The evidence for the one designer scenario are mainly these:
1) Signatures (dna etc): all living organisms require dna & or rna to determine their distinguishing features, live and adapt....Including rna viruses. Imagine taking away dna from every living thing....what organisms will these kinds of viruses be left with to reproduce & survive?
2) Noticed similarities (common design): Everything requires mechanisms to utilize water & or sunlight to live.
3) The intricacy of the ecosystem: All Organisms depend upon each other to both regulate the environment in which they live and survive.
I'm having trouble seeing how any/all of these negate multiple designers.
As for #1: if DNA is a signature, since we know there are at least three different structures for DNA does this evidence three designers?
For #2: I fail to see how the fact that most cars have wheels, lights, windshields, engines, seats and radios equates to there only being one designer of cars. Isn't similarity of design rather than exact replication of design a hallmark of additional designers?
#3: This seems to me to have PCC (Project Coordinating Committee) written all over it. How does the complexity and intricate interweaving of an ecosystem evidence one designer over a coordinated effort of many?
Would you elaborate on these for me please?