Lecture 3

Lecture 3Environmental Systems:

Chemistry, Energy, and Ecosystems

What will I learn today?1. Learn why chemistry is important in environmental

biology

2. See chemistry applied to real-world situations

3. Learn the building blocks of living organisms

4. Understand the types of energy and the basis energy flow in the Universe

5. Distinguish the different ways of making and using energy.

6. Learn about the origin of life on Earth

7. What do we understand about early life

Application of chemistry and biology to real world issues

• Two great case studies…

Exxon Valdez

Case study 1

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Exxon Valdez oil tanker in Prince William Sound, Alaska

Oil Tanker

Disaster• On March 24, 1989• Alaska’s Prince William Sound • Tanker Exxon Valdez struck a reef• Spilled 42 million L (11 million gal) of crude oil• This oil eventually coated 2,100 km (1,300 mi) of

Alaskan coastline. • The largest oil spill in U.S. history

– it killed an estimated – 100,000-400,000 seabirds, – 2,600-5,500 sea otters,– 200-300 harbor seals, and countless fish.



Wild life was dying - The feathers of birds do not insulate when covered in oil. The birds were dying of hypothermia

Clean up effort - classical• The cleanup crews corralled the oil with

– booms– skimmed it from the water– soaked it up with absorbent materials– and dispersed it with chemicals. – They pressure-washed the beaches, removed

contaminated sand with backhoes and tractors, – and even tried burning the oil.

• It simply was too slow or not working



Then TV crews say scientists spraying fertilizer!!!!!

Clean up effort - Biological• Scientists tested a new cleanup strategy• One that enlisted nature to help take care of the mess.

– They stimulated naturally occurring bacteria to biodegrade, or break down, the oil.

– About 5% of the natural bacteria present on Alaskan beaches feed on chemical compounds called hydrocarbons that are produced by conifer trees.

• Hydrocarbons from conifers are chemically similar to the hydrocarbons that make up crude oil, so scientists predicted that the microbes might also be able to degrade oil.

– Scientists from the EPA and Exxon decided to put the bacteria to work in a process called bioremediation

• DEF - the attempt to clean up pollution by enhancing natural processes of biodegradation by living organisms.

http://www.youtube.com/watch?v=sboyx3sKsWw&feature=related

Bioremediation• It worked on the test beaches • It was applied to all the areas suitable

• Some say it helped…• Others say that it did little• In general it did aid in removing the oil• Now common for scientists and companies to

offer a custom solution to a problem.

Dead Zone

Case study 2

Gulf of Mexico

• Each year in the spring and summer the ocean waters of the coast of Louisiana and troubled!!!

http://www.smm.org/deadzone/

• Watch this flash interactive lesson.

Bioremediation

• Scientists have discovered that certain plants, bacteria, and animals have special systems that can be used

• Consider…

Plants used as filters• When soil is contaminated with heavy metals

from mining, manufacturing, or other causes, the standard solution has been to dig up tons of soil and pile it into a hazardous waste dump.

• As an alternative, scientists are developing methods of phytoremediation, using plants to detoxify contaminated soils.



Toxic Selenium• Most heavy metals are

toxic to plants, just as they are to wildlife and people.

• But some plants can take up toxic elements and store them without harm.

• The researchers concluded that the reed was most effective at removing selenium.



Chemistry

• Atoms and elements are chemical building blocks

• Lets see how much we know?



FACTS

Each Group

Take a minute and come up with a skit about how an atom is organized

Each Group

Take a minute and come up with a skit explaining what an isotope is.



Isotopes

Isotopes and radiodating

Atoms bond to form molecules and compounds

• Take a minute and come up with a skit explaining the difference between molecules and compounds

The chemical structure of the water molecule facilitates life

• Take a minute and come up with a list of features of water that make it very different from other compounds

Water

• Hydrogen bonding

• Freezing point

• Boiling point

• Density

• Specific heat capacity

pH

• Take a moment and come up with a good definition of what the pH scale measures and give good examples of each.

Hydrogen ions determine pH



Matter is composed of organic and inorganic compounds

• What is organic and what is inorganic?

• Carbon atoms (and hydrogen) = organic

• Mix in some N, O, S, P

• Inorganic molecules lack C-C bonds

Macromolecules are building blocks of life

• What is a macromolecule?

• Very long!– Proteins– Carbohydrates– DNA & RNA

We create synthetic polymers

• Give examples of synthetic polymers?

• What are some of the issues with these synthetic polymers?

Organisms use cells to compartmentalize macromolecules

• Isolation

• Protection



Hierarchy of order

Energy Fundamentals

Energy is always conserved . .

. . . But energy changes in quality

Light energy from the sun powers most living systems



Photosynthesis produces food for plants and animals

Cellular respiration releases chemical energy

Geothermal energy also powers Earth’s systems

The Origin of Life

How life originated is one of the most centrally important, and

intensely debated, questions in modern science.

Early Earth was a very different place



Early Earth was a very different place

• Earth formed about 4.5 billion years ago

• For several hundred million years Earth was hostile– UV light– Volcanic activity– Lava– Comets

Several hypotheses have been proposed to explain life’s origin

• Three prominent theories follow…

• Listen and see which one do you relate to most?

Primordial soup: The heterotrophic hypothesis

• life originated from a ‘primordial soup’ of simple inorganic chemicals dissolved in the ocean’s surface waters or tidal shallows.

• Lab experiments have provided evidence that such a process can work.– 1953 Miller and Urey made simple organic

molecules in a test tube!

“Seeds” from space:The panspermia hypothesis

• Microbes from elsewhere in the solar system traveled on meteorites that crashed to Earth.

• The Murchison meteorite, which fell in Australia in 1969, was found to contain many amino acids, suggesting that amino acids within rock can survive impact.

Life from the depths: The chemoautotrophic hypothesis

• Life originated at deep-sea hydrothermal vents, where sulfur was abundant.

• The first organisms were chemoautotrophs, creating their own food from hydrogen sulfide.

• Genetic analysis of the relationships of present-day organisms suggests that some of the most ancient ancestors of today’s life forms lived in extremely hot, wet environments.

Questions for thought!• Which lines of evidence in the debate

over the origin of life strike you as the most convincing, and why?

• Which strike you as the least convincing, and why?

• Can you think of any further scientific research that could be done to address the question of how life originated?

The fossil record has taught us much about life’s history

• Fossils

• Radioactive dating

• Similarity in structure

• Developmental plans

• DNA comparisons

• Protein comparisons



Present-day organisms and their genes help us decipher life’s history

• Compare as many genes of living organisms

• Enter into a computer and ask it to determine how related they are.

• Supports the fossil evidence

• Supports the other evidence too!



Latest thinking on the origin of life based on huge amounts of data. New data keeps on supporting this theory.

THEORY - don’t get the wrong notion about this word!

Just a theory.

Conclusions•Chemistry can also be a tool for finding solutions to environmental problems.

•Cleaning up chemical pollution through bioremediation with microbes or plants is just one example.

•Chemistry can be a powerful ally, whether one wants to analyze agricultural practices, manage water resources, reform energy policy, conduct toxicological studies, or find ways to mitigate global climate change.

•Remember your chemistry forever

Lecture 3

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