Main Characteristics and Types of Vertebrate Animals

Characteristics of Vertebrate Animals

All vertebrates have a characteristic in common: their bones and spine. There are five types of vertebrates:

Fish

• Spindle-shaped body.
• Skin covered with scales.
• Poikilotherms (cold-blooded).
• Breathing through gills.
• There are carnivores and others that are herbivores that feed on plankton.
• They reproduce sexually with external fertilization. Fertilization takes place in water. Eggs hatch into several small larvae called fingerlings.

Amphibians

• They have four limbs as legs.
• They have bare skin and need to be constantly wet.
• They are poikilotherms (their body temperature varies with the temperature outside). So, when they go into cold lethargy, it is a kind of deep sleep.
• Adults breathe through lungs and skin.
• Adults are carnivorous and hunt small invertebrates, which they swallow whole.
• They have sexual reproduction, and fertilization can be internal or external. The eggs develop in water, unlike on the mainland because they lack a dried shell. When the tadpoles hatch, they are larvae that live in water and breathe through gills. To become adults, they undergo metamorphosis.

Reptiles

• Except for ophidians (snakes), all the rest have four limbs and feet; only turtles have limbs that take the form of fins.
• They have the body covered with hard scales.
• They are poikilotherms.
• They use lungs to breathe.
• Most are carnivores and hunters.
• They have internal fertilization and sexual reproduction.
• The eggs are hard-shelled and must be incubated. The place of birth is on land.

Birds

• The shape of the beak is related to the diet of each bird.
• They have forelimbs transformed into wings to fly.
• They have skin covered with feathers, which prevents the loss of body heat.
• They are homeotherms (warm-blooded).
• They breathe through lungs.
• They have sexual reproduction and internal fertilization. The parents must incubate the eggs.

Mammals

• They have limbs as legs or wings.
• They have skin covered in hair. Females have mammary glands.
• They are homeotherms (the body temperature is regulated).
• They breathe through lungs.
• There are carnivores, herbivores, and omnivores.
• They have internal fertilization and sexual reproduction.

Classification of Vertebrates

• Fish: Bony (sardine, tuna, etc.) and cartilaginous (sharks and rays).
• Amphibians: Anura (frogs and toads) and Caudata (newts and salamanders).
• Reptiles: Testudines (turtles and tortoises), Crocodilians (crocodiles and alligators), Sauria (lizards, chameleons, and iguanas), and Ophidians (snakes).
• Birds: Flying birds (including ducks and chickens) and flightless birds (such as the ostrich).
• Mammals: Monotremes (oviparous, like the platypus), Marsupials (viviparous, like kangaroos), and Placentals (viviparous, like rats, hippos, and humans).