omega 616 said:
If animals eat the weakest or an abnormal baby did these evolutions occur? Surely the mother would have seen the mutation and eaten it.
If I made a new animal, which had no defence or offense, then plonked it down in the animals version of hells kitchen (Aus) how would it evolve and adapt to the enviroment? If it gets eaten then it can't send a message to it's kids saying "evolve a way to stop being eaten. It sucks!", so how does it over many generations evolve the ability or a way to stop it'self being food?
If the first paragraph above were true, then there would be no evolution. To my knowledge it is not.
That isn't how evolution works. You take an existing animal and nature keeps killing off the members of its species that are the worst at surviving. The result is that ones with traits which are better suited to the environment live and give those traits to their children.
I'm not sure where you got this idea of evolution, but it isn't good. If my explanation isn't good enough, I suggest you find some entry level text and read that.
I just don't buy it... look at the complexities of a human heart and explain to me how natural selection and random genetic mutations created such a perfect organ. Chiefly, explain to me how come "evolution" chose such a complex mechanism when a whole host of other systems could work. Every loop, crevis, nook, cranny, detail (both large and small) has a unique purpose in the heart. Not to mention over a single individuals life the heart "evolves". The heart of a fetus is RADICALLY different from the heart of an adult... How does that spring up from natural selection? I sincerely makes about as much sense to me as my creamy mashed potatoes spontaneously covering themselves with butter, gravy, pepper, and salt... and then giving me the steak and broccoli too.
It's not necessarily that I believe in anything else, I just don't understand how this could happen.
I guess life's a miracle... but aren't miracles from God? hmmm...............
Actually, if you look at the hearts of animals of different levels of complexity, you'll see something interesting: The hearts gradually move from very simple balls of muscle around a vein to the more complex hearts we mammals have today:
In insects you have an open system with (several/a) heart(s) that has only one "chamber".
The blood moves into the heart, which contracts and squeezes it out into the arteries, which in turn empty the blood into the body of the insect.
Then look at the common earthworm: It has a closed system, so the arteries do not empty the blood into its body. Its hearts are similar to those of insects. They consist of merely one chamber which blood enters. The chamber then contracts in otder to push the blood through its arteries.
Then look at fish; the next step in complexity: The fish's heart is divided into two chambers. The blood moves into one chamber, and is then let into the other which squeezes the blood trough the system.
Then you have amphibians: Their hearts are divided into three chambers. Blood enters the right pre-chamber, then it moves into the large third chamber, which squeezes the blood out towards the lungs, where it picks up oxygen. Then the blood enters the left pre-chamber, then again passes into the large third chamber, and is squeezed out into the body.
The problem with this system is that the oxygen-saturated blood is to some degree mixed with the oxygen-less blood in the third chamber. Thus the amphibian is not able to use the oxygen in the air very effectively.
Wouldn't it be nice if the third chamber was separated into two chambers just like it is with us mammals, so that it could be more effective?
Yes, and that's the interesting part. Let's look at the animals that are slightly more advanced than amphibians: Reptiles
The hearts of reptiles work in the exact same way as those of amphibians, except for one little detail: There is an incomplete wall separating the two halves of the third chamber.
This means that reptiles can better utilize the oxygen in their blood (and grow larger).
The most advanced animals are birds and mammals. These have hearts with four chambers (the workings of which I presume you understand already) that allow them to make the best use of the oxygen in their blood.
Take a look at this: http://en.wikipedia.org/wiki/Circulatory_system#Nonhuman
Looking at it like this, it becomes very obvious that our hearts have probably evolved from a simpler form to reach the form they have in this day.
As for why evolution chose that system when there could be better, more effective alternatives. This would be because evolution, is not
a conscious thinking being. It doesn't choose what is best, it merely chooses in favour of what works
Indeed, the fact that we aren't perfect suggests that we weren't made by a creator, but rather by a process in which the ones who are the best adapted survive and reproduce.