Download - Biology homework
Classification/Evolution project
About: Mollusca and Cnidaria
MolluscaCommon name: Molluscs or mollusks
Characteristics of mollusca
A very varied range of body structures, so it is difficult to find charasterictics that apply for all species of mollusca.
Invertebrate animals
Mantle with a cavity for breathing and excretion
Bilaterally symmetrical and unsegmented
Two pairs of main ventral nerve cords
Adaptations and special features of
Mollusca Mollusks are all soft-bodied
Most are marine, though there are exceptions with terrestial and freshwater living species.
Forms vary from chitons and snails to clams and squids
No body segmentation, instead their bodies are divided into three body regions, the head, mass of internal organs, and a kind of foot.
A radula, used for feeding, a kind of tongue which is used for scraping and cutting food.
Mollusca and Cnidaria on the tree of life
Both Mollusca and Cnidaria can be found in the kingdom Animalia
Relations to other organisms
Mollusks are grouped under the superphylum Lophotrochozoa, together with Nemertea, Sipuncula, and Annelida.
They were earlier grouped together with arthropods, but they are now placed separately among the Ecdysozoa
Mollusks probably evolved from a flatworm resembling ancestor during the Precambium era.
Nautilus, a species of Mollusca
CnidariaMostly recognized as Medusae and Polyps
Characteristics of Cnidaria
Aquatic invertebrates, mostly marine
Largest part of their body is made of water
Radially symmetric bodies
”Cnidocytes” where also the name ”Cnidaria” comes from, are venomous cells used to stun and capture prey
Have a single ofrice and body cavity that is used for both digestion and respiration
Adaptations and special features of
Cnidaria Adapted to an aquatic environment by having a ”hydrostatic skeleton”, which is a water filled body cavity surrounded by muscles.
They have interstitial cells which let them regrow lost limbs, such as parts of their tentacles
They do not have teeth, instead they use their tentacles to drag prey to their ”mouth”
Anemones, a subclass of cnidarians
Kingdom:AnimaliaPhylum: CnidariaClass: ScyphozoaOrder: CoronataeFamily: NausithoidaeGenus: NausithoeSpecies: N. aurea
Kingdom:AnimaliaPhylum: MolluscaClass: Gastropoda(unranked):clade HeterobranchiaInformal group Opisthobranchiaclade Sacoglossaclade OxynoaceaSuperfamily:OxynooideaFamily: JuliidaeGenus: BertheliniaSpecies: B. chloris
SOURCES http://zoology.muohio.edu/crist/zoo312/
molluscs.html
http://en.wikipedia.org/wiki/Arthropod
http://en.wikipedia.org/wiki/Mollusca
http://www.earthlife.net/inverts/mollusca.html
http://en.wikipedia.org/wiki/Cnidaria