Question

Amphibians were the first tetrapods, list all of the evolutionary milestones that first appear in amphibians. Describe in depth ways amphibians are similar to boney fish.

Answer 1

The amphibians are the first first vertebrate group to develop the limbs and are able to be on the land.amphibiaqns shows wide range of the survival stratagies.The amphibians of the current state like the mammals birds and the reptiles come s under the super class "TETRAPODA" which means having four limbs.These are believed to be evolved around 395 million years ago in the denovian period and are a transition from the lobe finned fishes named as sarcoptegians in which we will find the current lung fishes.

And this group of fishes most charecteristic feature is by their fins nad they formed a bony base and subsequently transformed into the tetrapods.

HOW DID THEY CHANGE TO LIVE ON LAND (Their adaptations) :

• Here are some most important adaptations which made tham slowly update themselves to leave water and get adapted on the land.
• The evolution of lungs which are the homlologous organs to gas bladder in the fishes which helps the fish for the buyoncy.first they appered as an additional feature in some sarcoptegians as some of them used to live in waters with low oxygen content and so by this evoultion of lungs they are able to take oxygen from air rather than which is dissolved in water.
• Development of internal nostrils which are also known as "CHOANAES"generally fishes have two external nostrils through which water passes through where as these have only one nostril which is connected to the internal nostrils and in communication with its mouth.
• development of quirdium like limb :It is the most basic charecteristic of tetrapods.having the parts like stylopodium(one bone either tibia or fibula)Zeugopodium (having two bones like radius or ulna,tibiaor fibula)Autopodium(comprise fingers or toes containing meta carpels or tarsals and the falanges.
• SIMILARITIES BETWEEN AMPHIBIANS AND FISHES:
• Both of them lays eggs.
• they both are exothermic (cold blooded animals)
• Both have stream lined body.
• Both have fins.