Tadabur Biology: Life Cycle

Everything has its life cycle. 
From this tiny bacteriophage.... 
[rather known as viruses that infect bacteria. Yes, viruses are a lot smaller than bacteria! They get into the bacteria, and reproduce, then when released, re-infect, re-produce again, and so on] [source]

To this Drosophila..... 
[what a fancy name. It's actually lalat buah[source]

And this beautiful creature butterfly...[source]

And us! [source]

Generally all of us have a similar life cycle.
It's a cycle so it should be the same la.
Aha, so what does make us different with those lalat-lalat and kuman-kuman?

You see, at least bacteriophage, Drosophila and butterfly have served their purposes of life before the end of each cycle. 
If you took Ecology or Organism Biology or Virology or Bacteriology or stuff like that, you might have learned their roles in this world. 
For example, 
bacteriophage is used for DNA sequencing.
You need virus to produce vaccine and bacteria to get anti-bacteria 
in order to fight flu or diseases. 
Drosophila is widely used for many researches especially in genetics.
(And you need butterfly to take pictures with together with flowers at Hyde Park because they are cute).
Ask Biologists, they know.

But truly He knows more than the Biologists do.

الَّذِينَ يَذْكُرُونَ اللَّهَ قِيَامًا وَقُعُودًا وَعَلَىٰ جُنُوبِهِمْ وَيَتَفَكَّرُونَ فِي خَلْقِ السَّمَاوَاتِ وَالْأَرْضِ رَبَّنَا مَا خَلَقْتَ 
هَٰذَا بَاطِلًا سُبْحَانَكَ فَقِنَا عَذَابَ النَّارِ
Who remember Allah while standing or sitting or [lying] on their sides and give thought to the creation of the heavens and the earth, [saying], "Our Lord, You did not create this aimlessly; exalted are You [above such a thing]; 
then protect us from the punishment of the Fire. Ali-Imran [3:192]

But then.......... 
how about us? Our roles? Our purposes of life? 
Do we really know why exactly are we created? 
Don't ask Biologists this time. Because the answer is already there. 

Watch this, and think. =) Tell me the answer if you got it.