Transcript Part 1: Foundations of Environmental Science Ch 4 From Chemistry to Energy to Life PowerPoint® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2006 Pearson.

Part 1: Foundations of
Environmental Science
Ch 4
From Chemistry to
Energy to Life
PowerPoint® Slides prepared by
Jay Withgott and Heidi Marcum
Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
This lecture will help you understand:
• The fundamentals of
chemistry
• The molecular building
blocks of organisms: cell
• Energy and energy flow
• Photosynthesis, respiration,
and chemosynthesis
• Major hypotheses for life’s
origins
• Our knowledge of early life
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Exxon Valdez Oil Tanker
In Prince William Sound, Alaska
Central Case: Bioremediation of the Exxon Valdez Oil Spill
• In 1989, 11 M gallons coated the Alaskan
coastline
The largest spill in U.S. history
• Defiled the pristine environment
• Tourism plummeted and jobs were lost
• Bioremediation: pollution cleanup
through enhanced natural
biodegradation
Some soil bacteria or fungi degrade Oil
CmHn → C2H5OH + CO2 + H2O
The recent BP Gulf Oil Spill (April ~ June, 2010):
~ 0.5 M gallons/day → ca. 50M gal , as of June 6, 2010.
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Chemistry is crucial for understanding:
• How gases contribute to global
climate change
• How pollutants cause acid rain
• The effects on health of wildlife
and people
• Water pollution
• Wastewater treatment
• Atmospheric ozone depletion
• Energy issues
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Chemical building blocks
• Matter : all material in the universe that has mass and
occupies space
- Can be transformed from one type of substance into
others
- But it cannot be destroyed or created which is…
“The Law of Conservation of Matter”
- the amount of matter stays constant
- It is recycled in nutrient cycles and ecosystems
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Chemical building blocks
• Matter :
Mass
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Volume
Chemical building blocks
• Element : a fundamental type of matter, with a given set
of properties (Table 4.1: Abundance)
- Atoms : the smallest components that maintain an
element’s chemical properties (J. Dalton, ~1805)
Divisible ?
- The atom’s nucleus has protons (positively charged
particles) and neutrons (particles lacking electric
charge)
- Atomic number: the defined number of protons
- Electrons : negatively charged particles surrounding
the nucleus
- Balances the positively charged protons
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The structure of an atom
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Chemical building blocks
• Isotopes : atoms with
differing numbers of neutrons
- Mass number : the
combined number of
protons and neutrons
- Isotopes of an element
behave differently
- Some isotopes are
radioactive and decay
until they become nonradioactive stable
isotopes
- Emit high-energy
radiation
6th Mtg end (9/4/08)
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Radioactive decay (Natural Disintegration of R. Isotopes)
very useful in dating materials
• Half-life (t1/2) : the amount of time it takes for one-half of the
atoms to disintegrate giving off radiation
- Different radio-isotopes have different half-lives (ms~Gyrs)
Short (Human) history
14C
→
14N
(5,730 y), organic matter (wood)
Very Long (Geological) History
238U
→
206Pb
(4.47Gy), inorganic (rocks)
235U
→
207Pb
(0.704Gy), inorganic (rocks)
230Th
→
226Ra
(25ky), inorganic (oceanic sediment)
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7th Mtg starts (9/9/08)
Natural Disintegrations of Radiosotpopes (cont’d)
The major source of geothermal energy (γ-ray)
40K
→
238U
→ → → 226Ra →
222Rn
235U
→ → → 223Ra →
219Rn
→→→
207Pb
(0.704 Gy)
232Th
→ → → 224Ra → 220Rn → → →
208Pb
(14 Gy)
40Ar
(1.28 Gy)
→ → → 206Pb (4.47G y)
Artificial Disintegrations (“forced”)
235U
+ n → 91Kr + 142Ba +3n
- Atomic Bomb (forced, uncontrolled)
- Nuclear Power Plant (forced, controlled)
Added(8/22/2013)
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7th Mtg starts (9/9/08)
Molecules & Compounds
Molecules : Combinations of two or more atoms
Oxygen gas (O2), Water(H2O), Sucrose (C12 H22O11)
Compounds : A molecule composed of atoms of two or
more different elements
- Water : two hydrogen atoms bonded to one oxygen
atom: H2O
- Carbon dioxide : one carbon atom with two oxygen
atoms: CO2
6th Mtg end (9/4/08)
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Ions:
eleectrically charged particles
• Atoms (electrically neutral) may gain or lose electrons
to become ions
→ electrically charged.
