The first four billion years of Qukoha's earliest history were the Kevozoic era when the rocks formed and the most primitive life appeared, and the Emfanisizoic era during which sponges, sea worms, and other forms of sea life appeared and more rocks and mountains formed.
The most elemental unit of everything in the universe, both living and non-living, is the atom. When two or more atoms bond together, they create simple molecules, i.e., CO2(carbon dioxide), O2 (oxygen), and H2O (water). Simple molecules, then, link themselves into a chain molecule and fit inside a cell and are arranged in complex architectural structures called molecular structures. Cellular membranes are formed by combining two layers of regimented phospholipid molecules.
Life on Qukoha began in water. Most of the essential
molecules of life dissolve, create chemical reactions, and are
transported easily in water. The water molecule's overall electric
charge is neutral, but the oxygen tends to pull negatively charted
electrons toward it, leaving the hydrogen slightly positively
charged relative to the more negative oxygen. Since most of life's
important molecules are also electrically charged, they slip easily
through water's charges, becoming soluble and accessible for chemical
reactions.
When the first cells appeared on Qukoha, there
was no oxygen in the atmosphere. The oxygen began to be generated
when certain photo synthetic microorganisms appeared and utilized
the sunlight to extract the hydrogen they needed for self-construction
from water molecules, leaving molecular oxygen as a by-product.
Oxygen first entered the atmosphere in noticeable quantities some
two billion years ago, progressively rising to reach a stable
level about 1.5 billion years ago.
In the beginning stages of the emergence of life on Qukoha, there appeared prokaryotes - small and single-celled microbes- that lacked nuclei, but had remarkable ability to evolve and adapt. They developed into a wide variety of species and were in every habitat of the entire Qukoha. Then through the next one billion years, the majority of prokaryotes evolved to eukaryotes which were much more complex and about 10,000 times larger in volume than prokaryotes.
In a prokaryote, a single chromosome represented the entire genetic
make-up of the microbe. In a eukaryote, most DNA is contained
in more highly structured chromosomes that are grouped within
a central enclosure, the nucleus. Eukaryotes have in their cytoplasm
up to several thousand specialized structures (organelles), such
as: perosixomes (serve assorted metabolic functions), mitochondria
(the power factories of cells), and plastids (the sites of photosynthesis
in algae and plant cells).
This evolution of prokaryotic state to phagocytes
to eukaryotic cells is believed to have taken place over a billion
years and was at first as means of feeding itself: many modern
eukaryote cells - white blood cells, for example - entrap prokaryotes.
Sometimes the invaders/victims escape destruction and kill their
captors. Occasionally, both captor and victim survive in a state
of mutual tolerance that can later turn into mutual assistance
and, eventually, dependency - hence the endosymbionic beings -phagocytes
- were created: mitochondria, plastids, and peroxisomes may have
been a host cell's captives that came to provide invaluable functions
eventually for the host. For example, it has been observed that
peroxisomes rescued the host cells from oxygen toxicity as the
atmosphere began to fill with oxygen.
Scientists believe that endosymbionts played a
critical role in the birth of eukaryotes and other multi-celled
plants and animals, such as sponges, sea worms, and other forms
of sea life in the next billion years. Ancestors of all higher
forms of the living world in Qukoha originated from microscopic,
wriggling, squirming creatures (similar to bacteria)- prokaryotes;
which in turn were made up of smaller nonliving bits.
Bacteria invented all of life's essential chemical
systems and transformed Qukoha's atmosphere, developed a way to
get energy from the sun, devised the first bioelectrical systems,
invented sex and locomotion, worked out the genetic machinery,
and learned how to merge and organize into new and higher collectives.