Porifera
Introduction:
Porifera contain the sponges: the most ancient of all animal groups. They originated in the Cambrian period around 600 million years ago. They have a simple structure, with no tissue or organs, instead made up of different cells with individual functions.
All sponges are sessile: meaning they live permanently attached to rocks and other substrates, they cannot move around on their own.
They live in aquatic habitats, with the majority occupying marine environments although some species live in freshwater lakes and streams. They occupy a range of depths from the shallow coasts to trenches in seas, up to 5km deep.
Their forms differ depending on the environment they habit, in deeper areas they tend to be larger e.g. the giant barrel sponge
In the museum sponges can be found in outer cabinet 1
Structure and adaptations:
Sponges are considered simple due to the lack of complex tissues and organs, this doesn't mean they are not well adapted. In fact sponges are considered one of the most successful animal groups precisely because of their simple design which has remained relatively unchanged since their initial evolution.
They receive food, nutrients and oxygen from the water surrounding them.
Make-up of a sponge:
The sponge consists of a central cavity, large opening (osculum) and smaller openings (ostia). It is built from specialist cells with different features:
The 'skin' of the sponge (pinacoderms)
Cells with tentacle-like-structures to draw water inside (choanocytes)
Digestive cells (amoebocytes). These can move, even crawling to the outside of the sponge to clean it!
Structural cells that make up the body (spicules)
Classification:
There are 4 distinct classes of sponges distinguished by their material structure
Calcarea
Calcerous sponges
Hexactinellida
The glass sponges
Demospongiae
The most diverse. Containing 90% of all living sponges
Homoscleromorpha
Simplest structure, smallest group
Explore the Porifera in greater detail using One Zoom:
Museum highlights:
Venus' flower basket sponge: these glass sponges are regarded as symbols of eternal love as they often contain a pair of mated shrimp living inside. Their intricate lattice structure inspired buildings like the Gherkin in London.
Spongia officinalis- a variety of bath sponge that has been harvested throughout history for human use from washing, padding in helmets, absorbent materials in surgeries and many other applications.
Breadcrumb sponge, which gets its name from it's crumbly texture when picked up, despite having a smooth texture when attached to rock. They also produce a strong smell (similar to exploded gunpowder) to deter predators
Specimen Gallery:
(c) NOAA Photo Library: reef3860, image licensed under the Creative Commons Attribution 2.0 Generic License Sponge diagram: Amsel, Sheri. "Phylum - Porifera (Sponges)" Exploring Nature Educational Resource ©2005-2024. Accessed November 16, 2023, < http://www.exploringnature.org/db/view/Porifera-Sponges >Calcareous sponge: Clathrina clathrus (Schmidt, 1864) et Hemimycale columella (Bowerbank, 1874).jpg, Parent Gery - Own work, Public Domain, https://en.wikipedia.org/wiki/Calcareous_sponge#/media/File:Clathrina_clathrus_(Schmidt,_1864)_et_Hemimycale_columella_(Bowerbank,_1874).jpg Demonspongia: Callyspongia plicifera (Azure Vase Sponge).jpg, Nhobgood,- Own work, Public Domain, https://en.m.wikipedia.org/wiki/File:Callyspongia_plicifera_(Azure_vase_sponge).jpg Homoscleromorpha sponges: By Géry PARENT - Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=10460076