• If loses e- → Cations (+) : Na+, Mg2+
• If gains e- →Anions (-):
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Cl-, O2-
Atoms are held together with bonds
• Covalent bond : atoms in a molecule share electrons
- For example, the atoms that bond to form CH4.
• Polar covalent bonds : Atoms share electrons unequally,
with one atom exerting a greater pull
The oxygen in a water molecule attracts electrons: H2O
• Ionic bonds : an electron is transferred from one atom to
another
- Are not molecules, but are salts, such as table salt,
NaCl
• Solutions : mixture of substances w/o chemical bonding,
eg.: wine, coca cola, oil, blood
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Water: the main reason life can exist
• Hydrogen bond : oxygen
from one water molecule
attracts hydrogen atoms of
another
• Water’s strong cohesion allows
nutrients and waste to be
transported
FOUR fellow neighbors for
every water molecules in ice
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• Water absorbs heat with only
small changes in its
temperature, which stabilizes
systems
Additional properties of water
• Less dense ice floats on liquid water (Why less dense? )
• Water dissolves other molecules (excellent solvent)
Density = mass/volume ,
d=m/V
Dependence of density on temperature causes:
→weather, wind, ocean currents, plate tectonics
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Water ionizes: H2O → H++ OH-
Concentrations of H+ determine
acidity of solutions
• The pH scale ranges from 0 to 14
and quantifies the acidity of
solutions: pH= -log[H+]
- Acidic solutions: pH < 7
- Basic solutions:
pH > 7
- Neutral solutions: pH = 7
[H+] = [OH-] = 10-7 M
• A substance with pH of 6 contains
10 times as many H+ as a substance
with pH of 7
7th Mtg end (9/9/08)
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Drain Cleaner
Organic Compounds
• Organic Compounds : carbon atoms joined by covalent
bonds and may include other elements
- Such as nitrogen, oxygen, sulfur, and phosphorus
• Hydrocarbons : contain only carbon and hydrogen
- The simplest hydrocarbon is methane
- Hydrocarbons can be a gas, liquid or solid
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Macromolecules: The building blocks of life
large-size molecules
often Polymers : long chains of repeated molecules
- Three types of polymers are essential to life
- Proteins
- Nucleic acids
- Carbohydrates
- Lipids (are not polymers, but are also essential)
→ forms polymer like assembly
water insoluble
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Proteins
• Produce tissues, provide structural support, store & transport energy
- Animals use proteins to generate skin, hair, muscles, and tendons
- Some function as components of the immune system
- They can serve as enzymes, molecules that promote certain
chemical reactions
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A special process involving proteins
• Deoxyribonucleic acid (DNA) and Ribonucleic Acid
(RNA) carry the hereditary information of organisms
• - Long chains of nucleotides that contain
sugar, phosphate, and a nitrogen base
• Information in DNA is rewritten to RNA
• RNA directs amino acid assembly into
proteins that are synthesized (Ribosome)
• Genes : regions of DNA that code for
proteins that perform certain functions
contained in Chromosomes.
