Prokaryotes are single-celled organisms that do not have a
membrane-bound nucleus. They live in nearly every environment
on Earth. Many live in places where no other organisms can live,
such as scalding hot water and inside solid rock. Prokaryotes are a
major source of food for many organisms. They also help many
organisms, including humans, cattle, and insects, digest food.
Prokaryotes also play an important role as decomposers of dead
organic matter in the environment.
Even though most prokaryotes are tiny organisms, they differ
greatly in their genetic traits, in their sources of energy and
nutrients, and in their habitats. Through DNA technology, scientist
Carl Woese and his colleagues found in the late 1970s that
there are two major branches, or domains, of prokaryotes. One
branch, formerly called Eubacteria (YOO-bak-TIR-ee-uh), is called
Bacteria. The other branch is called Archaea (ahr-KEE-uh), formerly
called Archaebacteria. The name archaea means “archaic” or
“ancient.” Most known species of archaea live in extreme environments
thought to resemble harsh environments present millions
of years ago.
membrane-bound nucleus. They live in nearly every environment
on Earth. Many live in places where no other organisms can live,
such as scalding hot water and inside solid rock. Prokaryotes are a
major source of food for many organisms. They also help many
organisms, including humans, cattle, and insects, digest food.
Prokaryotes also play an important role as decomposers of dead
organic matter in the environment.
Even though most prokaryotes are tiny organisms, they differ
greatly in their genetic traits, in their sources of energy and
nutrients, and in their habitats. Through DNA technology, scientist
Carl Woese and his colleagues found in the late 1970s that
there are two major branches, or domains, of prokaryotes. One
branch, formerly called Eubacteria (YOO-bak-TIR-ee-uh), is called
Bacteria. The other branch is called Archaea (ahr-KEE-uh), formerly
called Archaebacteria. The name archaea means “archaic” or
“ancient.” Most known species of archaea live in extreme environments
thought to resemble harsh environments present millions
of years ago.
