Adaptions.

Structual
The tuatara resembles an ordinary lizard in appearance, but it is so radically different, it is classified in its own order, as well as its own family. It is characterised by a second bony bridge in its skull which is also found in crocodilians, but is lost in lizards and snakes.Tuatara are also unusual because they have a third 'eye'. They have two normal eyes. The third eye is on top of their head, in between their other eyes. It does not see like a normal eye. The parietal eye, as it is called, is only visible in hatchlings.Tuataras do not have ears, but they can hear.

Behavioural.
Adult tuatara are nocturnal reptiles,though they will often bask in the sun to warm their bodies.The optimal body temperature for the tuatara is from 16 to 21 °C (61 to 70 °F), the lowest of any reptile.Tuatara probably have the slowest growth rates of any reptile, continuing to grow larger for the first 35 years of their lives.The average lifespan is about 60 years, but they can live to be well over 100 years old. Some experts believe captive tuatara could live as long as 200 years.

Physilogical,
Tuatara reproduce very slowly, taking 10 to 20 years to reach sexual maturity.Mating occurs in midsummer; females mate and lay eggs once every four years. During courtship, a male makes his skin darker, raises his crests, and parades toward the female. He slowly walks in circles around the female with stiffened legs. The female will either submit, and allow the male to mount her, or retreat to her burrow. Males do not have a penis; they reproduce by the male lifting the tail of the female and placing his vent over hers. The sperm is then transferred into the female, much like the mating process in birds.

Analyse the importance.
These adaptions are very important to the tuatara because originally the tuatara would not be able to survive. They are using these adaptions to survive and create their offspring for easily.
They use their other special parts to help them live in the islands and keep away from predators.

Evaluate.
These adaptions may have come about when the tuatara lived in the wild. They would of needed to protect themselves and be able to live without getting killed. It could of been also when they lived in the offshore islands.Where along with their different enviornment changed they body.