10.1. Encelia californica: Bush Sunflower http://www.ck12.org
Biology
Cell Biology
Encelia californica, like all other plants, has eukaryotic cells. The difference between eukaryotes and prokaryotes
is that eukaryotes have cells with a nucleus and many organelles. TheEncelia californicacells have the following
cell parts: a nucleus, which is similar to a safe that contains the factories trade secrets, a cytoskeleton, part of the
cytoplasm that gives the cell its shape, ribosomes, the non-membrane bound organelles where all the proteins are
made, and vacuoles, which act like a storage center. Unlike animal cells, plants have organelles called chloroplasts
that allow the plant to make its own food using sunlight. Encelia californicacells divide in two different ways,
through mitosis and through meiosis. Mitosis is when the nucleus divides, and each new cell contains a copy of the
DNA in the original cell. Meiosis is when the cell divides to produce gametes with one half of the chromosomes
(containing DNA) of the parent cells.Encelia californicaneeds gametes for reproduction.
Genetics
Evolution
Flowers have existed for nearly 140 million years. They have thrived and adapted in their need to survive. They first
adapted to become land plants with spores. Spores first were aquatic and adapted to land. Later plants had evolved
to produce seeds but had not yet grown flowers. Later when the plants started to first develop flowers, plants thrived,
spreading flowers and fruits everywhere. Seeds are spread everywhere by the way of the fruits.
Ecology
The large, bright yellow sunflowers attract a variety of pollinators including bees, flies, and butterflies. These
pollinators usually tend to stay put for a good amount of time, in order to drink the nectar or collect all the pollen.
Fruits serve as a carrier for the seeds to continue reproduction of theE. californica.
Anatomy, Morphology and Physiology
Encelia californicatends to bloom in the late winter/early spring, mid spring, and in the late spring/early summer.
The flowering process first begins when the pollen from a flower’s anther is transferred to the stigma. There are two
types of fertilization- cross-fertilization and self-fertilization. Self fertilization is when the pollen from one flower’s
anther is transferred to the same flower’s eggs. Cross fertilization is when a flower’s pollen is transferred to an
entirely different plant’s stigma.E. californicacan most likely be fertilized only through cross pollination. When
the eggs become fertilized, they evolve into seeds. When the petals of a flower fall off only to leave the ovary, they
will soon develop into the flowering plant’s fruit.Encelia californicais a dicot. Dicots are plants with seeds that
sprout two leaves when they germinate.
E. californicaand members of its plant family are unique in many different ways. They have flower heads which
look like single flowers, but are clusters of individual flowers. These individual flowers can be disk flowers that are
located in the center part or ray flowers that look like petals. Most sunflower species have both disk and ray flowers,
but some just have disk flowers, and some just have ray flowers.E. californicahas both: the brown in the middle are
disk flowers, and the yellow on the outside are ray flowers.