Download No Free Lunch

No Free Lunch
The flow of energy within closed systems and the Universe is known as thermodynamics.
The study of the flow of energy within living systems is known as ecology. The laws of
thermodynamics apply to both equally. You have learned from the first law that the
amount of energy is fixed and can be converted from one form to another. But from the
second law you learned that useable energy is always declining in the Universe and so all
matter is evolving towards a lowest possible energy state and disorder. Consider how
living things rot and become simple compounds when they die and thus evolve from a
highly ordered system to a much simpler disorderly system. Humans are animals that
survive only within a complex flow of energy that includes other living organisms and a
favorable environment that allows for the flow of energy. All organisms require a
favorable environment tuned to their needs and must work to obtain their energy.
Producers must have sunlight as well as a source of carbon and other nutrients to survive
and consumers must have access to a larger number of producers to survive. Recall the
energy pyramid and the unequal relationship of consumers to producers. All consumers
on planet Earth survive on the backs of a vast majority of producers! Note that there are
a few primitive organisms that can produce carbon based food without sunlight. These
unique organisms are found where sunlight does not penetrate and are known as
chemotrophs and are the producers of unique food pyramids at the depths of the oceans
and far below ground. Chemotrophs do however requite particular chemicals to produce
carbon based food. You may have heard the expression there is “no free lunch”. This
old saying is as true today as it ever was. It means that organisms are always working to
obtain energy and without which they die. Life is an ordered state of matter and life
fights the second law. The closest example to a free lunch on Earth is the
electromagnetic energy that comes from the Sun. Remember though that the Sun is a star
and all stars evolve to become dwarf or neutron stars or black holes and change their
energy regime as regards their surrounding planets. The important point here is that
almost all the energy on Earth ultimately derives from the Sun. The tiny bit of remaining
energy comes from the decay of radioisotopes releasing thermal energy inside the Earth.
Because the Sun literally turns a tiny amount of energy (4 million tons of matter every
second become energy in the Sun!) into a huge amount of energy which is delivered to
Earth everyday across 93 million miles of Space, and because the Sun will continue to
delver energy to Earth another 4-5 billion years this energy is as free as it gets for humans
and the vast majority of organisms occupying Earth. But recall from the second law that
energy is “lost” when sunlight is converted to other forms. In fact the majority of this
energy is “lost” as thermal energy that cannot always be used as fuel. Remember fuels
are useable forms of energy. So obtaining energy to live on Earth is work. Humans split
from chimpanzees about 6.5 million years ago and modern Homo sapiens first evolved
200,000 years old – with the great cultural leap occurring about 50,000 years ago and
modern civilization beginning at the end of the last ice age about 10,000 years ago.
Today, in the developed industrial world we work to earn tokens, money, by trading our
goods or services to obtain energy and create a suitable environment for our survival.
Since the beginning of the Industrial age, 250 years ago, we have employed chemical
energy in the form of fossil fuels to run machines and supplement the soil with nutrients
in a clever way of reducing the labor invoiced in growing our carbon based food. But for
most of our existence we have had to hunt, gather or more recently farm to obtain our
energy and necessary resources. Hunting, gathering and farming by hand is incredibly
hard work and requires a huge investment in time and energy. Remember we are
consumers and must eat a larger number of producers to sustain ourselves. In other
words, there is no free lunch for consumers – especially those at the top of the energy
pyramid. And, as we will learn, if it wasn’t for the one time gift of finite hydrocarbon
fossil fuels the majority of us would still be working today as farmers to obtain our
energy – and far fewer humans could be sustained in such a world.
Answer the questions below.
1. What is the flow of energy called? What is the study of the flow of energy in living
systems called?
2. What have we learned from the first and second law about the flow of energy in the
Universe?
3. What are chemotrophs? Where are they found?
4. What does the expression “there is no free lunch” mean?
5. Where does the vast majority of energy come from on Earth? Where does the
remaining tiny fraction of energy come from?
6. Is all the electromagnetic energy from the Sun converted to fuels on Earth? What are
fuels?
7. How old are humans? How old are Homo sapiens? How old is modern civilization?
8. How do we earn our energy today? How did humans earn their energy for most of
human existence?
9. Is hunting, gathering and farming easy work? What have human’s employed to
reduce the labor involved in growing carbon based food today?
10. What does finite mean?