1. Environmental Systems
Chapter 2 – Module 4

2. Mono Lake Terminal Lake (water flows in, but it doesn’t flow out)
Alkaline – water picks up salts and minerals and deposits them in lake
Mono brine shrimp and Mono Lake alkali fly support migrating birds (sandpipers, gulls and flycatchers)

3. Mono Lake
1913 – City of Los Angeles plans to redirect water away from Mono and Owen’s Lake
Owen’s Lake redirected first, dried up, by 1930 it was an empty salt flat
One of the nation’s largest sources of windblown dust – dust contains arsenic
1941 – start to redirect water away from Mono Lake
By 1981 – depths decreased by half, salinity increased to more than twice that of the ocean
Salinity killed algae, shrimp died due to lack of food, birds stayed away or were preyed upon by coyotes

4. Mono Lake
1994 – Audubon Society and environmentalists convinced the LA Dept of Water and Power to reduce the amount of water it diverted
2009 – water levels just short of 2/3 of its historic depth
2013 – brine shrimp are thriving and birds are returning.
City of LA had to reduce water consumption
Converted grass lawns to drought-tolerant native shrubs
Low flow showerheads and toilets
This is an example of the interconnectedness of humans and biotic and abiotic factors in the environment
A change in one factor often has unexpected effects.

5. What is a system?
Set of interacting components that influence one another by exchanging energy or materials.
A change in one part of the system affects one or more other parts of the system
Natural systems – set of interactions between living organisms, nonliving matter and energy

6. Matter Matter is anything that has mass and takes up space
Mass – the amount of matter an object contains
Weight – the force that results from gravity acting on mass. You would weigh less on the moon because gravity is weaker there, but you would have the same mass.
Atom – is the basic unit of matter

7. Element
A substance consisting of atoms with the same number of protons.
94 naturally occurring elements, 24 man-made
Molecule – particles that contain more than one atom
Compound – molecules that contain more than one element

8. Atomic Structure Atomic number = # of protons
Mass number = total# of protons and neutrons
Isotope = atoms of the same element with different # of neutrons
Electron = negatively charged particle orbiting nucleus
Proton = positively charged particle in nucleus
Neutron = neutral particle in nucleus

9. Radioactivity
Unstable isotopes spontaneously undergo radioactive decay – release material from the nucleus and may emit harmful radiation
Half-life – the time it takes for one half of the radioactive atoms to decay
Used to determine the length of time that a radioactive element is dangerous
Carbon dating can be used to determine how long ago an organism died.

10. Chemical Bonds
To form molecules or compounds, atoms must be held together by bonds
Covalent Bonds – electrons are shared
Ionic Bonds – electrons are transferred creating positively and negatively charged ions. The ions attract to form the bond.
Hydrogen Bonds – unequal sharing of electrons creates partial charges. The attraction between partially charged molecules creates hydrogen bonds.

11. Covalent Bond

12. Ionic Bond

13. Water
Polar molecule – unequal sharing of electrons creates partial charges
Hydrogen bonds form between water molecules
Gives water many unique properties
Density
Cohesion & Adhesion
Capillary Action
High Specific Heat – put a lot of energy in to change its temperature
Universal Solvent

14. pH – the relative strength of acids and bases
Basic or alkaline
pH>7
Acid – substance that dissociates into hydrogen ions (H+) and a negative ion in solution
Base – substance that forms hydroxide ions (OH-) and a positive ion in solution
Water is Neutral H+=OH-
Acidic
pH<7

15. Chemical Reactions
The separation of atoms from molecules or the recombination of atoms with other molecules
Bonds between atoms change

16. Conservation of Matter
The law of conservation of matter:
Matter can neither be created or destroyed; it can only change form.
Let’s prove this to be true. In a group you will design an experiment that will demonstrate the law of conservation of matter. You must write a lab write up for your experiment.

17. Biological Molecules
Organic chemistry – based on carbon to carbon and carbon to hydrogen bonds
Inorganic chemistry – do not contain carbon or carbon is bound to elements other than hydrogen (Carbon dioxide)

18. Biological Molecules Basis of Life
Carbohydrates – sugars
Main energy source of living things
Proteins
Structural, energy storage, transport, part of immune system
Nucleic Acids – DNA and RNA
Genetic information
Lipids – fats, waxes, and steroids.
Cell membranes and some hormones

19. Cells The smallest structural and functional component of organisms.
All living things are made of cells.

20. Energy, Flows and Feedbacks
Chapter 2 – Module 5

21. Energy Energy The ability to do work or transfer heat.
The basic unit of energy is the Joule
The amount of energy used when a 1-watt electrical device is turned on for 1 second.
Power The rate at which work is done.
energy = power × time unit kWh – energy use
power = energy ÷ time unit kW – turbine’s power
Joule - kg⋅m2⋅s−2

22. Energy Conversions

23. Different Types of Energy
There are different forms of energy and they can be converted from one form to another.
Potential – stored energy, ex water in a dam
Chemical – potential energy stored in bonds
Nuclear
Thermal
Kinetic – energy of motion
Electrical
Mechanical
Electromagnetic – visible light, uv, infrared, microwaves, x-rays
Sound

24. Electromagnetic Spectrum
The longer the wavelength, the lower the energy

25. All matter contains some energy
Temperature is the measure of the average kinetic energy of a substance.
Changes in temperature can convert matter from one state to another.

26. The Laws of Thermodynamics
First Law of Thermodynamics: Energy is neither created nor destroyed, but it can change from one form to another.

27. The Laws of Thermodynamics
Second Law of Thermodynamics: When energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes.

28. The Laws of Thermodynamics
Second Law of Thermodynamics: When energy is transformed, the quantity of energy remains the same, but its ability to do work diminishes. All systems move towards increased entropy.
Energy Efficiency - the ratio of the amount of energy in the desired form to the total amount of initial energy
To calculate, multiply all individual efficiencies
Energy Quality – based on how easily an energy source can be used for work
Gasoline is a higher quality energy source compared to wood
Entropy – disorder or randomness in a system. As energy loses its ability to do work, entropy increases.

29. Open and Closed Systems
Open – exchanges matter and energy with other systems
Closed – no exchange of matter and energy with other systems

30. Steady State A system in steady state. Inputs = Outputs
System doesn’t change over time.

31. Negative and Positive Feedback
Feedbacks are found throughout the environment.
Triggered by a change in the environment
Negative feedback loop A feedback loop in which a system responds to a change by returning to its original state, or by decreasing the rate at which the change is occurring. Reverses the change.
Positive feedback loop A feedback loop in which change in a system is amplified, taken further from original state. Enhances the change.

32. Examples of Feedback Loops

33. Examples of Feedback Loops
Change: Warmer temperatures on Earth Result: Increased evaporation of water Negative Feedback – low altitude clouds reflect sunlight back into space = less heating of surface, less evaporation, less warming Positive Feedback – high altitude clouds absorb additional energy = more heating of surface, more evaporation, more warming