| |||||||||
| |||||||||
What Are Plants?Concept Note
Plants are more complex than animals and fungi: in addition to nuclei
and mitochondria, plant cells contain plastids (organelles for tapping
the sun's energy). Plants evolved from protoctist algae that had already
incorporated cyanobacteria that became chloroplasts.
Significant challenges face the earliest plants as they confront the
demands of surviving on dry land. Accustomed to an aquatic lifestyle,
early plants lay on the surface, unable to support their weight against
gravity. Watery conjugation is no longer a viable survival strategy. The
most crucial innovation for the first true plant is the ability to develop
a fertile egg into an embryo, a multicellular young plant, within moist,
protective maternal tissue.
|
Life history of
an oak tree. Great oaks from little acorns grow. Sexual coupling
of the female and male flower (left) results in the embryo. (Illustration
by Christie Lyons)
|
|
Glossary | Home | Questions or comments, E-mail the Webmaster All contents © Foundation For Global Community |
|
