ECOLOGICAL SUCCESSION is the series of changes that a particular ecosystem undergoes over a particular period of time. Ecological succession can be of two types viz: primary succession and secondary succession.
Primary succession is a type of ecological succession that involves the colonization of a barren area of land with no soil i.e. no pre-existing organisms. The barren area consists of bare rocks and surfaces that are colonized by organisms like LICHENS for the first time. These organisms are called PIONEER.
The lichens act on the bare rocks by secreting chemicals that help degrade the rock particles to form soil, which paves way for other organisms like plants to grow.
En biología celular, el núcleo (pl. Núcleos; del latín nucleus o nuculeus, que significa núcleo o semilla) es un orgánulo unido a la membrana que se encuentra en las células eucariotas.