EVERYDAY SCIENCE

Detailed explanation-1: -Recent genomic studies have suggested that comb jellies, members of the phylum Ctenophora, are the sister group to all animals but now new research, led by the University of Bristol, reaffirms the traditional view – that sponges (Porifera) are the oldest animal phylum.

Detailed explanation-2: -Scientists debate when sponges, animals belonging to the phylum Porifera, first emerged. Some think it wasn’t until the Cambrian period, between 541 million and 485 million years ago, whereas others put it as early as 760 million years ago, during Precambrian times.

Detailed explanation-3: -Relatives of the humble sea sponge have filtered Earth’s waters for hundreds of millions of years or more, long before the first plants took to land. Their simplicity has led scientists to suggest sponges were the earliest animals to arise on our planet.

Detailed explanation-4: -Poriferan apomorphies Sponges were first recognised unequivocally as being animals by Ellis (1755), Pallas (1766) and Ellis & Solander (1786), although an acrimonious debate on this topic continued for at least a century (see Lévi, 1999).

Detailed explanation-5: -Members of the phylum Porifera emerged during the Precambrian, 700 million years ago (Müller, 1997). Sponges are represented in all seas and oceans of the world and are able to resist extreme climatic modifications such as glaciation (Figure 1; Wang et al., 2010).