Chapter 18 Interactions of Living Things

Photosynthesis is the process by which green plants use light, water, and carbon dioxide to make sugar, oxygen, and water In photosynthesis, solar energy is converted to chemical energy. The chemical energy is stored in the form of glucose (sugar). Carbon dioxide, water, and sunlight are used to produce glucose, oxygen, and water. The chemical equation for this process is: 6CO H 2 O + light → C 6 H 12 O 6 + 6O 2 + 6H 2 O

Producer Primary Consumer Secondary Consumer Tertiary Consumer

Loss of Energy in Food Chains  Each trophic level (level of the food chain) gets only about 10% of the level before it.  So if we start with 100% of the sun’s energy:  10% is captured by green plants, which use 9%  1% goes to the primary consumer, which uses.9% .1% goes to the secondary consumer, which uses.099%  Only.001% is left for the tertiary consumer

So what does that mean in terms of food?  A tomato leaf gets 10,000 energy units from the sun. It uses 9,000 units.  An aphid eats the tomato leaf and gets 1,000 units of energy. It uses 900 units.  A ladybug eats the aphid and gets 100 units of energy. It uses 90 units  A small bird eats the ladybug and gets 10 units of energy. It uses 9 units.  A fox eats the bird and gets 1 unit of energy.

Niche  An organism’s niche is the role it plays in an ecosystem.  General Examples: predator, prey, producer, parasite, primary consumer, herbivore, omnivore  Specific examples: what cleans the tentacles of a sea anemone? What eats the mosquitoes near a lake? What is food for the tiger in India?