Porifera diversity and placozoa Flashcards
What are the 5 major animal groups?
- Bilateria (~25 phyla)
- Porifera
- placozoa
- Cnidaria
- Ctenophora
What is the central space within a sponge, where water collects?
Spongocoel
What are the three sponge body plans, from least to most complex?
- Asconoid
- syconoid
- leuconoid
What are the main threats to sponge survival?
- predation
- competition with other sponges
- fouling/sedimentation
Many sponge species reproduce sexually, as they are _______ _____________. Sponges are also _______ meaning they are male first.
Many sponge species reproduce sexually, as they are SEQUENTIAL HERMAPHRODITES. Sponges are also PROTANDROUS, meaning they are male first.
How do sponges reproduce asexually?
- fragmentation
- releasing gemmules
What are gemmules?
- structures made by freshwater sponges, primarily a mechanism to survive hard conditions, similar to a seed
- when conditions are less harsh, archaeocyte mass on the inside will release
What are the four classes of sponges?
- calcarea
- demospongiae
- hexactinellida
- homoscleromorpha
What are two main points on the calcarea class?
- spicules are made of CaCO3
- this class contains all three body parts
What are three points about the demospongiae class?
- ~80% of sponges
- only have the leuconoid body plan
- spongin are made of silica spicules, but the spicules are never CaCO3
What is the main identifying factor of Hexactinellida class sponges?
- their body plans are not made of individual cells, there is no cell membrane separating the cells.
- tissue is contained by a single plasma membrane
What are 2 main facts about homoscleromorpha class sponges?
- spicules are siliceous
- has underlying epidermal cells
how old is the lineage of porifera?
580 million years old
Why do we think sponges are the basal group to all other animals?
- because they retain ancestral characteristics of the protist sister groups (Choanocytes)
The Porifera phylum is ___phyletic
PARAPHYLETIC
