A Chautauqua County senior services organization is continuing its evolution, adding memory care services at its Gerry campus, a new home care division as well as expanded contract management services for other retirement communities in Erie County and beyond. Heritage Ministries, based in Jamestown, filed plans this week with the state Department of Health to create a secure Alzheimer's dementia unit in the north wing of Heritage Village Rehab and Skilled Nursing, its 120-bed skilled nursing…