PARASITIC ADAPTATIONS IN PLATYHELMINTHES

A parasite brings about certain modifications in its structure, function and life-cycles. these modifications give suitable adaptations to various parasites. These adaptations can be summed up as follows.

A) MORPHOLOGICAL ADAPTATIONS
1. loss of locomotory organs
2. development of the organs of attachment
3. coving over the cbody
4. reduced alimentary canal
5. loss of sense organs
6. enormous development of the development organs
7. shells around their eggs.
8. hermaphroditism

B) PHYSIOLOGICAL ADAPTATIONS
1. secretion of anti-enzymes
2. production of large amount of mucous
3. anaerobic respiration
4. double parasitic life cycles
5. paedogenesis

structurally and functionally speaking, there are three types of neurons.

1. unipolar (sensory in function)
2. bipolar (sensory in function)
3. multipolar (motor and associative neurons in function)

1. unipolar
As the name implies, these neurons have just one projection originating from the cell body. These neurons are sensory in function, which means that they always carry the message from receptors to the CNS (central nervous system). The impulse however travels away from the axon to the next neuron. These neurons are the part of peripheral nervous system as they are present in the nerve.

2. bipolar
These neurons have two projection originating from the cell body. Bipolar neurons are also sensory and the part of PNS (peripheral nervous system)
e.g. bipolar cells in retina

3. multipolar
These neurons have multipal projections projecting from the cell body. multipolar neurons are motor and associative neurons in function. They are the part of CNS (central nervous system).

Both alligators and crocodiles are members of the reptilian order Crocodylia. But the families they belong to, Alligatoridae and Crocodylidae respectively, differ.

Crocodile & Alligator Differences

Crocodiles and alligators are both reptiles from the same order of animals, named Crocodylia. There are however a number of important differences which set these apex predators apart.

1. Crocodile

Crocodiles have a longer, more V-shaped head then alligators.

The fourth tooth of a crocodile sticks out when its mouth is closed.

Crocodiles are better adapted to living in seawater.

Crocodiles are more aggressive than alligators.

Crocodiles tend to have a lighter appearance than alligators.

Crocodiles in the wild are found all over the world while alligators are only found in the US and China.

2. Alligators

Alligators have shorter, wider heads that are more U-shaped than crocodiles.

Alligators strongly favor freshwater while some species of crocodile live in seawater.

Alligators are less aggressive than crocodiles.

Alligators tend to have a darker appearance than crocodiles.

Alligators in the wild are only found in the US and China while crocodiles are found all over the world.

Tortoises and Turtles are both reptiles from the family of Testudines, the major difference being that the land dwelling ones are called Tortoises and water dwelling are called Turtles. The body of a tortoise and a turtle both is shielded by a shell, the upper part of which is called Carapace and the lower portion is called Plastron. The Carapace and the Plastron are attached at the end by a bridge which means that though the head and limbs may be withdrawn from the shell, the whole body can never be totally detached from it. These reptiles are generally reclusive and shy in nature.

The differences between turtle and tortoise are as follows:

1. Definition
A Tortoise is a reptile from the Chelonian family and dwells well on land while
A Turtle is a reptile from the Chelonian family and dwells well in the water.

2. Distribution
Tortoise Found mostly in Asia and Africa but some species exist in Americas too.
Turtle is Found IN Africa, America.

3. Shape of the shell
Mostly large dome shaped shells (with bumps on the top in some species) in tortoise.
Mostly flat, streamlined shells in turtles.