1. Chapter 3: Earth’s Environmental Systems

2. Section 1: Matter and the Environment

3. Building Blocks of Chemistry
All material in the universe that has mass and occupies space is called matter
Atoms and elements are the building blocks of chemistry
Atoms are the basic units of matter
Every atom has a nucleus that contains protons (positive charge) and neutrons (neutral charge)
Electrons (negative charge) surround the nucleus

4. An element is a chemical substance with a given set of properties that cannot be broken down into substances with other properties
The atoms of each element have a defined number of protons: atomic number.

5. Carbon, nitrogen, hydrogen, and oxygen are elements especially abundant in living things
When atoms combine, it is called bonding
When atoms share electrons, they generate a covalent bond
When electrons are transferred from one atom to another it forms an ionic bond

6. A molecule is a combination of two or more atoms of the same type or different types joined by covalent bonds.
A substance composed of atoms of two or more different elements is called a compound.

7. Inorganic compounds lack carbon-to-carbon bonds
Living things are made up of organic compounds, and they produce organic compounds.
Organic compounds consist of carbon atoms (and usually hydrogen atoms) joined by covalent bonds.
Carbon’s unusual ability to build complex and elaborate molecules results in millions of different organic compounds
Inorganic compounds lack carbon-to-carbon bonds

8. Hydrocarbons are organic compounds containing only hydrogen and carbon
Some hydrocarbons and products of their burning are hazardous
Polycyclic aromatic hydrocarbons (PAHs) can evaporate from spilled or incompletely burned oil and gasoline and can mix with water
Toxic to aquatic animals and some have been shown to cause cancer in people
Some can cause smog when exposed to sunlight

9. A mixture in which all the ingredients are evenly distributed is called a solution.
Liquids, gasses, or solids

10. Macromolecules
Proteins, nucleic acids, carbohydrates, and lipids are the building blocks of life.
Macromolecules are large organic molecules, including proteins, nucleic acids, carbohydrates, and lipids.

11. Proteins are polymers that serve many functions in organisms; they are organic compounds made up of carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur.
Polymers are long chains of repeated molecules

12. Some help produce tissues and provide support
Some store energy, transport substances, or work within the immune system
Some act as hormones – molecules that serve as chemical messengers within an organism
Some serve as enzymes – molecules that promote certain chemical reactions

13. Nucleic acids are macromolecules that direct protein production
Made up of chains of nucleotides – sugar molecule, phosphate group, and nitrogen base.
DNA carries hereditary information and is responsible for passing traits from parent to offspring
Genes are the parts of the DNA that order the production of certain proteins
In most organisms, the set of all of an individual’s genes is divided into chromosomes
RNA are copies of DNA segments that are involved in making proteins

14. Carbohydrates are polymers that consist of atoms of carbon, hydrogen, and oxygen.
A simple carbohydrate (or sugar) has three to seven carbon atoms and a formula that is some multiple of CH2O.
Ex: glucose = C6H12O6

15. Glucose is one of the most common and important sugars
Provides energy that fuels plants and animal cells
Building blocks for complex carbohydrates, such as starch
The structures that support the bodies of most plants and animals contain complex carbohydrates

16. Lipids are a chemically diverse group of macromolecules that are classified together because they do not dissolve in water.
Made up of carbon, hydrogen, oxygen, and sometimes phosphorous
Common lipids = fats, oils, phospholipids, waxes, and steroids

17. Water
Water is a unique compound with several unusual properties that make it essential to life.
Covers more than 70% of the Earth’s surface
A water molecule’s oxygen atom attracts electrons more strongly than its two hydrogen atoms, resulting in a polar molecule with a partial negative charge at the oxygen end and a partially positive charge at the hydrogen end.

18. The oxygen atom of one molecule is weakly attracted to one or two hydrogen atoms of another in a hydrogen bond
Cohesion is the molecular force between water molecules that holds them together, making water stick to itself.
Results in a high surface tension of water which allows some insects to walk on water.

