Addison Art Gallery presents “Arts for the Earth,” a benefit for the Orleans Conservation Trust, on Saturday, April 24th, 10 a.m. to 5 p.m. at 43 South Orleans Road in Orleans. Maryalice Eizenberg will demonstrate oil painting from 11 a.m. to 1 p.m., Barbara Brennessel will discuss her book on diamondback terrapins from 1 to 3 p.m., and Amy Sanders will work with pastels from 3 to 4:30 p.m.