What is Life cycle?
{{multiple image |direction=vertical | | header = [[Endopterygota|Most insects]] go through sharply defined stages in their life cycle | width = 150 Dvd cutted.png | caption1 = Egg | image2 = Danaus plexippus caterpillar.jpg | caption2 = [[Caterpillar]] larva | image3 = Monarch Butterfly Cocoon 3.jpg | caption3 = [[Pupa]] | image4 = Danaus plexippus emerging from chrysalis 04.jpg | caption4 = Butterfly: [[imago|adult insect]] }} '''Life cycle''' means the stages a [[Organism|living thing]] goes through during its life. In some cases the process is slow, and the changes are gradual. Humans have various stages of growth during their lives, such as [[zygote]], [[embryo]], [[child]] and [[adult]]. The change from a child to an adult is slow and continuous. In many [[society|societies]] it is marked by ceremonies at [[puberty]]. In most [[insect]]s the transition is sharp and well-defined: [[ovum|egg]] > [[larva]] > [[pupa]] > [[imago]] (adult). == Different generations have different forms == In some animals, the parent generation looks different from the child. The most common case is that there are two different forms. One form will have [[sexual reproduction]], the others might not reproduce, or might reproduce [[asexual reproduction|asexually]]. Some plants and a few other organisms have a system called ''[[alternation of generations]]'' which is not quite the same because one form is [[haploid]] and the other is [[Diploid|dipoid]]. === Parasites === [[Parasitism|Parasites]] are organisms that benefit from harming other organisms. The organism they profit from is usually called [[Host (biology)|host]]. Many parasites have complex life cycles, where they need different hosts for different stages of their development. As an example, the cycle egg > [[snail]] host > [[mammal]] host is common for parasites of [[Herbivore|herbivorous]] mammals. [[Malaria]] is caused by single-celled parasites. These parasites go through two stages in their development. One stage is in the [[blood]] of [[mos