Check out the ocean.
Then you see things like sponges (a group of similar cells) with other unattached cells aiding them in their own and the sponges' survival.
Sponges are animals
Then you see a more complex being with organs involved in an entire system (digestive, muscular, nerves).
(Now for the eye, some organisms start getting cells that detect whether or not there is light. Then some get eyespots. Then you see even things like lobsters with cool eyes, and bugs. Then fish, and frogs, but not plants. Why not plants? Why not ask yourself that, and try to actually learn something?)
Then a line of nerves is seen down a certain side of the organsim called a notochord.
(We are starting to see creatures on land evolve other adaptations, like exoskeletons-bugs, instead of these vertebrate inner bone structures, but that is a different story from this one).
Then you see others more complex with a backbone. Hello vertebrates! Think of a shark or any bony fish here. They have actual mouths, gills, etc. Look how long it took to get to this point! It took over 3 billion years! Look it up.
Limbs appear as some fish make forays onto land to get out of a puddle and back into a large body of water.
An organism first makes its way on land after spending the first part of its life in water (ribbit!)
Then eggs get laid as the being starts out as an air breather-reptile instead of a tadpole. They got bigger and more complex, but cold blooded Reptiles!!
(dinosaurs/reptiles cannot function when they are cold, and they would warm up slowly with those big bodies, they may starve before they become warm enough, then mobile enough to get food).
The earth is cooling. The dinosaurs are sluggish, something may have cratered into the earth, and warm blooded creatures take over the environments left uninhabited by dwindling reptiles.
The first mammals appear, laying egss (monotremes).
Then marsupials are the first to have their offspring start out inside their bodies.
Another mechanism is a uterus instead of an egg staying in the reproductive tract, and the placentals are roaming around.
Along lines of placental mammals you see splits, like into canines, felines, and primates.
Eventually, the primate line branches with apes evolving on one, and hominids on another. Separate, but with a common ancestor at the base of the branches.
Now, tell me this all does not make any sense!
Similar things happen with the botanicals, starting out as things in the water with chlorophyll instead of ingesting each other. Using the sun's energy instead of having to eat.
Now, along with other posts about the many evolutions of the eye, etc....are we learning ANYthing JF??
I have this HUGE biology book sitting in front of me as I write this. Did they start out with prokaryotes?? No, they start out with how a single cell, any cell works. Do you even know the difference between meiosis and mitosis? Do you know the difference between bacterium and viruses? Do you CARE??
Will you ask one single intelligent question by now, please demonstrate you tried to learn SOMETHING, pleeease.