Many people donât realize that chest pain and shortness of breath can be symptoms of RA. In fact, heart and lung problems can be a serious complication of the disease. People with RA have an increased incidence of blocked and hardened arteries, which could lead to heart attack or stroke, especially if they also smoke.
Calcium carbonate spicules of calcareous sponges have been found in Early Cambrian rocks from about 530 to 523 million years ago in Australia. Other probable demosponges have been found in the Early Cambrian Chengjiang fauna, from 525 to 520 million years ago. Freshwater sponges appear to be much younger, as the earliest known fossils date from the Mid-Eocene period about 48 to 40 million years ago.
1 Some species of sponges in the ocean near Antarctica are thought to be ten millennia old. 2  Specimens of the black coral genus Leiopathes are among the oldest continuously living organisms on the planet: around 4,265 years old.