Biology: Flatworms Characteristics

Characteristics of Flatworms

• Have dorso-ventrally flattened bodies, hence called flatworms
• Mostly endoparasites found in animals, including human beings
• Bilaterally symmetrical, triploblastic, and acoelomate animals
• Organ level of organisation

Features of Parasitic Forms

• Have hooks and suckers
• Absorb nutrients from the host directly through their body surface

Osmoregulation and Excretion

• Specialised cells called flame cells help in osmoregulation and excretion

Reproduction and Development

• Sexes are not separate
• Fertilisation is internal
• Development is through many larval stages

Regeneration Capacity

• Some members, like Planaria, possess high regeneration capacity

Examples of Flatworms

• Taenia (Tapeworm)
• Fasciola (Liver fluke)

Characteristics of Aschelminthes

• The body of Aschelminthes is circular in cross-section, earning them the name "roundworms".
• They exhibit organ-system level of body organization.

Body Structure

• Aschelminthes are bilaterally symmetrical, triploblastic, and pseudocoelomate animals.
• They have a complete alimentary canal with a well-developed muscular pharynx.
• An excretory tube is present to remove body wastes from the body cavity through the excretory pore.

Reproduction

• Sexes are separate (dioecious), with males and females being distinct.
• Females are often longer than males.
• Fertilization is internal, and development may be direct (young ones resemble the adult) or indirect.

Examples of Aschelminthes

• Ascaris (Roundworm)
• Wuchereria (Filaria worm)
• Ancylostoma (Hookworm)

This quiz covers the characteristics of flatworms, including their body structure, symmetry, and organ organisation. It also touches on their parasitic nature and specialised cells.