19. Heating weakens the hydrogen bonds in water, but it does not initially increase the molecular motion, which is what causes temperature to rise – water can absorb a large amount of energy with only small changes in temperature: high specific heat.
Helps stabilize aquatic environments

20. Ice is less dense than liquid water – reverse pattern of most other compounds
Floating ice insulates bodies of water, preventing them from freezing solid in the winter

21. Water is often called the “universal solvent”
Water molecules bond well with other polar molecules
The positive end of one molecule bonds with the negative end of another molecule
Can dissolve many other molecules

22. Each separation results in:
In any water solution, a small number of water molecules separate into ions – charged atoms.
Each separation results in:
A hydrogen ion (H+)
A hydroxide ion (OH-)

23. Pure water contain equal amounts of these ions: neutral pH
Solutions that have a higher H+ concentration are considered acidic
Solutions that have a higher OH- concentration are considered basic, or alkaline

24. The pH scale describes the acidity or alkalinity of a solution and runs from 0-14
7 = neutral
> 7 = basic
< 7 = acidic
Each point on the scale represents a tenfold difference in hydrogen ion concentration

25. Section 2: Systems in Environmental Science

26. Interacting System
An output of one of Earth’s systems is often also an input to that or another system
Systems seldom have well-defined boundaries, so deciding where one system ends and another begins can be difficult
Systems may exchange energy, matter, and information with other systems, and they may contain or be contained within other systems
The boundaries we draw for a system usually depend on our focus at the moment

27. Inputs into Earth’s systems include energy, information, and matter
A feedback loop is a circular process that describes how an event is both a cause and an effect in the same system; can be a positive feedback loop or a negative feedback loop.

28. In a negative feedback loop, the output of a system moving in one direction acts as input causes the system to move in the other direction
Input and output respond to each other’s effects, canceling them out and stabilizing the system
Ex: thermostat

29. Positive feedback loops have the opposite effect of negative feedback loops.
Rather than stabilizing a system, they drive it toward an extreme
Ex: erosion – the removal of soil by water, wind, ice, or gravity

30. Earth’s “Spheres”
Earth’s geosphere, lithosphere, biosphere, atmosphere, and hydrosphere are defined according to their functions in Earth’s systems
Earth’s geosphere is made up of all the rock at and below Earth’s surface
The lithosphere is the hard rock on and just below earth’s surface – the outermost layer of the geosphere.

31. The biosphere consists of all the planet’s living or once-living things and the nonliving parts of the environment with which they interact.
The atmosphere consists of the layers of gases surrounding our planet.
The hydrosphere encompasses all water – salt, fresh, liquid, ice, and vapor – on Earth’s surface, underground, and in the atmosphere.

32. Section 3: Earth’s Sphere’s

33. The Geosphere
Earth’s geosphere consists of the crust, the mantle, and the core
Earth’s crust is a thin layer of relatively cool rock that forms Earth’s outer skin both on dry land and in the ocean
Below the crust us the mantle, a layer of very hot but mostly solid rock

34. Beneath the lower mantle is Earth’s core
Outer core is made up of molten metals such as iron and nickel
Inner core is a dense ball of solid metal

35. These plates move about 2-15 centimeters per year
Plate tectonics
As the asthenosphere moves, it drags along large plates of lithosphere called tectonic plates.
Earth’s surface consists of about 15 major tectonic plates
These plates move about 2-15 centimeters per year

36. Collisions and separations of plates result in landforms – mountains, islands, and continents
Landforms influence climate, which affects rates of soil formation, erosion, and deposition, which determine which organisms inhabit a region.

37. At divergent plate boundaries, magma surges upward to the surface and pushes past plates apart, creating new crust as it cools
When two plates meet, they may slip and grind alongside one another, forming a transform plate boundary
Friction between plates often spawns earthquakes

38. One plate may slide beneath another in a process called subduction
When plates collide at convergent plate boundaries, one of two events happens
One plate may slide beneath another in a process called subduction
The subducted crust is heated by the mantle and may send up magma that erupts through the surface in volcanoes
The two plates may collide, slowly lifting material from both plates in a process called mountain-building

39. The Biosphere and Atmosphere
Earth’s biosphere and atmosphere are the living Earth and the ocean of gases that supports and protects it
The part of Earth in which living things interact with nonliving things is Earth’s biosphere

40. The atmosphere contains the gases that organisms use for their life processes.
A layer of ozone (gas molecule made up of 3 oxygen atoms) protects the biosphere from the sun’s radiation
Keeps Earth warm enough to support life – greenhouse effect

41. The Hydrosphere
Water cycles through the lithosphere, biosphere, and atmosphere
Most of Earth’s water is salt water, 97.5%, only 2.5% of Earth’s water is fresh water
More than three quarters of fresh water is ice
Only about 0.5% of Earth’s water is usable for humans

