14.5. Patiria miniata: Bat Star http://www.ck12.org
Habitat
P. miniata’shabitat is kelp forests, rocks, tide pools, and surfgrass. It ranges from Sitka, Alaska to Baja California,
intertidal to about 950 feet below sea level.
Biology
Cell Biology
TheP. miniatahas as many as a few million eukaryotic cells. Like all other animals, these cells have many organelles,
allowing different cell types to have different functions. Organelles are structures within a cell, like the nucleus.
The nucleus is like a safe containing the factory’s trade secrets. It contains the organism’s genetic material. The
mitochondria is the powerhouse of the cell. It provides the energy needed to power chemical reactions. Vesicles are
small membrane-bound sacs that transport materials around the cell. Vacuoles are like storage centers. Lysosomes
are like recycling trucks; they carry waste. Ribosomes are non-membrane bound organelles where proteins are made.
Endoplasmic reticulum float freely in the cytoplasm. Golgi bodies work like a mail room. They receive proteins
from the rough endoplasmic reticulum and send them where they need to be. Cytoplasm helps give the cell its shape.
Cells divide when embryos are growing, when cells repair, and for making gametes. Cells come from other cells
that grow and divide. In mitosis, 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 (ex. eggs and sperm) with one half the chromosomes
(containing DNA) of the parent cell.
Evolution
P. miniatais an invertebrate, which means it does not have a backbone. This also makes it one of the earlier animals
to evolve. This animal has radial symmetry. Radial symmetry was the first type of symmetry to evolve. Organisms
that have radial symmetry have no sense of direction, making controlled movements in a certain direction impossible.
Early invertebrates didn’t have a complete digestive system; there was just one opening that serves as both its mouth
and anus. There are many important traits that have evolved in invertebrates, like multicellularity, tissues and organs.
Ecology
The Bat star starfish has a long breeding season. They can produce millions of eggs a year. The females and males
will discharge fertile sperm and eggs all year long, but more during the late spring and winter. The Bat star can live
up to thirty-five years.
The Bat star plays an important part in the ecosystem. The predators of the Bat star are crabs, seagulls, fish, sharks,
other starfish, mollusks, and crustaceans. Their prey is clams and scallops, saw well as algae, making starfish
omnivores.P. miniataeats echinoids, algae, sponges, and bryozoans. Bryozoans are tiny, aquatic animals forming
mossy colonies. The Bat star is also a scavenger, cleaning up dead animals and algae on the seafloor, making our
ocean cleaner.
Anatomy and Physiology
The Bat star can reproduce arms that have fallen off, a process known as regeneration. The mouth of the Bat star
starfish is located in the center of the stomach. When eating, starfish push their mouths outside of their body to