The environment is much more than air, rocks and water. The
entire planet is occupied with living creatures large and small. Life is the
most important part of the environment for humans who are animals among animals.
Humans live or die depending on the stability and endurance of the biosphere. Humans derive meaning from other life forms and the smartest, kindest
humans study the biosphere , bond with and protect other animals.
Bacteria are the oldest, smallest, most adaptable life
forms on earth. They can be found everywhere from deep ocean trenches to the
uppr atmosphere and beyond. Multicellular life depends on ancient bacteria that
inhabited nucleated cells as mitochondria that supply energy to the cell. All
humans contain mitochondria inherited from their mothers. Animal life depends on oxygen supplied by plants
and single-cell phytoplankton floating in the upper levels of oceans.
An ecosystem is a community of living creatures that interact in complex ways. All ecosystems
depend on environmental resources The sun supplies the energy. Photosynthesis converts atmospheric carbon into organic molecules.
Animals feed on plants and on one another, moving life molecules and energy through the system.
Bios is life and a logos is knowledge. Biology. the study of life is now immense and complicated. Biologists
work in diverse and specialized environments. In universities, biological
disciplines are dispersed in different departments. Undergraduates take
beginners courses in biology and cannot understand the whole when they study the
parts. Students in universities may never study biology, so that “well-educated
“students are often ignorant of biological concepts and have little or no
insight into life processes. Since humans are living creatures, dependent on
living creatures, you would think that biological knowledge should come first.
What could be more important?
Ecologists who worry about human destruction of habitats
try to teach other humans about their interdependence with plants and other
animals. Non-biologists tend to exploit their home environments with little
awareness of longer term consequences.
Botanists study plants and Zoologists study animals. You
learn that plants are self-sufficient creatures who make their own food through
photosynthesis using energy provided by the sun. Animals are dependent creatures
who eat plants or eat other animals who eat plants. Humans are omnivores who eat
both plants and animals. Both plants and animals reproduce sexually with female
parts that make eggs and male parts that make sperm. Plants make seeds and
animals make eggs or give birth to live babies. Plants do not have brains, and
therefore exist without minds. Animals have brains and the degree of sentience
depends on the complexity and sophistication of the brain. Worms with little
brains are less sentient than humans with big brains. This is not to argue that
worms are less successful creatures than humans since they may still be alive
and well a 100 million years from now, and humans may disappear rather quickly.
The first living things on earth were bacteria in
the sea. They were microscopic and had tough membranes for protection. Their
descendants are still alive and well in all the oceans of planet earth. Some bacteria invented photosynthesis and gradually manufactured our
oxygen rich atmosphere. Some cells eventually became larger eukaryocytes, with
softer membranes who ate smaller cells with tough membranes. Some bacteria came
to live inside the larger cells and are now present in every animal cell as
mitochondria. Eukaryocytes joined together in clumps and eventually learned to
differentiate into specialized tissues, becoming plants and animals. Cell
clusters have differentiated into tissues that most modern animals share – skin,
nervous system, digestive system, immune system, respiratory system, circulatory
system and reproductive system.
Life is based on carbon atoms that can combine with up to 4
other atoms forming carbon bonds. Biochemistry is the study of the complex
interactions of carbon molecules that create life. A rapidly expanding field of
molecular biology reveals the chemical organization and activity within cells,
linking the genetic code with the biosynthetic pathways that are required for
cell growth, maintenance, repair and
reproduction. Organic chemistry is also the basis for
industrial manufacture of diverse materials that have become
ubiquitous on planet earth.