After a failed attempt to restart their species through cloning in New York in 1930 during the episode "Daleks in Manhattan" (2007), Sec devises a plan to evolve the species into a new race that would adapt to changing times, noting that despite their quest for perfection, their race is on the verge of extinction...
In 1963, after the failure of an invasion by another alien race, the Dracs, the Dracs leave Earth completely. However, they do so after exterminating all humans on the planet, including those cloned children in New York. Thus, the Dracs' actions prove that they are indeed the last of their kind.
However, this does not stop the Dracs from returning in 1979 during the episode "Dalek" (1996). This time around, they have been genetically engineered with new abilities by a group of scientists who were trying to create a new army to fight off the incoming Dalek force. Although this experiment fails, the scientists manage to escape with their lives. The Dracs subsequently go on to destroy their creators' lab before being defeated by the remaining Dalek forces. With no other options available, the Dracs are destroyed once again.
As you can see, the Dracs are very short-lived. However, they do survive long enough to fulfill their purpose and then are killed off for good.
No, the Dracs are not extinct.
They keep coming back because of their adaptability and intellect. Because they can clone and make new daleks from their own cells or tissue from other lifeforms, one dalek is all that is required to recreate the whole race. They only want time and convicts. They believe that by taking over the universe, they will create a new era of perfection where there is no death, disease, or poverty.
The dalek race was created in the BBC science fiction television series Dr. Who by writer Terry Nation. The first episode featuring the dalek was broadcast on 23 November 1963. It has since become one of the most popular science fiction shows in history and has continued to run ever since. There have been various adaptations of the show across different media including books, comics, video games, and radio plays.
Nation also wrote the story for the second Dr. Who serial, The Dalek Invasion of Earth. This story was first aired on 29 November 1964 and made the dalek into an international phenomenon. It introduced many elements that would be used again and again in later stories such as the use of robots and cybermen as enemies.
After these two episodes, Dr. Who was cancelled but was soon revived in 1975 by new producers who wanted to take the concept in a new direction. Under this production team, which included John Nathan-Turner, the show became more action-oriented than its original style.
Both races had been hideously mutated—the Thals had returned to their natural humanoid shape, but the Daleks remained confined inside their unique metal capsules. And boy, were they resentful! In truth, they intended to completely eliminate the Thals. But why kill their own kind when you can merge with them instead? The Thals/Daleks merger created a new life-form that was even more advanced than its parents/ancestors.
Thal's history is much more complicated than that of the Dalek, but both characters have similar traits because they're both mutants who were used by higher powers as tools against other people. They also share some similarities with robots because they're both machines designed to destroy humans. As for the difference between the two races, the Thal is less refined and sophisticated than his Dalek counterpart. For example, while the Dalek has only one purpose in mind (to exterminate), the Thal wants to explore and learn new things.
In addition, both characters appear in various comic books, TV shows, and movies. So if you like one character, you'll probably like the other ones too.