2. Classification

4. Reptile Classification
Today, scientists classify reptiles into four major groups known as "orders." These four reptile orders are as follows:
Crocodilia (Krokodile) — crocodiles, gharials, caimans and alligators: 23 species
Sphenodontia — tuataras from New Zealand: 2 species
Squamata - about 7,900 species
LIZARDS (Echsen)
SNAKES (Schlangen)
Testudines (Schildkröten)— turtles and tortoises: approximately 300 species

5. Skin of Reptiles Reptiles skin is covered with scutes or scales.
Scales are made of keratin and are formed from the epidermis.
Snakes scales;
protect the body of the snake,
Help movement
allow moisture to be retained within
give simple or complex colouration patterns which help in camouflage
In crocodiles and turtles, the scutes are formed from the deeper dermis rather than the epidermis, and does not form the same sort of overlapping structure as snake scales. Similar dermal scutes are found in the feet of birds.

6. Skin of reptiles
The shedding of scales is called ecdysis, or, in normal usage moulting.
the old and worn skin is replaced
it helps get rid of parasites such as mites and ticks.
allows growth

7. Skeleton and movement of Reptiles
The movement of all reptiles is similar.
Even reptiles with legs move similar to the snake.
The belly remains on the floor and the legs are used to push the body along.

8. How do reptiles breathe?
Although reptiles breathe through lungs, some reptiles can also absorb oxygen in water through membranes in their mouth.

9. Reproduction of Reptiles
Reptiles generally reproduce via internal fertilisation.
Most reptiles lay eggs covered with leathery shells. The eggshell protects the embryo and keeps it from drying out, but it is flexible to allow gas exchange.
Only some reptiles, like the crocodile, look after their babies after they hatch.

10. Are birds reptiles???
Birds look very different from other reptiles, they have feathers, fly, sing complex songs, and have many other unique features.
Animal groupings are most useful when they reflect the evolutionary history of the animals in that group.
For example, "mammals" is the name of a group of animals that are all more closely related to each other than to other kinds of animals.
It's not hard to imagine that a skunk is more closely related to you than it is to a turtle, because you and a skunk both have fur (yours is mostly on your head!), you both have mothers that fed you milk, and other features. Even though you and the skunk look very different, you share features that show you share an ancestor. The "mammals" group name reflects that shared history.
Snakes, lizards, turtles, crocodilians, and birds also all share an evolutionary history. Many years of research has proven that the ancestors of birds were bird-like dinosaurs. Even though birds look very different from other living reptiles, they’re most closely related to alligators and crocodiles and clearly belong in the reptile group.