#reptiles
#amphibians

Reptiles
It’s estimated that there are more than 10,000 species of Reptile on the planet, and they can be found on every continent except Antarctica.
Reptiles are ectothermic, which means they get their body heat from external sources. Reptiles bask in the sun when cool and seek shade or water when hot.
Reptiles are among the longest-lived species on the planet. The Aldabra tortoise can live for over 150 years!
Reptiles first appear in the fossil record 315 million years ago.
Reptiles do not have sweat glands and thus are not slimy, instead their skin is usually cool and dry.
A snake’s scales are made of keratin, the same substance that makes up our hair and fingernails.
Some species of gecko can detach their tails in defense. When a predator grabs the tail, the gecko can detach the tail and make its escape.
Most species of snake lay eggs (oviparous). But many Vipers, Rattlesnakes and Anacondas give birth to live young (viviparous).
The hearts of snakes, lizards, turtles and tortoises contain three chambers rather than the four chambered hearts of humans.
Many species of Turtle show temperature-depend sex determination. This means the ambient temperature outside the egg, during the development of the embryo, can determine a hatchling's gender.

About Reptiles
Reptiles are air-breathing vertebrates covered in special skin made up of scales, bony plates, or a combination of both.

They include crocodiles, snakes, lizards, turtles, and tor- toises. All regularly shed the outer layer of their skin. Their metabolism depends on the temperature of their environment.

Unlike birds and mammals, reptiles do not maintain a constant internal body temperature. Without fur or feathers for insulation, they cannot stay warm on a cold day, and without sweat glands or the ability to pant, they cannot cool off on a hot one. Instead, they move into the sun or into the shade as needed. During cooler parts of the year they become inactive. Because of their slow metabolism and heat-seeking behavior, reptiles are cold-blooded.

Reptile reproduction also depends on temperature. Only boas and pythons give birth to live young. The other species lay their eggs in a simple nest, and leave. The young hatch days to months later. The soil temperature is critical during this time: It determines how many hatchlings will be male or female. Young reptiles can glide, walk, and swim within hours of birth. Reptiles first appear in the fossil record 315 million years ago and were the dominant animals during the Mesozoic era, which lasted for 270 million years until the extinction of the dinosaurs.

What are Amphibians?
Amphibians form a class of vertebrates. Other classes include reptiles, birds and mammals. There are over 4700 species of amphibians worldwide, making this group more diverse than mammals. Amphibians have no unique structure, like the feathers of birds, which sets them apart from all other animals, but there are a few characteristics which all amphibians share:

They are ectotherms (often referred to as cold-blooded). This means that internal temperature of amphibians depends upon that of the surrounding environment, unlike mammals that hold their body temperature constant
Amphibians have soft, generally moist skin without scales
Their eggs do not have shells and so they must be laid in water or a damp environment to keep from drying out
Amphibians go through a two-stage life cycle: 1) when an amphibian hatches, it is in a gilled larval form. In frogs and toads this larva is called a tadpole. 2) After a few weeks or months, the larvae transform into the adult form; however, the larvae may still take a few years to become mature
Biologists divide amphibians into three orders:

Frogs, including toads, found in Canada
Salamanders, found in Canada.
Caecilians or limbless amphibians, found only in the tropics
Frogs are by far the most diverse group of amphibians, with over 4000 species worldwide.
Thank you for watching.