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.
Porifera: Life History and Ecology. Sponges come in an incredible variety of colors and an amazing array of shapes. They are predominantly marine, with the notable exception of the family Spongillidae, an extant group of fresh-water demosponges whose fossil record begins in the Cretaceous.Sponges are ubiquitous benthic creatures, found at all latitudes beneath the world's oceans, and from the intertidal to the deep-sea.nce the larvae are in the water column they settle and develop into juvenile sponges. Sponges that reproduce asexually produce buds or, more often, gemmules, which are packets of several cells of various types inside a protective covering. Fresh water sponges of the Spongillidae often produce gemmules prior to winter.