Essay Title: 

human ecology

April 2, 2016 | Author: | Posted in health and medicine


Sea Stars : Keystone Species

Keystone species is a species whose very presence contributes to a diversity of life and whose extinction would consequently lead to the extinction of other forms of life . It helps support the ecosystem of which they are a part (Keystone Species , n .d . In our marine ecosystem , sea stars or starfish , are considered as keystone species

Sea stars are sea creatures that falls under Phylum Echinodermata and are the main predators of mussels . This animal is usually found on the middle [banner_entry_middle]

intertidal wherein the organisms are often submerged and uncovered by the tides on a regular basis . On the other hand , mussels are dominant competitors for space on many rocky shores . Their upper limit is set by dessiccation and filtering time , while their lower limit is by predatory sea stars (Castro and Hubder , 1997 . Sea stars set the limit where the mussels thrive by preying on it

The primary food of sea stars is mussels . Sea stars and other mussel predators have strong effect on the ecosystem . They venture into the mussel bed during high tide and eat some of the mussels before retreating with the tide . In this manner , the sea stars , opens up space for other organisms such as acorn barnacles , gooseneck barnacles and seaweeds . Sea stars also thrive on dog whelks which are predators of barnacles . In so doing , the barnacles are given by the sea stars higher survival rate by reducing the number of dog whelks (Castro and Huber 1997

Marine biologist describes sea stars are keystone predators because much of the structure of the community they are living in depends on them . If sea stars are removed in the middle intertidal area , mussels are able to live and cover other areas in the ecosystem . Thus , mussels would be able to monopolize the available space by growing and crowding out other species (Castro and Huber , 1997

It should be noted however , that many intertidal species are more abundant than the sea stars , but the sea stars are of central importance to the community . Removing the sea stars in the system would greatly affect the ecosystem and the organisms thriving in it (Castro and Huber 1997 . References

Castro , Peter and Huber , Michael (1997 . Marine Biology 2nd Edition United States of America . Times Mirror Higher Education Group , Inc 2460 Keeper Boulevard , Dubuque , IA 52001

Keystone Species . n .d . Keystone Species . Retrived on 17 January 2007 from HYPERLINK “http /www .prairiedogs .org /keystone .html http /www .prairiedogs .org /keystone .html




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