Definition and Characteristics
Reptiles are a class of vertebrates known for their scaly skin, which helps prevent water loss. Unlike amphibians, they do not require water for reproduction; most lay eggs with hard shells. Reptiles are ectothermic, or cold-blooded, meaning their body temperature is regulated by external environmental conditions. They breathe air through lungs, even those species that live in aquatic environments.
- Reptiles have scaly skin, which prevents water loss.
- Most lay eggs with hard shells, unlike amphibians.
- They are ectothermic, regulating body temperature externally.
- All breathe air through lungs.
Importance in Ecosystems
Reptiles play significant roles in ecosystems as both predators and prey, helping maintain balanced food webs. They contribute to the control of insect populations and are essential for rodent and rabbit management in many habitats. Additionally, reptiles such as turtles and crocodiles help shape their environments; for example, turtles create ponds that provide habitats for other species. Their waste and death contribute to soil fertility, making them vital in nutrient cycling.
- Reptiles are key predators and prey in food webs.
- Control insect and small mammal populations.
- Alter environments, such as turtles creating ponds.
- Their waste and decomposition enrich soil, aiding nutrient cycling.
Reptile Anatomy
Reptile anatomy is specialized for their terrestrial lifestyles, although some have adapted to aquatic environments. Key features include:
- Skeletal System: Reptiles have a strong bony skeleton with a backbone, providing support and protection for internal organs.
- Skin: Covered in scales made of keratin, reptile skin is waterproof, reducing moisture loss and helping them thrive in dry environments.
- Limbs: Most reptiles have four limbs (except snakes, which evolved from limbed ancestors), adapted for walking, climbing, or swimming.
- Respiratory System: All reptiles have lungs; even those that live in water, like some turtles, breathe air.
- Circulatory System: Reptiles have a three-chambered heart (except crocodiles, which have a four-chambered heart), more efficient than amphibians, allowing better oxygenation of blood.