Characteristics of Reptiles By Jerit Owens

Scaly Skin Dry thick skin covered with scales Dry thick skin covered with scales Prevents water loss Prevents water loss Adds protection against predators Adds protection against predators Skin does NOT play a role in respiration in reptiles. They can only respire through their lungs. Skin does NOT play a role in respiration in reptiles. They can only respire through their lungs.

Skeletal Features Compared to Amphibians Legs are placed directly under body than at right angles, unlike amphibians. Legs are placed directly under body than at right angles, unlike amphibians. This provides greater support for walking and running. This provides greater support for walking and running. Reptiles have claws for catching prey and for protection. Reptiles have claws for catching prey and for protection. More evolved jaws and teeth. More evolved jaws and teeth.

Some have Four-chambered Hearts Most have three chambered hearts Most have three chambered hearts Crocodilians have four chambered hearts Crocodilians have four chambered hearts This separates deoxygenated blood from oxygenated blood. This separates deoxygenated blood from oxygenated blood. Enables more oxygen to reach tissues. Enables more oxygen to reach tissues. Supports high level of energy use. Supports high level of energy use.

Reproduce on Land Lay eggs on land Lay eggs on land No water larval stage, so they are not at risk to water predators like amphibians No water larval stage, so they are not at risk to water predators like amphibians No type of metamorphosis, hatchlings look just like adults No type of metamorphosis, hatchlings look just like adults Evolution of the amniotic egg freed reptiles from reproduction in water. Evolution of the amniotic egg freed reptiles from reproduction in water. Amniotic egg nourishes and protects the developing embryo in terrestrial habitats. Amniotic egg nourishes and protects the developing embryo in terrestrial habitats.

Reproduce on Land (cont’d) Embryo relies on egg for survival until it hatches. Embryo relies on egg for survival until it hatches. All have internal fertilization All have internal fertilization Eggs are laid after fertilization Eggs are laid after fertilization Reptiles lay eggs in safe places, away from predators Reptiles lay eggs in safe places, away from predators Most reptiles provide no care for hatchlings. Most reptiles provide no care for hatchlings.

Reptiles are Ectotherms Similar to amphibians because they are both ectotherms. Similar to amphibians because they are both ectotherms. Rely on outer environment for regulation of body temperature. Rely on outer environment for regulation of body temperature. Because of this feature, they don’t live in extremely cold regions. Because of this feature, they don’t live in extremely cold regions. Many become dormant in cold seasons. Many become dormant in cold seasons. This lizard is sun bathing to get warm.

Obtaining Food Slow animals like turtles and tortoises are herbivores or they prey on worms and mollusks. Slow animals like turtles and tortoises are herbivores or they prey on worms and mollusks. Fast turtles can prey on fish and amphibians Fast turtles can prey on fish and amphibians Most lizards eat insects Most lizards eat insects Marine iguanas from the Galapagos Islands eat algae. Marine iguanas from the Galapagos Islands eat algae. Komodo dragons are carnivorous and feed on large animals including humans. Komodo dragons are carnivorous and feed on large animals including humans. This marine iguana is brightly colored from eating algae in the Galapagos Islands.

Obtaining Food (cont’d) Some snakes like rattle snakes have fangs for capturing prey. Some snakes like rattle snakes have fangs for capturing prey. Other large snakes use methods of constriction to suffocate their prey. Other large snakes use methods of constriction to suffocate their prey.

Sense Organs Some snakes have heat- detecting pits below their eyes, to detect warm prey. Some snakes have heat- detecting pits below their eyes, to detect warm prey. Snakes and lizards flick their tongue to sense chemical molecules in the air. Snakes and lizards flick their tongue to sense chemical molecules in the air. They then pull the tongue into the mouth and insert it into a structure call the Jacobson’s organ. They then pull the tongue into the mouth and insert it into a structure call the Jacobson’s organ. This organ performs a chemical analysis of the molecules that are on the tongue This organ performs a chemical analysis of the molecules that are on the tongue This image shows the Jacobson’s organ.