BIOL2712 Study Guide - Final Guide: Chemotaxonomy, Phagocytosis, Digestion
25 Jun 2018
School
Department
Course
Professor
Mesozoa & Porifera
Protozoa Mesozoa Metazoa
Protozoa
Unicellular animals
oLike protists without tissues or organs
oExisting singly or in colonies of a few to many individuals
Such colonies differ from a metazoan in that their components are all alike except
when engaged in reproduction
Mesozoa “middle animals”
100 species
Cellular endoparasites that during all or part of the life cycle are composed of an
outer cell layer or syncytium
oenclosing one or more reproductive cells
<50 cells (usually 20-30 cells)
Solid 2-layered construction
oBut their 2 layers do not correspond to the ectoderm and endoderm of
Metazoa
Remnant from early stage of animal evolution or degenerate from Plathelminthes?
Mesozoans
The Orthonectida
oAmoeba shaped, no cilia
oParasitizes a range of marine invertebrates
Rhombozoans
oLong thin and ciliated
oCephalopod parasites
Metazoan “differentiated animals”
Composed of numerous cells differentiated into many sorts to perform different
functions
Arrangement of at least part of their cells into layers
Formation of a nervous system whose centralization tends toward anterior end or
head
Occurrence of embryonic development in the life history
find more resources at oneclass.com
find more resources at oneclass.com
Parazoa = Phylum Porifera
Porifera = pore bearing
oParazoa = beside animals
Common name:
oSponges
10,000 described species
Distribution
oMainly marine but some freshwater demosponges
Sponges
oSessile (attached) animals
oNo true tissues
oSuspension feeders
oWide variety of shapes and sizes
Basic Body Plan
Collection of
(mostly) identical
cells within a
gelatinous matrix
supported by
skeleton of protein
and/or spicules of
Ca and/or Si
Cells loosely
aggregated, no
germ layers, all of
mesenchymal
(stem cells) origin
No nervous system
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Unicellular animals: like protists without tissues or organs, existing singly or in colonies of a few to many individuals. Such colonies differ from a metazoan in that their components are all alike except when engaged in reproduction. Cellular endoparasites that during all or part of the life cycle are composed of an outer cell layer or syncytium: enclosing one or more reproductive cells. Solid 2-layered construction: but their 2 layers do not correspond to the ectoderm and endoderm of. The orthonectida: amoeba shaped, no cilia, parasitizes a range of marine invertebrates. Rhombozoans: long thin and ciliated, cephalopod parasites. Composed of numerous cells differentiated into many sorts to perform different functions. Arrangement of at least part of their cells into layers. Formation of a nervous system whose centralization tends toward anterior end or head. Occurrence of embryonic development in the life history. Porifera = pore bearing: parazoa = beside animals. Distribution: mainly marine but some freshwater demosponges.
