyramid On your Energy pyramid, label these items: Primary Producers, Primary Consumers, Secondary Consumers, and Tertiary Consumers. What do you notice about the secondary vs. tertiary consumers? What is the difference in energy between the producers and the primary consumers? How about the difference between the producers and the tertiary consumers? List the food chain present in this diagram starting with the producer.