What are the cells called that flatworms use to detect changes in the amount of light in their environment?
3.38). Sensory cells in the head detect changes in the environment. In free-living flatworms, sensory cells that respond to light are clustered in two eyespots in the head. Sensory cells that detect water currents, solid objects, and chemicals are in two flap-like projections on the head called auricles.
What annelid is an external parasite?
Leeches probably evolved from oligochaetes, and are the most specialized of annelids. Some leeches are predaceous, but most are external parasites of other animals, and have several adaptations for a parasitic lifestyle.
What does a tapeworm uses its scolex for?
the tapeworm uses its scolex to attach to the intestinal wall of its host where it absorbs nutrients from the host’s intestine.
What is each cluster of nerve cells that controls a flatworm’s nervous system called?
In the flatworm Planaria, the brain consists of two cerebral ganglia (clusters of nerve cells) from which nerve cords extend the length of the body.
What structures on the scolex fasten the tapeworm to the intestinal wall?
Its tiny attachment, the scolex, contains suckers and a rostellum as organs of attachment that attach to the wall of the small intestine. The main body, consists of a chain of segments known as proglottids.
How do flatworms and roundworms differ from annelids?
Annelids differ from flatworms and roundworms by how they digest their food. An annelid has a complete digestive tract with 2 openings that can process food and absorb nutrients as the meal moves from mouth to anus.
What is the major morphological innovation seen in annelid worms?
Annelids display bilateral symmetry and are worm-like in overall morphology. Annelids have a segmented body plan wherein the internal and external morphological features are repeated in each body segment. Metamerism allows animals to become bigger by adding “compartments” while making their movement more efficient.
What is the difference between Proglottids and scolex?
The scolex contains organs which facilitate attachment to the host tissue. Examples of this include suckers or hooks. Proglottids are individual segments of the strobilus and contain reproductive organs of both sexes. The proglottids at the posterior end are mature in comparison to the ones at the anterior end.
What are the two structures on the scolex of Taenia Solium?
Nervous system of T. solium (Fig. 42.5) consists of two small cerebral ganglia in the scolex connected together by a thick transverse nerve band and by the dorsal and ventral commissures. All these structures together are referred to as the brain complex.
What type of nervous system is typical for Coelenterates?
Present-day coelenterates include the Cnidaria (e.g., hydroids, jellyfish, sea anemones, corals) and the Ctenophora (combjellies). They have the simplest nervous system in the animal kingdom, possessing diffuse nerve nets and epithelial electrical conduction.
Where is the flatworm’s mouth?
Flatworms possess a ‘blind gut’, they have a mouth but no opening at the lower end of the alimentary canal through which solid waste is eliminated from the body.
