Lottia digitalis Point on the California coast, "L. digitalis" coexists with the similar species, "Lottia scabra", but each occupies a slightly different habitat. "L. digitalis" tends to occupy vertical rock faces or overhangs and certain horizontal ones clothed by algae and barnacles. "L. digitalis" clump together more often, prefer wave-exposed areas, occupy sites further up the shore and are seldom found in rock pools. Both species move about freely when the tide is up but "L. digitalis" settles in a different location at each low tide whereas "L. scabra" tends to home to the same spot. "L. scabra" has a more rugged
Plant physiology plants produce a vast array of chemical compounds with unique properties which they use to cope with their environment. Pigments are used by plants to absorb or detect light, and are extracted by humans for use in dyes. Other plant products may be used for the manufacture of commercially important rubber or biofuel. Perhaps the most celebrated compounds from plants are those with pharmacological activity, such as salicylic acid from which aspirin is made, morphine, and digoxin. Drug companies spend billions of dollars each year researching plant compounds for potential medicinal benefits. Plants require some nutrients, such as carbon and