Why Chordate are Advanced than Nonchordate 

If we study carefully then we will find that some features of chordate are advanced which gives them some advantages over non-chordate animals and if we look at the evolutionary timeline then we will find that chordate evolved from non-chordate.

During evolution, some special advanced characteristics arise in some non-chordate which makes them superior to others non-chordate, and with time a lineage of non-chordates gives rise to Chordate.

It is true that some non-chordate are prominent yet than some groups of chordates but if we think about their advanced characteristics then chordates have more advantages over non-chordate and now we will discuss those features which give the chordate an advantage over non-chordate.  

Advanced Features of Chordata over Nonchordate: 

Advanced Nervous System and Sensory Organ:

In animals, very fast coordination between different parts of the body (inside body) is only possible when the nervous system is well developed and the sensory organs are aware of the animals to the external environment.

The animal can adapt themselves in the right direction only when they have advanced sensory organs and if we notice the evolution of the nervous system and sensory organs from lower non-chordate to higher non-chordate then we will observe a gradual advancement.

This advancement over time gives rise to a well-organized central nervous system and sensory organs in higher non-chordate and Chordate and a centralized nervous system makes the Chordate superior over other animals.

The centralized nervous system and sensory organs make the Chordate aware of its environment quickly and it helps them to adapt themselves in almost all types of environmental conditions.  

Endoskeleton:

In most of the non-chordate living, the endoskeleton is absent, instead of the endoskeleton they generally have a non-living exoskeleton which is shed over time.

But in the case of chordate most of the animals process living endoskeleton which can grow over time and help their animals in movement and give much more mechanical support.

The endoskeleton in Chordata help to grow in size and they can move more swiftly and due to this growing endoskeleton, we can see much bigger Chordata than the size of non-chordate.  

More Efficient Respiration:

The mode of respiration in most of the non-chordate is not very efficient and faster, for example, general surface area in case of some animals and trace in case of arthropods are suitable for the small animals but in the case of higher animals, those modes of respiration are not best.

In most of the chordate advanced respiratory organs lungs are present which helps the animals to respire more effectively and faster rate.

In the case of aquatic animals like fishes, some amphibians larvae process gill which is also an efficient respiratory organ and helps the aquatic animals to take oxygen dissolved in water and pass out the carbon dioxide into water.

With the help of lungs and gill animals increase the respiratory surface area and it helps in faster gaseous exchange and faster gaseous exchange enables them to fasten their metabolic reaction in a faster way.  

Efficient Circulatory System:

Faster respiration is worthy only when the animals have an advanced and efficient circulatory system because the oxygen reaches up from cell to cell through the circulatory system and an advanced circulatory system helps the animals to fasten their metabolic activity.

If oxygen supply does not occur at a faster rate then the metabolic activity will slow down if the excretory material removal process does not occur fast then the accumulation of excretory material can cause a slow down of metabolic activity and for this reason, an animal needs efficient circulatory system.

In chordate the advanced blood vascular system help in faster circulation of different required materials and make them superior over other groups of animals. 

Reference: Why Chordate are Advanced than Nonchordate