Nutrition
There are two basic ways by which an organism can
build up its body: by heterotrophy or by autotrophy.
In heterotrophy, the creature captures and consumes
living or dead organic matter, as we do ourselves. In
autotrophy, the organism synthesizes organic matter
from inorganic CO2, for example, by utilizing the
effect of sunlight in the presence of chlorophylllike
pigments, a process known as photosynthesis.
Quite a number of microfossil groups employ these
two strategies together and are therefore known as
mixotrophic.
Reproduction
Asexual (or vegetative) and sexual reproduction are
the two basic modes of cellular increase. The simple
division of the cell found in asexual reproduction
results in the production of two or more daughter cells
with nuclear contents similar in proportion to those of
the parent. In sexual reproduction, the aim is to halve
these normal nuclear proportions so that sexual fusion
with another ‘halved’ cell can eventually take place.
Information contained in each cell can then be passed
around to the advantage of the species. This halving
process is achieved by a fourfold division of the cell,
called meiosis, which results in four daughter cells
rather than two.