Ecology – Living things and the Environment Chapter 5 & 37 Unit #1 Ecology – Living things and the Environment Chapter 5 & 37

“Big Idea” Living things need to obtain & use energy in order to do work! Where do they get this energy from? Ecology – the study of how living things interact with each other & their environment

What do we call the energy in our food? Calories Measure the amount of energy stored in your food Where is the energy stored in your food? Molecules that are bonded together to make that food. Bonds are a form of chemical energy!

Bonds When you break a bond… When you make a bond… You release energy! Decomposition Exergonic Reaction When you make a bond… You store energy! Synthesis Endergonic Reaction

Is anything 100% efficient? Not all the chemical energy stored in food can be used to do work. The portion of chemical energy you can use (or that is “free”) to do work is called: free energy The more free energy you can obtain from what you eat, the more efficient you are! Any free energy left over (after you have done your work) is then stored.

Basically 2 ways living things get this energy… Heterotroph Obtain energy from other living things. AKA  EAT Cellular Respiration Autotroph Use surrounding to make their own food! Plants  photosynthesis Bacteria  chemosynthesis

Energy & Ecosystems Would a deer come running out of the woods and try to eat you? Why? Organisms have certain roles! Autotrophs – producers Heterotrophs – consumers Special Case – Decomposers (consume dead or decaying matter) Bacteria, fungi, worms, vultures Recycle important nutrients (not energy!) back into soil for producers such as plants to use again

Types of Consumers Trophic Levels If you eat plants (herbivore) you are a primary (1o) consumer If you eat herbivores (carnivore) you are a secondary consumer (2o) If you eat 2o consumers then you are a…. Trophic Levels

Food Web More Realistic than chain Display the flow of energy through an ecosystem Arrow points in the directions the energy is traveling! Ecosystem – all the living & nonliving things in an area All Living Things – Biotic Factors All Non Living Things – Abiotic Factors

Some More Vocab… Habitat – places where particular organisms live Niche - organism’s role in its environment

The Re-Introduction of Wolves

The mouse population would most likely increase if what happened? What would cause the mouse population to decrease? Using this information, why do you think we have such an overpopulation of deer in New Jersey?

Laws of Thermodynamics Study of Energy Changes 1st Law – energy cannot be created or destroyed, but it can change forms. Law of conservation of energy initial energy = final energy Forms of Energy Chemical (bonds) Heat Work Light Sound

What does the 1st law mean for living things? Living things can not create their own energy, they must obtain it from their environment! Amount of Usable, Available Energy (chemical energy) is always decreasing in an ecosystem because it is being turned into other (unusable) forms of energy. Relate to food web/food pyramid  need more autotrophs to support a smaller number of heterotrophs Why it looks like a pyramid!

2nd Law Systems tend to change in a way that increases disorder or entropy! What does this mean for living things? Organisms must be well organized to remain alive & grow! Use energy to fight against entropy to maintain homeostasis 1-way flow of energy

Used up or Lost as heat energy Biomass – dry weight of all organic matter contained within a trophic level (grams/kg) Only about 10% of the energy stored in biomass is transferred from 1 level to the next What happens to the rest of it? Used up or Lost as heat energy

Put this information all together! Using what you have just learned, why can’t trophic levels go on forever (5,6,7th level consumers)?