CLASSIFICATION Flashcards
How many classes has the Phylum Platyhelminthes? Name them.
Four
- Class Turbellaria
- Class Monogenea
- Class Trematoda
- Class Cestoidea
What are the characteristic features of the Phylum Platyhelminthes?
- Dorso-ventrally flattened body
- Are tribloplastic
- Bilateral symmetry
- Acoelomates
- Have organs embedded in parenchyma
- Respiratory,circulatory and skeletal systems lacking.
- Monoecious (hermaphroditic)
- Turbellarians are mostly free-living, the rest are entirely parasitic.
- ingestion is through the mouth, so is egestion.
Give characteristics of the class Turbellaria.
- Gut made of endoderm
- Skin and muscles-ectoderm
- The rest is mesoderm
- Mostly free-living with ciliated epidermis
- Voracious carnivores, usually eat worms and crusteceans.
- Mostly marine,freshwater or terrestrial.
How does locomotion take place in Turbellarians?
by muscular and ciliary movement.
How does digestion take place in Class Turbellaria?
Small prey are taken into the gut and surrounded with enzymes. Fats are directly broken down into soluble foods. Proteins and carbohydrates are absorbed and digested by the cells lining the gut.
What is intracellular and extracellular digestion?
Intracellular digestion is the breakdown of food substances into soluble particles for respiration, it occurs within the cells.
Extracellular digestion takes place outside the cells.
Excretion
Metabolic waste removed largely by diffusion through body wall.
Respiration
No respiratory organs, exchange of gases thrrough body surface.
How does reproduction take place?
Asexually; by fission. For example, freshwater planarian merely constricts behind pharynx, separates into two animals and regenerates missing parts.
Sexually; they are monoecious, but practice cross-fertilization. after copulation, fertilized eggs and yolk cells become enclosed in cocoon. Embryos emerge as juveniles.
What other name are Treamtodes known by?
Flukes.
What is the range of body size?
few mm to 8cm.
Give characteristics of the class Turbellaria.
- Gut made of endoderm
- Skin and muscles-ectoderm
- The rest is mesoderm
- Mostly free-living with ciliated epidermis
- Voracious carnivores, usually eat worms and crusteceans.
- Mostly marine,freshwater or terrestrial.
How does locomotion take place in Turbellarians?
by muscular and ciliary movement.
How does digestion take place in Class Turbellaria?
Small prey are taken into the gut and surrounded with enzymes. Fats are directly broken down into soluble foods. Proteins and carbohydrates are absorbed and digested by the cells lining the gut.
What is intracellular and extracellular digestion?
Intracellular digestion is the breakdown of food substances into soluble particles for respiration, it occurs within the cells.
Extracellular digestion takes place outside the cells.
