Learning Target: Reptiles are the first vertebrates to spend their entire lives on land.
There are four main groups of Reptiles:
- lizards
- snakes
- turtles
- crocodiles
Reptiles evolved soon after amphibians and are closely related to them. However, animals in the reptile group have adaptations that allow them to survive in hotter, drier places than amphibians. For many millions of years they were the largest and most diverse vertebrate animal group living on land.
Reptiles have the following characteristics:
- Usually two pairs of legs, for a total of four limbs.
- tough, dry skin covered by scales
- they obtain oxygen from air with respiratory organs called lungs.
- their sensory organs are adapted for sensing on land
- they lay their eggs, which have shells, on land.
Lungs
Reptiles do not get oxygen through their skin the way amphibians do. They are born with lungs that provide their bodies with all the oxygen they need. When an animal with lungs inhales, it takes air in through its nostrils or mouth and moves the air into its lungs. There, oxygen is transported across the tissues and into the blood, and carbon dioxide is moved from the blood to the lungs and exhaled.
Reptiles do not get oxygen through their skin the way amphibians do. They are born with lungs that provide their bodies with all the oxygen they need. When an animal with lungs inhales, it takes air in through its nostrils or mouth and moves the air into its lungs. There, oxygen is transported across the tissues and into the blood, and carbon dioxide is moved from the blood to the lungs and exhaled.
Dry, Scaly Skin
Reptile skin is hard, dry, and covered with scales made of keratin, a substance similar to human finger nails. The thick, waterproof skin of reptiles protects them from the environment and from predators.
Reptile skin is hard, dry, and covered with scales made of keratin, a substance similar to human finger nails. The thick, waterproof skin of reptiles protects them from the environment and from predators.
Eggs with Shells
The reptile egg is an important adaptation that allows vertebrate animals to survive in hot, dry environments. The eggs of reptiles contain everything an embryo needs:
Reptiles reproduce sexually. The egg cell of the female joins with the sperm cell of the male in the process of fertilization. After fertilization, a protective case, or shell, forms around each egg while it is still inside the females' body. The female selects a place to lay the eggs on land. Many species of reptiles build or dig nests. Some female reptiles, including alligators, guard their nests and care for their offspring (PARENT) after they hatch. Most reptiles, however, leave soon after the eggs are laid.
Boa Constrictors and Pythons give birth to live young.
The reptile egg is an important adaptation that allows vertebrate animals to survive in hot, dry environments. The eggs of reptiles contain everything an embryo needs:
- Water
- nutrients
- gas exchange
- waste storage
Reptiles reproduce sexually. The egg cell of the female joins with the sperm cell of the male in the process of fertilization. After fertilization, a protective case, or shell, forms around each egg while it is still inside the females' body. The female selects a place to lay the eggs on land. Many species of reptiles build or dig nests. Some female reptiles, including alligators, guard their nests and care for their offspring (PARENT) after they hatch. Most reptiles, however, leave soon after the eggs are laid.
Boa Constrictors and Pythons give birth to live young.
All reptiles are ectotherms...cold blooded!