Question

What are some of the groups (classes of Vertebrates) and what are significant characteristics?

Answer 1

Five major groups:

1. Amphibians
2. Reptiles
3. Birds
4. Fishes
5. Mammals

Amphibians

• They're cold-blooded animals
• They undergo metamorphosis
• Fertilization is external and happens in water
• They have a three chambered heart
• They can breathe through lungs and skins
• Need frequent access to water/moisture

Reptiles

• They are cold-blooded animals
• They lay eggs (oviparous) after internal fertilization
• They have a three chambered heart, except crocodilians which have a four chambered heart
• Breathing is almost exclusively through lungs
• Some reptiles have scales made of keratin
• Except snakes, all have four limbs
• Except a couple lizard species, they are all carnivorous

Birds

• Warm-blooded animals
• They have a four chambered heart
• They have limbs modified to work as wings which they use for flight, but there are some flightless bird species
• They are covered by feathers made of keratin
• Their bones are hollow which make them less dense and easier to fly
• They excrete uric acid
• Paternal behaviour is present
• They are always oviparous; fertilization is internal

Fishes

• Two chambered hearts
• Cold-blooded
• Streamlined body adapted to move through water efficiency
• They are either bony or cartilaginous
• They breathe with gills and use fins for locomotion
• Fertilization is external
• Many fish species are covered with scales

Mammals

• Warm-blooded, body often covered with fur for thermoregulation
• Mammals are both terrestrial and aquatic
• Mostly viviparous, but some mammals like platypus and echidna lay eggs
• Fertilization is always internal
• Sexual dimorphism is more noticeable
• Typically have four limbs with a variable number of digits
• Respiration through lungs
• Excrete urea
• Four chambered heart