Lugbzurg said:
Let's look at a few things. One moment, Evolution says that little cells slowly evolved into complex lifeforms. Next, it says that these complex lifeforms start devolving into simpler lifeforms.
You can't have a slowly-developing heart, brain, lung or any of that. There are several important parts that must all be there right from the get-go, or the creature will die.
Considering that these lifeforms are supposed to evolve into some better creature, how is it at all likely that two lifeforms could end up being compatible after evolution has taken place for any number of generations?
I'd recommend looking up Incredible Creatures that Defy Evolution. There's blatant proof that there is indeed a grand creator. You've just gotta pay attention, putting two and two together. Then, it becomes obvious.
Evolution says neither of those things. It is not a 1 way street but an undefinable number of branching paths that go back and forth. Evolution doesn't (or at least hasn't) retraced it's steps, so the concept of devolution is silly. Any apparent regression is in response to changes in the environment (access to food supplies gets harder, means predator size and methods MAY change for better conservation and potency).
We don't evolve in the sense of increasing superiority, but as a natural form of equilibrium. It's not that hard to grasp. Apex predators over feed? Prey dies out or diminishes, food supplies drop and given enough time, the predator may evolve to adjust to the new conditions (for example, they get smaller in size to better conserve the precious energy). Conversely, an abundance of food or a spike in numbers of prey means the predator feeds more. Given time the excess food can result in changes that make use of the increased food supply, rather then let it go to waste.
Evolution adapts to the environment (which includes things like weather, temprature, presence of certain minerals/elements, and the presence/quantities of food). It doesn't spontaneously occur for no reason. The mutations that result in evolutionary steps or leaps are more haphazard, given the astronomical number of variables that can affect change at a genetic level.
As for the necessity of major organs to just exist, look at the simpler life forms on our planet. The Earthworm doesn't have a conventional brain:
""Brain". The earthworm's brain is made up of paired ganglia (group of nerve cells) connected to a nerve cord. An impulse, such as touch, light, or moisture, is detected by skin cells." This is, essentially, a basic brain. It controls only a few simple senses, but no sound, sight or smell.
It only has a linear circulatory system:
"Circulation. In worm biology, there is not one heart, but five pairs of aortic arches, which function like a human heart. They are responsible for pumping blood into the dorsal and ventral blood vessels." The Worms "heart", much like the brain, is incredibly simple. While the human heart pumps blood around miles and miles of arteries and veins with powerful muscles, the worm heart simply keeps the blood flowing in a 2 directions, to the front and to the back.
And lastly, you'll love this one, the lungs... it doesn't have any either.
"Respiration: In worm biology, there are no lungs, but a thin layer of moist cells through which oxygen diffuses in and carbon dioxide diffuses out. These molecules must be wet so that they can enter and exit the plasma membrane, thus the worm's requirement for a moist environment. "
With this one mundane animal, I have shown a basic brain, a primal circulatory system and the complete absence of lungs, though still retaining a biological function similar to breathing.
To add to this, look at amphibians. They have water lungs, capable of diffusing oxygen from air and water, with not particularly noteworthy efficiency over gills or air only lungs.
Finally, I recommend you research Jellyfish. If they aren't existing perfectly fine without certain "necessary" organs, they are using a very primitive equivalent in its place.