K.1 segmented worms

What is Phylum Annelida?

Segmented worms.

What key feature defines annelids?

Segmented body structure.

What body cavity do annelids have?

A coelom.

Why is the coelom important?

It allows development of organs like blood vessels, muscles, and digestive structures.

What systems become more specialized due to a coelom?

Circulatory, respiratory, excretory, and digestive systems.

What are body segments in annelids called?

Repeating anatomical units along the body.

What divides the coelom into segments?

Septa.

Why is segmentation important?

It allows specialized organs and efficient movement.

What are the three main classes of annelids?

Oligochaeta, Polychaeta, Hirudinea.

What is an example of Oligochaeta?

Earthworm (Lumbricus).

What does 'oligochaeta' mean?

'Few bristles.'

What structure defines Oligochaeta?

Setae (bristles).

How many setae per segment do oligochaetes have?

Two pairs per segment.

What is the clitellum?

A thickened reproductive band that secretes slime during reproduction.

What is an example of Polychaeta?

Nereis (sandworm), tubeworms.

What does 'polychaeta' mean?

'Many bristles.'

What structure do polychaetes have instead of setae?

Parapodia (fleshy lateral extensions).

What is the lifestyle of many polychaetes?

Predatory or filter-feeding.

What is an example of Hirudinea?

Leeches.

What is the main lifestyle of leeches?

Parasitic.

What structures do leeches use to attach to hosts?

Anterior and posterior suckers.

What is hirudin?

A chemical that acts as an anticoagulant and anesthetic.

What muscles allow annelid movement?

Circular and longitudinal muscles.

What do circular muscles do?

Constrict the body.

What do longitudinal muscles do?

Shorten the body.

Why can annelids move efficiently?

Muscle layers act independently of digestion.

What is the first digestive structure after the mouth?

Pharynx.

What is the function of the crop?

Temporary food storage.

What is the function of the gizzard?

Grinding food.

What does the intestine do?

Absorbs nutrients.

What are earthworm waste deposits called?

Castings.

Do annelids have a closed circulatory system?

Yes.

What are the main blood vessels in earthworms?

Dorsal and ventral blood vessels.

What are aortic arches?

Segmental vessels that act like hearts.

What type of nervous system do annelids have?

Ventral nerve cord system.

What is the brain structure in earthworms?

Bi-lobed dorsal brain.

What organs do annelids use for excretion?

Nephridia.

What do nephridia do?

Filter waste and release it through pores in the cuticle.

Are earthworms hermaphroditic?

Yes.

What is the role of the clitellum?

Produces mucus for reproduction and cocoon formation.

Does fertilization occur inside or outside the earthworm?

Outside.

What larval stage do earthworms produce?

Trochophore larva.

How do earthworms improve soil?

They aerate it and improve water/nutrient flow.

Why are earthworms important for plants?

They increase nitrates in soil, enhancing plant growth.

What is the economic importance of earthworms?

Used as fish bait.

How do leeches feed?

By sucking blood from hosts.

What does hirudin do?

Prevents blood clotting and reduces pain detection.

Why are leeches used in medicine?

They improve blood flow after surgery by preventing clotting.