Lecture 6
Ctenophora
- Comb jellies
- 8 Ctenes (comb rows of cilia)
- ~150 species
- Biradial symmetry
- Colloblast cells (sticky)
Ctenes
- Swim from beating cilia mouth-forward
- Statocyst
- Helps with balance and orientation
- Contains sensory vesicles
- Nerve net similar to Cnidarians
Body forms + Reproduction
- Primarily free swimming but do have creeping and sessile forms
- Usually found at the surface
- Monoecious (gametes shed into water)
- Some undergo internal fertilization
Colour?
- Mostly colourless and transparent (deep sea species red)
- Luminescence (blue + green)
- Refraction
Bilateria
- Triploblastic
- Three embryonic germ layers
- Ectoderm, endoderm and mesoderm
- Body cavities
- Acoelomate
- Pseudocoelomate
- Eucoelomate
- Cephalization
- Anterior and posterior end
- Mouth in head region
- Development of sense organs at anterior end to sense environment
- Being bilateral leads to movement in one direction
, Lecture 7
Xenacoelomorpha (Phylum)
● Xenoturbellids and Acoelomorpha
● Triploblasts (basal)
● Mainly parasitic
● Body shapes
○ Acoelomate (no body cavity)
○ Bilateral
○ Vermiform (worm-like structure)
● No anus
● Flame cells (excretion and osmoregulation)
● Reproduction
○ Well developed
○ Most hermaphrodites (male and female organs)
● Four classes
○ Phylogeny under debate
Platyhelminthes
● Acoelomate body (Parenchyma distinctive from connecting and supporting
tissue)
● Dorso-ventrally flattened
● Triploblasts (protosome - lophotrochozoa)
● Flame cells
○ Filters fluids
○ Removes waste
○ Controls osmotic pressure
○ Flame cells + tube cell = Protonephridia
Turbellaria
● Small or large
● Swim with muscles, cilia and slime
● Skin and muscle
○ Ciliated epidermis
○ Epidermis contains Rhabdites (rod-shaped secretory products)
○ Attach and detach system
■ Dual Gland adhesive organs
● Feeding
○ Muscular Phyarynx in ventral centre of body
Ctenophora
- Comb jellies
- 8 Ctenes (comb rows of cilia)
- ~150 species
- Biradial symmetry
- Colloblast cells (sticky)
Ctenes
- Swim from beating cilia mouth-forward
- Statocyst
- Helps with balance and orientation
- Contains sensory vesicles
- Nerve net similar to Cnidarians
Body forms + Reproduction
- Primarily free swimming but do have creeping and sessile forms
- Usually found at the surface
- Monoecious (gametes shed into water)
- Some undergo internal fertilization
Colour?
- Mostly colourless and transparent (deep sea species red)
- Luminescence (blue + green)
- Refraction
Bilateria
- Triploblastic
- Three embryonic germ layers
- Ectoderm, endoderm and mesoderm
- Body cavities
- Acoelomate
- Pseudocoelomate
- Eucoelomate
- Cephalization
- Anterior and posterior end
- Mouth in head region
- Development of sense organs at anterior end to sense environment
- Being bilateral leads to movement in one direction
, Lecture 7
Xenacoelomorpha (Phylum)
● Xenoturbellids and Acoelomorpha
● Triploblasts (basal)
● Mainly parasitic
● Body shapes
○ Acoelomate (no body cavity)
○ Bilateral
○ Vermiform (worm-like structure)
● No anus
● Flame cells (excretion and osmoregulation)
● Reproduction
○ Well developed
○ Most hermaphrodites (male and female organs)
● Four classes
○ Phylogeny under debate
Platyhelminthes
● Acoelomate body (Parenchyma distinctive from connecting and supporting
tissue)
● Dorso-ventrally flattened
● Triploblasts (protosome - lophotrochozoa)
● Flame cells
○ Filters fluids
○ Removes waste
○ Controls osmotic pressure
○ Flame cells + tube cell = Protonephridia
Turbellaria
● Small or large
● Swim with muscles, cilia and slime
● Skin and muscle
○ Ciliated epidermis
○ Epidermis contains Rhabdites (rod-shaped secretory products)
○ Attach and detach system
■ Dual Gland adhesive organs
● Feeding
○ Muscular Phyarynx in ventral centre of body
