Vertebrates

Vertebrates are a large group of chordates (animals with backbones) that includes mammals, birds, reptiles, amphibians, and fish. They are characterized by having a vertebral column, or backbone, and a complex nervous system that includes a brain and spinal cord.

Characteristics

Vertebrates are distinguished by their vertebral column, or backbone, which supports the body and encloses the spinal cord. The backbone is made up of a series of vertebrae, each of which is a complex structure that protects the spinal cord and provides attachment points for muscles.

Vertebrates also have a well-developed nervous system, which includes a brain and spinal cord. The brain is responsible for coordinating the body's activities, while the spinal cord transmits signals between the brain and the rest of the body.

Classification

Vertebrates are classified into five main groups:

• Mammals: These are warm-blooded vertebrates that have hair or fur and produce milk to feed their young. Examples include humans, dogs, and whales.
• Birds: These are warm-blooded vertebrates that have feathers, lay hard-shelled eggs, and have a high metabolic rate. Examples include eagles, penguins, and sparrows.
• Reptiles: These are cold-blooded vertebrates that have scales or scutes and lay soft-shelled eggs. Examples include snakes, turtles, and crocodiles.
• Amphibians: These are cold-blooded vertebrates that spend part of their lives in water and part on land. They have smooth, moist skin and lay eggs in water. Examples include frogs, salamanders, and newts.
• Fish: These are cold-blooded vertebrates that live in water and have gills for breathing. They have scales and lay eggs in water. Examples include sharks, salmon, and seahorses.

Evolution

The first vertebrates appeared during the Cambrian explosion, about 540 million years ago. These early vertebrates were small, soft-bodied creatures with simple backbones. Over time, vertebrates evolved into a wide variety of forms, from tiny hummingbirds to massive blue whales.

See also

• Invertebrates
• Animal classification
• Evolution of vertebrates

References

Vertebrates Resources
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