42. The water cycle, or hydrologic cycle, summarizes the roles that water – liquid, gaseous, and solid – plays in our environment
Evaporation is the conversion of a substance from a liquid to a gas
Transpiration is the release of water vapor by plants through their leaves

43. Human activity can affect every aspect of the water cycle
Water returns from the atmosphere to Earth’s surface as precipitation such as rain or snow
Occurs when water vapor undergoes condensation
Much flows as runoff into bodies of surface water such as rivers, lakes, and oceans
Some precipitation and surface water soaks down through soil and rock to recharge underground reservoirs, or storage areas, known as aquifers – layers of rock and soil that hold groundwater
Fresh water found underground
Human activity can affect every aspect of the water cycle

44. Section 4: Biogeochemical Cycles

45. Nutrient Cycling Nutrients cycle through the environment endlessly
The law of conservation of matter states that matter may be transformed from one type to another, but cannot be created or destroyed.
Explains why the amount of matter in the environment stays the same as it flows through matter cycles

46. Nutrients are matter that organisms require for their life processes.
Nutrients circulate endlessly throughout the environment in complex cycles called biogeochemical cycles, or nutrient cycles.
Carbon, oxygen, phosphorus, and nitrogen are nutrients that cycle through all of Earth’s spheres and organisms

47. The Carbon Cycle
Producers play vital roles in the cycling of carbon through the environment
Primary producers are organisms that produce their own food
In photosynthesis, producers pull carbon dioxide out of their environment and combine it with water in the presence of sunlight
6CO2 + 6H2O + the sun’s energy  C6H12O6 (glucose) + 6O2

48. Consumers are organisms, mainly animals, that must eat other organisms to obtain nutrients
Decomposers are organisms such as bacteria and fungi that break down wastes and dead organisms

49. Reverse of photosynthesis
Cellular respiration is the process by which organisms use oxygen to release the chemical energy of sugars and release carbon dioxide and water
Not breathing
Reverse of photosynthesis
C6H12O6 (glucose) + 6O2  6CO2 + 6H2O + energy

50. Organisms do not release all the carbon they take in, some use it for their life processes.
When organisms die in water, their remains may settle in sediments, which accumulate, increasing pressure on earlier layers which can convert soft tissues into fossil fuels, and shells and skeletons into sedimentary rock such as limestone.
Releases some of its carbon through erosion and volcanic eruptions

51. The oceans are the second-largest carbon reservoir as they absorb carbon compounds from the atmosphere, runoff, undersea volcanoes, and wastes and remains of organisms.
Humans shift carbon to the atmosphere in many ways – extracting fossil fuels, burning fossil fuels, and cutting down forests.
Scientists have long been baffled by a missing carbon sink – a reservoir of a substance that accepts more of that substance than it releases

53. The Phosphorus Cycle
The phosphorous cycle keeps phosphorus availability naturally low
Involves mainly the lithosphere and the oceans
The amount of phosphorus in organisms is dwarfed by the vast amounts in rocks, soil, sediments, and the oceans

54. Plants can take up phosphorus through their roots only when it is dissolved in water
Consumers acquire phosphorus from the water they drink and the organisms they eat

55. Human impacts
Mine phosphorus to use as fertilizer
Release phosphorus-rich wastewater containing detergents and fertilizers
The addition of phosphorus to bodies of water can lead to an overgrowth of producers in a process called eutrophication

57. The Nitrogen Cycle
The nitrogen cycle relies on bacteria that make nitrogen useful to organisms and bacteria that can return it to the atmosphere
Nitrogen makes up 78% of our atmosphere by mass, and is the sixth most abundant element

58. Nitrogen gas cannot cycle out of the atmosphere and into organisms, naturally scarce
Once nitrogen undergoes the right kind of chemical change – assisted by lightning, specialized bacteria, or human technology – it becomes usable to the organisms that need it.
Nitrogen fixation is the conversion of nitrogen gas into ammonia
In the process of nitrification, ammonium ions are first converted into nitrite ions, then into nitrate ions

59. Denitrifying bacteria convert nitrates in soil or water back to nitrogen gas
The Haber-Bosch process enabled people to produce ammonia on a large scale
When we burn fossil fuels we increase the rate at which nitric oxide enters the atmosphere and reacts to form nitrogen dioxide which can lead to acid precipitation.