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Characteristics
Lifestyles
Environmental Conditions
Adaptations
Interactions
100
This organism is a filter feeder. Name it and name the phylum and class
Mytilus californicus Phylum: Mollusca Class: Bivavlvia
100
The Pisaster ochraceus lives in these inter-tidal zones
low and middle intertidal zones
100
Why does the P. ochraceus feed mainly in the summer?
because the food is more abundant during that season and less abundant in the winter
100
What is the function of the pyloric caeca in P. ochraceus?
It provides a place to store nutrients, and has adapted to grow during the summer seasons when food is more abundant in order to store nutrients for the winter.
100
Which parasitic species relatively newly discovered in the Pacific infects the testes of the P. ochraceus?
Orchitophrya stellarum
200
The two organisms that share the same phylum and class and the name of the phylum and class.
Pisaster ochraceus, Leptasterias hexactis Phylum: Echinodermata Class: Asteroidea
200
This organism feeds mainly in the summer time.
Pisaster ochraceus
200
The intertidal plankton bloom generally occurs in the springtime. Why is this important to the spawning of the P. ochraceus?
Spring is the opportune time for P. ochraceus to spawn. One major reason for this is that the plankton bloom creates an increase in food sources for the new P. ochraceus larvae to feed.
200
These adaptations allow Mytilus californicus to attach to hard surfaces on boulders and rocks and move across the rocks' surfaces.
byssus threads
200
The preferred food of Pisaster ochraceus and the main reason why P. ochraceus is considered a "keystone species".
Mytilus californicus
300
The aboral surface of this organism is usually dark green or indigo.
Leptesterias hexactis
300
One reason why the Leptesterias hexactis is unusual in its reproductive methods
it broods its eggs and young.
300
Environmental reasons why some organisms, such as sea stars and starfish, live in low and mid-intertidal zones.
they need to be washed with salt water at least twice a day or they will dry up
300
What is the purpose for the Leptesterias hexactis' especially long, strong arms.
to obtain its food by breaking open mollusk shells, and to help it attach to the rough and rocky surfaces of rocks that it lives under
300
Ingesting these protists (1) can cause these organisms to become poisonous due to the dinoflagellates's ingested poison (1). Name both.
1)dinoflagellates 2) Mytilus californicus
400
This organism has a pyloric caeca.
Pisaster ochraceus
400
The significance of the spawning cycle pattern of the Mytilus californicus and what those spawning cycles are.
allows for the species to develop into large crowded colonies and spawn more during months when P. ochraceus and L. hexactis are not releasing young, therefore, the year-long spawning "cycle" helps them avoid getting eaten to extinction by the echinoderms.
400
How are gonads and the pyloric caeca adapted to maximize the environmental resources in different seasons?
In the winter, the gonads use nutrients stored in the pyloric caeca to grow in preparation for gamete creation and spawning during the spring. The pyloric caeca collect nutrients during the spring because that is when food sources are most plentiful.
400
Describe the function/evolutionary significance of the growth pattern of the pyloric caeca in P. ochraceus
The pyloric caeca grows in the summer and early fall because food is most abundant then. It serves as food storage space and allows P. ochraceus to take up as many nutrients as possible during this season. In the winter, it shrinks by allowing the gonads to use the stored nutrients for gonad growth in preparation for mating season.
400
Leptasterias hexactis is a major competitor for food for P. ochraceus. Explain why this is significant in terms of spawning seasons for the organisms. Hint: The two species spawn at opposite times of the year.
Since the two species are competitors for the same food, it benefits them to spawn at opposite times of year to reduce competition for their new larval offspring, and increase their survival rate.
500
What is the difference in spine structure between P. ochraceus and L. hexactis
P. ochraceus have ossicles arranged in a pentagon around the central disk. L. hexactis have flattened spines.
500
Out of the three species discussed which one(s) are predators and name one example their food source.
P. ochraceus and L. hexactis
500
M. californicus generally lives in the upper intertidal zone. What environmental conditions in terms of (1) salinity (2) water levels exist in this zone that the M. californicus requires to be successful?
1) high salinity 2) low water level
500
Why does P. ochraceus need skin that is not very permeable to water compared to other species of starfish?
because they eat other organisms (such as mussels that live in the upeer tidal zone) that live in tidal zones with less water , so they must be able to withstand dry conditions without becoming quickly dehydrated
500
Describe the relationship between the three species discussed: 1) P. ochraceus 2) L. hexactis 3) M. californicus
P. ochraceus and L. hexactis are similar in nature, and are competitors for food, such as mussels, barnacles, chitons, limpets, etc. They both prey on M. californicus, a type of mussel.