"Pollination" is really a type of formal
definition referring to the process of delivering
a male gametophyte (pollen grain) to the
female gamete (egg). Formally, pollination
is the transfer of a pollen grain from an anther
to a stigma (in flowering plants -- the
angiosperms) or to the area of the ovule in more
primitive, non-flowering plants (the gymnosperms,
such as ferns).
"Fertilization" refers (usually) to the
actual fusion of the male gamete with the
I bet you can figure out your second question
on your own, just be breaking it down into its
parts. External refers to "outside the body" and
you already know what "fertilization" refers to.
So... "external fertilization" means that
the gametes (sperm and egg) are released
externally and the fusion to form the new embryo
occurs externally (outside of the mother's body).
This often is referred to as a "spawn."
Most marine invertebrates use this method as well,
as do many freshwater species of animals. Contrast
this with "internal fertilization," which
is the method used by most mammals. Think about
the different "challenges" that external
fertilization/spawning poses as compared to
internal fertilization. For example, an external
fertilizing situation poses problems with dilution
(how does the sperm find the egg?) and with
avoiding being eaten by other animals while an
internal fertilizer has different challenges.
Can you think of "strategies" used by the
animals that help overcome these challenges?
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