• Chromsome: made of DNA & Proteins
coiled compact form of Chromatin
• Genome: A complete set of chromosomes
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Carbohydrates and Lipids
• Carbohydrates : consist of atoms of carbon, hydrogen, and
oxygen (C, H & O)
- Sugars : carbohydrate
Glucose : provides energy for cells
- Complex carbohydrates build structures and store energy
(Natural Polymer)
Starch : a complex carbohydrate of plant
Cellulose: plant cell wall
Glycogen: a complex carbohydrate of plant
• Lipids : a chemically diverse group of compounds grouped
together because they don’t dissolve in water
cell membranes, structural support, and steroids
• Lignin: Second most abundant macromolecule in plant (-> humic)
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We create synthetic polymers
• Plastics : synthetic (human-made) polymers
- Best known by their brand names (Nylon, Teflon, Kevlar)
- Many are derived from petroleum hydrocarbons
- Valuable because they resist chemical breakdown
- Problematic because they cause long-lasting waste and
pollution
- Wildlife and health problems, water quality issues,
harmful to marine animals
- We must design less-polluting alternatives and
increase recycling
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Organization of matter in living things
• Cell : the basic unit of life’s organization
• Prokaryotes : single-celled organisms
lacking organelles and a nucleus
• Eukaryotes : organisms containing
complex cells with internal structures
(organelles with membrane)
Protists, Plants, Fungi, Animals
- Ribosomes synthesize proteins
- Mitrochondria extract energy from
sugars and fats
- Nucleus houses DNA
- Chloroplast: Photosynthesis
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Hierarchy of matter
in organisms
Matter is
organized in a
hierarchy of
levels, from
atoms through
cells through
organ systems
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Characteristics of Living Organism (“Life”):
(1) Organization: ordered
(2) Exchange matter and energy with surroundings
(environments)
- consume matter & energy to maintain (& move)
(3) Response to stimuli
(4) Reproduction
(5) Evolution: Undergo change to adapt to new
environments which is changing all the time.
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Universe: consists of Matter and Energy
“Law of Conservation of Mass & Energy”
• Matter:
Non-Living Matters: Inorganic
Living Matters (Organism): “Life” (Organic)
• Energy:
Electromagnetic Energy(Light)
Potential E., Kinetic E., Chemical E.
• Living Organisms exchanges matter and energy with
surroundings (environments)
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Energy fundamentals
• Energy : that which can change the position, physical composition
or temperature of matter – ability to do a work (= Force x Distance)
Potential energy (PE): energy of position
Kinetic energy (KE): energy of motion
Chemical energy (CE): potential energy held in the bonds
• PE is changed into KE to produce motion, action, and heat
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Energy is conserved...but changes in quality
• First law of thermodynamics = energy can change forms, but
cannot be created or destroyed
• Second law of thermodynamics = the nature of energy
changes from a more-ordered to a less-ordered state
- Entropy = an increasing state of disorder
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The sun’s energy powers life
• The sun releases radiation of the electromagnetic wave
- Some is visible light,
E= h (=hc/)
- h=6.626x10-34 J.s (Planck’s constant),  = frequency
• Solar energy drives weather and climate, and powers plant growth
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Photosynthesis
• Autotrophs (primary
producers) : organisms
such as green plants, algae
and cyanobacteria produce
their own food from the
sun’s energy
• Photosynthesis : the
process of turning light
energy from the sun into
chemical energy
- Carbon dioxide + water
+ sun’s energy is
converted into sugars
and high-quality energy
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Photosynthesis produces food (sugar)
• Chloroplasts : organelles where photosynthesis occurs
- Contain chlorophyll : a light-absorbing pigment
- Light reaction : splits water by using solar energy
- Calvin cycle : links carbon atoms from carbon dioxide
into sugar (glucose)
6CO2 + 6H2O + sun light(energy) → C6H12O6 + 6O2
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Cellular respiration releases chemical energy
