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