Sponges constitute the phylum Porifera, and have been defined as sessile metazoans (multicelled immobile animals) that have water intake and outlet openings connected by chambers lined with choanocytes, cells with whip-like flagella.

May 1, 2011 · All the oldest-known skeletal metazoans are interpreted as sessile benthos and are found in shallow marine carbonate settings (Table 1). They are probably of diploblast grade, i.e., stem- or crown-group cnidarians or basal stem-group bilaterians.

Mar 1, 2015 · The Agronomic Revolution (AR), spurred by increasing vertical bioturbation during the Ediacaran—Cambrian transition, permanently altered the nature of shallow marine substrate conditions and led to a major shift in adaptive strategies among benthic metazoans.

Mar 1, 2014 · Early Cambrian reef systems witnessed the rise and fall of the earliest known cryptic sessile metazoans. Subsequent Middle Cambrian to Early Ordovician microbial-dominated reefs were generally devoid of true frame-building metazoans, as well as cryptic sessile fauna.

Aug 15, 2024 · Insights into adaptations of Chengjiang sessile metazoans to the Cambrian substrate revolution. The significant changes in seafloor conditions during the Ediacaran-Cambrian transition presumably bear on the autecology of the …

Nov 29, 2020 · Throughout the Phanerozoic, sessile metazoans grew in close association with various microbial carbonates to form reefs. The first metazoans with calcareous hard-parts appeared in the terminal Ediacaran, ca 550 million years ago, and these also commonly grew associated with microbial mats, thrombolites and stromatolites, to form the oldest ...

The Agronomic Revolution (AR), spurred by increasing vertical bioturbation during the Ediacaran–Cambrian transition, permanently altered the nature of shallow marine substrate conditions and led to a major shift in adaptive strategies among benthic metazoans.

Mar 1, 2015 · These ecological and evolutionary changes, known as the Cambrian Substrate Revolution (CSR), are generally understood from observations of benthic metazoans across the Ediacaran–Cambrian...

May 8, 2017 · Here, we review the results of these investigations and discuss their implications for understanding the earliest stages of animal evolution, including the origin of metazoan genes and genome...

Oct 2, 2024 · This type of symmetry is common in Cnidarians, such as jellyfish and hydras, and is adapted to sessile or slow-moving lifestyles. A modified form, pentamerous symmetry , is found in organisms like starfish, which can be divided into five symmetrical parts along specific planes.