Biology 10/2/13 Mrs. Turgeon
DO NOW: In your notes: Fill in theblanks regarding a Biologist’s levelsof organization:
1.____________2.Bio molecule 3. ____________4. Cell
Biology 10/2/13 Mrs. Turgeon
AGENDA
1.Make a class list: Rules of a good graph
2. Discuss Bee article in groups
Nutrition & Energy Flow
Chapter 2, Section 2
How are these items related to one another in an ecosystem?
How Organisms Obtain Energy
• The Sun is the ultimate source of energy for life.
Producers
• Photosynthetic Autotrophs– Use light energy to make glucose
Consumers• Heterotrophs
– Herbivores = feed only on plants
– Carnivores = eat other heterotrophs
– Scavengers = eat dead animals
– Omnivores = eat both animal and plant materials
– Decomposers = break down and release nutrient from dead organisms
Flow of Matter and Energy in Ecosystems
• Models to show how energy moves in one direction through an ecosystem– Food Chains– Food Webs– Ecological Pyramids
Food Chain
• Arrows show transfer of energy (…is eaten by)
Ex: berries mice rattle snake– A portion of energy is given off as heat at each
transfer– Amount of energy in final transfer is only a fraction
of what was at the first transfer• Only 10% of energy is transferred between each level
• Trophic Levels = Each organism represents a feeding step in the movement of energy
Food Web
• Shows all possible feeding relationships at each trophic level in a community
Ecological Pyramids
• Base always represents 1st trophic level
• Higher trophic levels are layered on top of one another
• Pyramid of Energy = Energy decreases with each trophic level moving up– Total energy transfer from one trophic level to
the next is only about 10%
• Pyramid of Biomass = Less living material as you move up trophic levels
Cycles in Nature
• Matter moves through the trophic levels of an ecosystem.
• Energy can be lost through heat; Matter is not gained or lost, it is recycled.
• Ex: Water Cycle, Carbon Cycle, Nitrogen Cycle, Phosphorous Cycle
Water Cycle
• Water present 3 billion years ago is still present today
• It’s been recycled between land, ocean and atmosphere– Evaporation (water gas)– Condensation (clouds)– Precipitation (rain)
The Carbon CyclePutting Carbon in the Ground:• Plants use CO2 to create carbon compounds
(sugar) for growth and energy• Consumers eat plants and/or other animals to
get carbon compounds for growth and energy• Plants and animals die, carbon is returned to the
ground where fossil fuels can form
Putting Carbon in the Atmosphere:• CO2 gets released during cell respiration• CO2 released when burning fossil fuels
The Nitrogen Cycle
• See figure 2.19 on page 56
The Phosphorous Cycle
• See figure 2.20 on page 57
Practice• Why is a pyramid a good shape to
represent how matter and energy transfer in an ecosystem? Why not use a circle or a square?
• According to the Law of Conservation, matter can neither be created nor destroyed. Make a relationship between this statement and the recycling of carbon in an ecosystem. (Hint: All life on this planet is carbon based. What happens to a tree that dies & falls in a forest? Who benefits from the dead tree?)