Why do not the larva stage occurs in all the organism while it occurs in some only???
Dear student,
Larval stage usually occurs in organisms for the following reasons:
1. The habitat in which it is born is unsuitable for the adult form, eg frog, mosquitoes etc.
2. There is an abundance of predators which the adult form would not be able to excape, but the larva can, due to smaller size, and unrecognizable shape.
3. If the offsprings are formed inside the host in the infective organisms, then the larva stage is present which is best suitable for the internal environment of the host. This is seen in cases where the adult forms cannot be transferred from host to host for spread of infection.
4. For procurement of food during inittial growth, where large amounts of nutrition is required, in cases where the adult has a sedentary lifestyle, eg coelenterates.
When these circumstances are not present the need for larvae stage is removed. The adult form can itself survive. Therefore, some organisms have larvae, while some don't.
Regards!
Larval stage usually occurs in organisms for the following reasons:
1. The habitat in which it is born is unsuitable for the adult form, eg frog, mosquitoes etc.
2. There is an abundance of predators which the adult form would not be able to excape, but the larva can, due to smaller size, and unrecognizable shape.
3. If the offsprings are formed inside the host in the infective organisms, then the larva stage is present which is best suitable for the internal environment of the host. This is seen in cases where the adult forms cannot be transferred from host to host for spread of infection.
4. For procurement of food during inittial growth, where large amounts of nutrition is required, in cases where the adult has a sedentary lifestyle, eg coelenterates.
When these circumstances are not present the need for larvae stage is removed. The adult form can itself survive. Therefore, some organisms have larvae, while some don't.
Regards!