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The animals in the Annelida are segmented worms. They have no legs, and no hard skeleton. Unlike mollusks, annelid bodies are divided into many little segments, like rings joined together. There are many other kinds of worms, but only annelids are segmented this way.
- How long can annelids live?
- Do annelids have eyes?
- What special features do annelids have?
- Are annelids cold blooded?
- How do annelids eat?
- Can annelids swim?
- Do annelids lay eggs?
- How do annelids breathe?
- Do annelids have a brain?
- How many hearts do annelids have?
- Do annelids have legs?
- Do annelids have hearts?
- What feature do we first see evolutionarily with annelids?
- How do annelids defend themselves?
How long can annelids live?
Aquatic annelids seem to live a maximum of 1 or 2 years and generally breed only once, with leeches living the longest.
Do annelids have eyes?
Pigmented ocelli and eyes in Annelida. Most polychaete species have an eye of one type or another, whereas these organs are a rare exception in the large taxon Clitellata. ... Usually eyes of polychaetes are situated within or in close association with the brain and, therefore, are termed cerebral eyes (Fig. 1, Fig.
What special features do annelids have?
annelid, phylum name Annelida, also called segmented worm, any member of a phylum of invertebrate animals that are characterized by the possession of a body cavity (or coelom), movable bristles (or setae), and a body divided into segments by transverse rings, or annulations, from which they take their name.
Are annelids cold blooded?
The annelids like earthworm, leech, nereis are ectotherms. Their body temperature fluctuates with temperature of environment.
How do annelids eat?
Burrowing annelids, like the earthworm, play an important role in helping organic matter decompose. Earthworms eat dead plants and animals. When they eat, they also take in soil and tiny pebbles. Earthworms take in nutrients from microorganisms in the material they ingest.
Can annelids swim?
Swimming is frequently seen in annelids and is normally facilitated by a combination of body and parapodial movements in errantians.
Do annelids lay eggs?
Earthworms are hermaphrodites, which means that each animal has both male and female reproductive organs in the same body. Earthworms lay their eggs in a cocoon that is then deposited in the soil. On hatching the young worms resemble small adults and will grow continually until they reach maturity.
How do annelids breathe?
They breathe through their skin. Air dissolves on the mucus of their skin, so they MUST stay moist to breathe. If worms dry out, they suffocate. As fresh air is taken in through the skin, oxygen is drawn into the worm's circulatory system, and the worm's hearts pump the oxygenated blood to the head area.
Do annelids have a brain?
In most annelids (segmented worms) such as the earthworm, two cerebral ganglia (bundles of nerve cells) form a primitive bilobed brain, from which sensory and motor nerve fibres lead to other areas of the body. ... Two to five pairs of lateral nerves leave each ganglion to innervate the body wall of that segment.
How many hearts do annelids have?
The earthworm, which is perhaps the most popular of all the annelids, has five heart-like structures called aortic arches. Along with dorsal and ventral vessels, the aortic arches help blood flow through the closed circulatory system and reach both ends of the body.
Do annelids have legs?
The animals in the Annelida are segmented worms. They have no legs, and no hard skeleton. Unlike mollusks, annelid bodies are divided into many little segments, like rings joined together.
Do annelids have hearts?
Annelids do not have a central, well-developed heart, and usually the muscular dorsal blood vessel functions to pump blood through the circulatory system. ... Earthworms have five of these muscular, heart-like vessels located in the front region of the body.
What feature do we first see evolutionarily with annelids?
Coelom. An important evolutionary development in annelids, that is not obvious when you see the animal from the outside, is the presence of a well-developed coelom, or body cavity. Along with mollusks, annelids are among the first animals to have a coelom.
How do annelids defend themselves?
They have small bristles, known as setae, which are both sensing devices that can identify any soil vibrations and digging aids. The setae stick to dirt and the worm then contracts its body to force itself through soil. The worm also secretes a mucus that helps it slide through dirt more quickly.
