Vertebrates
Vertebrates - Back boned animals:
Not only vertebrates are back boned animals because vertebrata is not the phylum of back boned animals. Chordata is the phylum of back boned animals and vertebrata is the sub-phylum of chordata. Here, back bone is generally considered as notochord. This notochord is strong and rigid to give good support to chordate animals. But in vertebrates, it was modified as jointed backbone which is called as 'vertebrae'. Animals those possess vertebrae is called as vertebrates.
Modern and major classification of vertebrates:
As per the modern day of classification, there are only five classes of vertebrates. They are
- Pisces (Fishes)
- Amphibia (Amphibians such as Frogs and toads,etc.)
- Reptilia (Crocodiles, snakes, Dinosaurs, turtles, etc.)
- Aves (All birds including penguins & excluding bats, etc.)
- Mammalia (Rats, Rabbits, Elephants, Whales, Bats, Human beings, etc.)
Pisces - Aquatic animals:
Pisces is the class where all aquatic animals such as fishes excluding dolphins, whales and some aquatic amphibians and reptiles. Fishes originate in the Devonian period which is considered as the "Age of fishes". Fishes again classified into:
- Agnatha (Jawless fishes)
- Chondrichthyes (Cartilaginous fishes such as shark, ray, etc.)
- Osteichthyes (Bony fishes such as Catfish, Tilapia, Carps, etc.)
We can see that very common adaptation acquired by fishes for aquatic life. They are
- Streamlined body,
- Gills for respiring dissolved oxygen in water,
- Fins present at suitable places for effective swimming.
Amphibians - Animals evolved from water to land:
It is believed that the amphibians evolved from labyrinthodonts which are the transitional animal group between fish and amphibians. The most familiar animals found in amphibians are frogs and toads, etc.
The adaptation acquired by amphibians is:
- Cutaneous respiration when the animals found inside the water,
- Nictitating membrane found in the eye to get clear view inside the water.
- Webbed foot to give effective swimming.
Reptiles - Amazing animals:
Yes, reptiles are very amazing because the size range of animals also very amazing, as it ranges from very small lizard to huge dinosaurs. You can see variety of adaptations in this group because it habituated in water, in land, in damps, in deserts, etc.
Birds - Aerial animals:
Even in invertebrates, insects exhibit flight, but the birds shows exact flight adaptation, that's why it is very perfect aerial animals. The flight adaptations are:
- Reduced bone marrow to reduce bone weight.
- Pored bones
- Air sacs,
- Bursa of fabricius,
- Feathers & wings, etc.
Mammals - Milk feeding animals:
The striking characteristic of mammals is feeding milk to their young ones. Based on their habits and adaptations, it is diverged into various groups such as
- Burrowing rats and moles,
- Flying bats,
- Fast running cheetahs,
- Long leaping kangaroo,
- Aquatic whales and dolphins, etc.
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