Conservative Evolution

    Conservative evolution (CE) is the biological concept that once nature selects for a system that seems advantageous, one is able to see that advantage being utilized in other species.  For example, one can identify cilia being used in K. Protista with the Ciliates and also find cilia being used in K. Anamalia, P. Chordata Homo sapiens’ respiratory tract.  Another example is receptor-mediated behavior (RMB).  One may find Hydra’s using this in its feeding response (a simple behavior) but also find RMB being used by humans in the neurotransmitters that flow between a neuron’s synapse. Remeber, the definition of the word 'conservative' means something that is unchanging over time.

 As a review, the key points about CE is that

Evolution (in general)
     In general, evolution is random and blind.  It doesn’t strive to create a better living organism. Instead, random, chance happenings will somehow modify an organism.  Some modification(s) are beneficial, some have no effect, but most are bad.  Lets look at each type of modification.
    The “bad” ones usually die off so we never see or find them in nature.  By bad we mean modifications that do not confer some sort of benefit to the organism.  In fact, these modifications make it more likely they the organism will NOT be able to leave more descendants or even make them harder to find food and thus live.  As such, these organism cease to be left around in the gene pool and we don’t see them. Most modifications fall into this category.
    Some modifications simply neither exert a noticeable advantage nor disadvantages to an organism.  These modifications can just linger in the gene pool being passed on.  Maybe, with enough time, environmental conditions could change in the future and make these modifications advantageous. Or vice versa. But at the time that these modifications come about, they exert no noticeable effect.
    Some modifications are beneficial.  By this we mean that some modifications may confer some advantage to the living and reproduction strategies of an organism.  For example, maybe a modification of a structure allows an organism to exploit a new niche or environment where no others are present. This means the organism suddenly has no competition and is now able to leave more descendants. Thus, the modification seems beneficial.
    A last point about evolution to keep in mind is that all things alive are said to be perfect.  From the definitions of evolution, those organisms that alive presently are “perfectly” suited for their environment.  So, an organism from P. Porifera is at a level of perfection on par with humans.  Their current environmental niche allows them the ability to live and leave descendants.
Remember, evolution does “seek” to create perfection.  It randomly and blindly creates modifications.