Upload
cornelia-mcdonald
View
221
Download
1
Embed Size (px)
Citation preview
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Matter, Energy, and Life
Chapter 3
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
BASICS
• Matter - Everything that has mass and takes up space. Solid - Liquid - Gas
• Elements - Substances that cannot be broken down into simpler forms by ordinary chemical reactions. Periodic Table
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Basics Atoms - Smallest particles exhibiting
characteristics of the element.- Protons - Neutrons - Electrons- Atomic Number: # Protons- Isotope - Forms of an element differing
in atomic mass. (Different # of neutrons)
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Basics
Molecule: Two or more atoms joined together.
- Compound: Two or more different types of atoms joined together.
Chemical Bond - Forces (chemical energy) holding atoms together in molecules.
- Covalent - Sharing of electrons- Ionic - Cations and Anions - Hydrogen - Unequal attraction of shared
electrons: Water
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Molecules and Compounds
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Ions, Acids, and Bases
• Ions - Atoms that contain more or fewer electrons than protons.
• Acids - Substances that release Hydrogen ions.
• Bases - Substances that readily bond with Hydrogen ions. pH Scale: 0-14
- < 7 Acidic- > 7 Basic
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Organic Compounds
• Organic Compounds - Material making up biomolecules. Formed by rings and chains of Carbon. Four major categories:
- Lipids- Carbohydrates- Proteins- Nucleic Acids
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cells
• Cells - Minute compartments in a living organism which carry out process of life. Surrounded by lipid membrane controlling
flow of materials in and out of cell. Interior sub-divided into organelles and
sub-atomic particles.• Enzymes - Class of proteins - molecular
catalysts regulating chemical reactions.• Metabolism - Multitude of enzymatic
reactions performed by an organism.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
ENERGY
• Energy - Ability to do work. Kinetic - Energy in moving objects. Potential - Stored energy.
- Chemical - Stored in food or fossil fuels.• Power - Rate of doing work.• Heat - Total kinetic energy in a substance not
associated with bulk motion.• Temperature - Measure of speed of motion of
atoms in a molecule.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Thermodynamics
• Energy must be supplied from an external source to keep biological processes running. Energy flows in a one-way path through
living systems and into a temperature sink.• First Law of Thermodynamics - Energy is
neither created nor destroyed.• Second Law of Thermodynamics - With each
successive energy transfer, less energy is available to perform work. Entropy
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
ENERGY FOR LIFE
• Ultimately, most organisms depend on the sun for energy needed to carry out life processes.
• Solar energy is essential for (2) reasons: Warmth Photosynthesis
- Radiant energy transformed into useful, high-quality chemical energy in the bonds of organic molecules.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Energy For Life
• Of all solar radiation reaching the earth’s surface, about 10% is Ultraviolet, 45% is Visible, and 45% is Infrared. Most of energy is absorbed by land or
water, or reflected back into space.- Only about 1-2% of the sunlight falling
on plants is captured for photosynthesis.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Electromagnetic Spectrum
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Photosynthesis
• Occurs in membranous organelles of green plant cells called chloroplasts.
• 6H20+6CO2 + solar energy = C6H12O6+6O2
• Water and carbon dioxide in the presence of sunlight yields glucose (sugar) and oxygen.
• Glucose serves as primary fuel for all metabolic processes in plant cells.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Respiration
• Photosynthesis captures energy, while cellular respiration releases energy. Cellular respiration splits carbon and
hydrogen atoms from the sugar molecule and recombine them with oxygen to re-create carbon dioxide and water.
• C6H12O6 + 6O2 = 6H2O +6CO2 + energy
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
SPECIES TO ECOSYSTEMS
• Population - All members of a species living in a given area at the same time.
• Community - All of the populations of organisms living and interacting in a particular area.
• Ecosystem - Biological community and its physical environment. Somewhat user-defined Open or closed boundaries
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Food Chains
• Photosynthesis is described as Primary Productivity because it is the basis for almost all other growth in an ecosystem. Manufacture of biomass by organisms
eating plants is termed Secondary Productivity.
• Food Chain - Linked feeding series. Food Web - Most consumers have multiple
food sources.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Trophic Levels
• Trophic Level - Expression of an organism’s feeding status in an ecosystem. Producers (plants) Consumers
- Primary, Secondary, Tertiary Most terrestrial food chains relatively short. Aquatic food chains tend to be longer.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Trophic Levels
• Organisms can also be identified by the type of food they consume: Herbivores (Plants) {Deer} Carnivores (Meat) {Wolves} Omnivores (Plants/Meat) {Bears} Scavengers (Carcasses) {Crows} Detritivores (Debris) {Ants} Decomposers (All) {Bacteria}
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Ecological Pyramids
• Due to Second Law of Thermodynamics, food chains often form an inverted pyramid. Metabolism Predator efficiency < 100% 10% Rule (Energy / Biomass)
- 100 kg clover 10 kg rabbits
1 kg foxes
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
MATERIAL CYCLES
• Carbon Cycle Begins with intake of CO2 during
photosynthesis. Carbon atoms are incorporated into glucose and then:
- Remain in plant material until death. Eaten by predator Respiration Excretion Incorporation
Death (Decomposers)
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Carbon Cycle
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Nitrogen Cycle
• Plants uptake inorganic nitrogen from the environment and build protein molecules which are later eaten by consumers. Nitrogen-fixing bacteria change nitrogen to
a less mobile, more useful form by combining it with hydrogen to make ammonia - used to build amino acids.
- Members of bean family (legumes) have nitrogen-fixing bacteria living in their root tissue.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Nitrogen Cycle
Nitrogen re-enters the environment:- Death of organisms- Excrement and urinary wastes
Nitrogen re-enters atmosphere when denitrifying bacteria break down nitrates into N2 and nitrous oxide (N2O)gases.
- Humans have profoundly altered nitrogen cycle via use of synthetic fertilizers, nitrogen-fixing crops, and burning fossil fuels.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Nitrogen Cycle
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Phosphorous Cycle
• Phosphorous compounds are leached from rocks and minerals and usually transported in aqueous form. Taken in and incorporated by producers.
- Passed on to consumers. Returned to environment by
decomposition.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Phosphorous Cycle
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.
Sulfur Cycle
• Most sulfur tied up in underground rocks and minerals. Inorganic sulfur released into air by weathering and volcanic eruptions. Cycle is complicated by large number of
oxidation states the element can assume. Human activities release large amounts of
sulfur, primarily by burning fossil fuels.- Important determinant in rainfall acidity.
Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.