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Mar 3
Agnatha, also known as jawless fish, are a group of primitive fish that lack jaws and paired fins. They are characterized by their cylindrical bodies, lack of scales, and cartilaginous skeletons. Agnatha includes two main groups: hagfish and lampreys.
Some key characteristics of Agnatha include:
1. Lack of jaws: Agnatha do not have true jaws, instead, they have a circular, toothed mouth that they use to feed on small invertebrates and dead or dying fish.
2. Cartilaginous skeletons: Agnatha have skeletons made of cartilage, rather than bone.
3. Lack of paired fins: Agnatha do not have paired fins like other fish, instead, they have a single dorsal fin.
4. Lack of scales: Agnatha do not have scales covering their bodies, instead, they have smooth, slimy skin.
The development of the ammocoete larva is a unique characteristic of lampreys. The ammocoete larva is the larval stage of a lamprey, which hatches from an egg and spends several years living in freshwater streams and rivers. During this stage, the ammocoete larva burrows into the sediment at the bottom of the water and filters small particles of organic matter for food.
As the ammocoete larva grows and develops, it undergoes metamorphosis into the adult lamprey. During this process, the larva develops eyes, a circular mouth with teeth, and a sucking disk that it uses to attach to and feed on the blood of other fish. The adult lamprey then migrates to the ocean to spawn and reproduce before returning to freshwater to die.
Overall, the development of the ammocoete larva is a crucial stage in the life cycle of lampreys and is essential for their survival and reproduction.
Some key characteristics of Agnatha include:
1. Lack of jaws: Agnatha do not have true jaws, instead, they have a circular, toothed mouth that they use to feed on small invertebrates and dead or dying fish.
2. Cartilaginous skeletons: Agnatha have skeletons made of cartilage, rather than bone.
3. Lack of paired fins: Agnatha do not have paired fins like other fish, instead, they have a single dorsal fin.
4. Lack of scales: Agnatha do not have scales covering their bodies, instead, they have smooth, slimy skin.
The development of the ammocoete larva is a unique characteristic of lampreys. The ammocoete larva is the larval stage of a lamprey, which hatches from an egg and spends several years living in freshwater streams and rivers. During this stage, the ammocoete larva burrows into the sediment at the bottom of the water and filters small particles of organic matter for food.
As the ammocoete larva grows and develops, it undergoes metamorphosis into the adult lamprey. During this process, the larva develops eyes, a circular mouth with teeth, and a sucking disk that it uses to attach to and feed on the blood of other fish. The adult lamprey then migrates to the ocean to spawn and reproduce before returning to freshwater to die.
Overall, the development of the ammocoete larva is a crucial stage in the life cycle of lampreys and is essential for their survival and reproduction.
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Adiba Khan
Jun 20
Agnatha Lack of jaws:
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