Yes, earthworm has 4 pairs of hearts but according to few web pages in google there are 5 aortic hearts in earthworms.

Heart in Earthworms

Earthworms are elongated, tube-shaped segmented worms belonging to the phylum Annelida. They are known for their important role in soil fertility and decomposition. Like other annelids, earthworms possess a closed circulatory system, which means they have a dedicated organ for pumping blood. In earthworms, this organ is known as the heart.

The Number of Hearts in Earthworms

Contrary to popular belief, earthworms do not have multiple hearts. Instead, they have a single heart, which is located in the anterior region of their body. The heart of an earthworm is a muscular tube that runs along the dorsal side of its body. It consists of several chambers called aortic arches, which contract and relax to pump blood throughout the worm's circulatory system.

The Functions of the Earthworm's Heart

The primary function of the earthworm's heart is to circulate blood and transport nutrients, oxygen, and waste products throughout its body. The blood, also known as hemolymph, flows through the dorsal blood vessel, which is located above the intestine. The heart contracts rhythmically, pushing the hemolymph forward through the aortic arches. This pumping action creates circulation within the earthworm's circulatory system.

The Circulatory System of Earthworms

The circulatory system of an earthworm is relatively simple compared to higher organisms. It consists of the following components:

1. Dorsal blood vessel: This vessel runs along the upper side of the intestine and carries the hemolymph.

2. Aortic arches: Earthworms have five pairs of aortic arches that act as muscular pumps to propel the blood forward.

3. Capillaries: After leaving the aortic arches, the blood flows into a network of capillaries, which are tiny blood vessels that allow for the exchange of nutrients, oxygen, and waste products with the surrounding tissues.

4. Ventral blood vessel: The blood eventually returns to the ventral side of the earthworm's body through the ventral blood vessel.

In conclusion, earthworms have a single heart that pumps blood throughout their circulatory system. The heart consists of a series of aortic arches that contract and relax to circulate the hemolymph. While earthworms may not have multiple hearts like some other organisms, their singular heart serves the vital function of maintaining circulation and facilitating the exchange of nutrients and waste products within their bodies.

4 pairs