Perfect is a closed circle, static, fulfilled, existing out of time. An idea that does not really happen in nature because of the need for change and adaption in order to survive.
Take an oak tree. Imagine for now it is born from the perfect acorn in the perfect soil, it has every potential of becoming the perfect mushroom shaped oak seen in picture books. It grows into a stalk, and starts to develop leaves, but there are big holly bushes next to it, so it’s leaves can’t get much sunlight to photosynthesise. It is going to have to grow much taller than them. In its 30th year there is a harsh winter, so it drops some of its lower branches to conserve nutrients. In its 50th year a house is built to one side of it preventing sunlight reaching it from that side, so to make up for this it grows more on the other side giving it a somewhat crooked shape. The tree is a healthy oak that will live for a couple of hundred years, but it is not the perfect tree, it does not have that neat mushroom shape, it is crooked, tall, and sparse on the lower branches. It is the ability to change and not remain perfect that has meant it can live a long healthy life.
Now we imagined a perfect acorn, but evolution being as it is, that acorn probably wasn’t perfect, a genetic difference may have slightly altered the tree’s bark, or made it extra tasty for a particular insect. While in one case this could have been an annoyance and potentially damaging to the tree, in another the bark difference could make it particularly resistant harsh winds, so if it or one of its future acorns ended up on the Scotland Highlands it would have a better chance of survival than one that didn’t have that bark difference. Equally so being tasty to a particular insect could be damaging in one instance but if that insect happened to eat another more deadly insect that could infect the tree then being tasty to the first would be an advantage.
That is just one simplified example of the need to adapt and how the our idea of the classical closed perfect organism would not survive because it can not change and adapt to its environment.
If you get a compass and draw a circle on a piece of paper it may look perfect, you can call it perfect and others will agree. Yet time will smudge and fade the ink, it will tear and rot the paper, till eventually your perfect circle is nothing but mush. This mush will hopefully be put in the ground where if can feed another seed which will eventually grow into another plant that will feed another animal or maybe even a human who draws another perfect circle.