• Organisms use chemical
energy from photosynthesis
• Oxygen is used to convert
glucose into water + carbon
dioxide + energy
• Heterotrophs: organisms
that gain energy by feeding
on others
- Animals, fungi, many
microbes
C6H12O6 + 6O2
→
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6CO2 + 6H2O + Energy
Early Earth:a very different place (Fig. 4.21, Tree of Life)
• 4.5 billion years ago, Earth was a hostile place
- Severe volcanic and tectonic activity
- No oxygen (O2) existed in the atmosphere, until
photosynthesis developed in microbes in a later stage
CO2, CO, NH3, CH4, OH2, H2, Ar, He
Escape Velocity: 12km/sec
- Intense ultraviolet energy from the sun reaches Earth
(b/c no O3 layer formed in the upper atmosphere)
- No life existed
• Life was only possible
in the deep bottom of
ocean, where sun’s
radiation can’t reach
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Several hypotheses explain life’s origin
• Primordial Soup (the Heterotrophic Hypothesis):
life originated from a “primordial soup” of simple
inorganic chemicals in the oceans
- First life forms used organic compounds for energy
• Life from the Depths (the Chemoautotrophic
Hypothesis): life originated in deep-sea hydrothermal
vents, with abundant sulfur
- First organisms were chemoautrotrophs
• “Seeds” from Space (the Panspermia Hypothesis):
microbes from space traveled on meteorites to Earth
- Cosmic Ansestory, Exogenesis
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Geothermal energy powers Earth’s systems
• Hydrothermal vents: black smoker: underwater mini-volcano
host entire communities that thrive in high temperature and pressure
- Lack of sun prevents photosynthesis
- Chemosynthesis: uses energy in hydrogen sulfide to produce
sugar
6CO2 + 6H2O + 3H2S
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C6H12O6 + 3H2SO4
Early Life:
It’s the fossil record that teaches about earlier life
on earth and its history
• Single-celled bacteria occurred on
Earth ~ 4 billion years ago
Eukaryotes ~ 2 billion years
• Fossil: an imprint in stone of a dead
organism
• Fossil record : gives information
about the history of past life
• Trilobites: Cambrian ~ Permian Period (540-250 M years ago):
Extinct, probably with a Volcanic Eruption;
• Dinosaurs: Triassic ~ Cretaceous Period (250~65 Mya)
Extinct with an Asteroid Impact
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Brief history of Life on Earth: time before present (BP)
4.6G BP, Earth formed (CO2, CO, CH4, NH3, OH2, H2)
4.3~3.8G BP, Age of Bombardment, Chemical Evolution
3.8G BP, First Prokaryote (Archeo-Bacteria): Chemosynthetic Autotrophs
3.5G BP, Blue-green Algae, (O2 ~ 0.2%)
: Photosynthetic Autotrophs
3.2G BP, Photosynthetic Bacteria produce O2, but used up
2.1G BP, First Eukaryotes, O2 started to buildup
1.5G BP, Multicellular organism (O2 ~ 3%)
800-550M BP, Cryogenic Era (-40oC): Snow Ball Earth
544M BP, Large, complex organisms (Cambrian Period starts: Explosion)
505M BP, Fish
Paleozoic Era (540~251M, ~ Permian P.)
480M BP, Land plants
400M BP, Insects
380M BP, Amphibians
330M BP, Reptiles, Birds
Mesozoic(251~65M, Triassic ~ CretaceousP.)
220M BP, Mammals
Cenozoic (65M~ )
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40M
BP,
Primates
5M BP, Hominids
2M BP, Homo
Brief history of Mammals on Earth:
544M BP, Large, complex organisms (Cambrian Period starts)
505M BP, Fish
Paleozoic (540~251M)
480M BP, Land plants
Age of Fishes
400M BP, Insects
380M BP, Amphibians
330M BP, Reptiles, Birds
220M BP, Mammals
50M BP, Primates
5M BP, Hominids
Mesozoic(251~65M)
(Other Classes: Reptila, Amphibia)
(Other Orders: Carnivora, Insectivora)
(Other Families: Lemur, Monkeys)
Age of Reptiles
Cenozoic (65M~)
Age of Mammals
2M BP, Genus Homo diverged from Australopithecines
(Homo Hablis started to use Stone Tool)
.25M BP, Homo Sapiens evolved replacing H. Erectus & H. Neanderthalensis
(in Asia)
(in Europe)
0.05M BP, culture develop more rapidly
0.01M BP, Neolithic Age (Domestication of Animals, Plants), First Town
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0.005
M BP, History started
The fossil record shows that…
• Earlier organisms evolved into later ones
• Numbers of species increase over time in general
• The vast majority of species are extinct
• Earlier organisms were smaller and simpler
• Several mass extinctions have occurred at every 50~150
M yrs, 5 major ones during last 500 M yrs
• Large, complex organisms occurred 600 M years ago
(since Cambrian Period) ~ 4G yrs after Earth formed.
