This week I have learned about Primary and Secondary succession. Primary succession first starts when a glacier exposes bare rock where nothing lives. Then lichen started to grow on these bare rocks the acid from the lichen began to break down the rock into particles. The particles and dead lichen mixed together and started to create soil.  Since lichen is the first species to live on the bare rocks they are considered pioneer species. After the dead lichen and bare rock have created soil then there are roots. After many years the roots are deep enough to create moss and the moss will replace the lichen one day. Insects make moss and lichen their home and when the insect dies they repurpose into the soil. After a few years, the soil begins to thicken and the moss is replaced by ferns. Sometimes ferns can be replaced by wildflowers. In the last stage after hundreds or maybe thousands of years, the soil might be stabilized enough to support an entire forest. In Secondary succession, the first stage is when someone stops mowing their lawn or when a farmer stops growing crops. Then weeds start to form and the most common or popular weed is crabgrass. It’s normally the first weed to grow during the year. In the second year of Secondary succession, the lawn or field is really weedy. Because the wind could have spread the seeds or insects could have transported them. The most popular weed during this time is horseweed.  After the second stage from 5 to 15 years, small pine trees begin to develop and it will continue to grow for almost 100 years. The last stage is when pine trees begin to die, then they are eventually replaced by hardwoods if the temperature can stabilize them.