Early periods (87% of Earth Life) hade been rather
quiet with extremely sluggish development of life forms
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TREE of LIFE:
Present-day organisms help
decipher history
Biologists use
present-day organisms
to get information
about evolution
The tree of life now
consists of 3 prongs:
bacteria, archaea,
eukaryotes (Domains)
Archea: single-celled
prokaryotes very
different from
bacteria
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Tree of Life:
Bacteria:
large group of unicellular, prokaryote, microorganisms
a few micrometres in length, shapes of spheres to rods & spirals.
40 million bacterial cells in a gram of soil and a million bacteria cells
in a millilitre of fresh water; five nonillion (5×1030) on Earth.
Protist: eg., Protozoa, protophita, slime mold, water mold.
Eucaryote - Unicellular or Multicellular w/o specialized tissues
Fungi:
eg., Yeast, Mold, Mushroom
Hetrotrophic organisms
with chitinous (N-acetylglucosamine) cell wall
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Conclusion
• Life on Earth has flourished for over 3 billion years
• Deciphering life’s origins depends on understanding
- Energy
- Energy flow
- Chemistry
• Chemistry can also help find solutions to environmental
problems
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QUESTION: Review
Which of the following part of an atom has a
negative charge?
a) Proton
b) Neutron
c) Electron
d) Hydrogen
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QUESTION: Review
Ionic bonds are bonds that ……
a) Share electrons
b) Occur when an electron is transferred from
one atom to another
c) Share electrons unequally
d) Lose an electron
Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
QUESTION: Review
Which of the following is NOT a reason water is
essential for life?
a) Water can absorb large amounts of heat
without changing temperature
b) Waste and nutrients can be transported in
water
c) Ice floats on liquid water, so fish survive cold
winters
d) Water usually cannot dissolve other
molecules
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QUESTION: Review
Of the following macromolecules, which one is
NOT a polymer?
a) Lipids
b) Proteins
c) Carbohydrates
d) Nucleic acids
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QUESTION: Review
Sugars, starches, and glucose are all:
a) Lipids
b) Proteins
c) Carbohydrates
d) Nucleic acids
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QUESTION: Review
According to the second law of thermodynamics …?
a) Energy cannot be created or destroyed
b) Things tend to move toward a more disorderly state
c) Matter can be created, but not energy
d) Kinetic energy is the most efficient source of energy
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QUESTION: Review
Which of the following organisms is an autotroph?
a) Deep-sea tubeworm
b) Horse
c) Pine tree
d) None of these
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QUESTION: Weighing the Issues
Which hypothesis do you believe best explains the origin of
life on Earth?
a) The heterotrophic hypothesis (primordial soup)
b) The panspermia hypothesis (“seeds” from space)
c) The chemoautotrophic hypothesis (life from the
ocean depths)
d) None of these; life did not evolve
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QUESTION: Interpreting Graphs and Data
A molecule of the hydrocarbon ethane contains…?
a) 10 carbon atoms and 8
hydrogen atoms
b) 8 carbon molecules and 10
hydrogen enzymes
c) Carbon and hydrogen DNA
d) Two different ions
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QUESTION: Interpreting Graphs and Data
Which is the most acidic
material?
a) Soft soap
b) Rainwater
c) Acid rain
d) Lemon juice
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