What purpose do weeds serve in our eco-world?

Question

They must have some reason to be here, right? I mean like rats, we don't like em but they do serve a purpose. They are part of the food chain.

Answer 1

Weed is any plant a person considers an annoyance.  In other words, there is no such thing, because people seldom agree on what plant is a weed.

Plants serve are great purpose.  If it were not for plants, there may not be a human race.

Answer 2

<<They must have some reason to be here, right?>>

Apart from making new weeds, no, they don't need to serve a purpose and don't need to have any reason at all.

Weeds, being a wide variety of plants united by the characteristic of growing in places that gardeners or farmers don't want them to grow, are part of food chains.  They provide homes to various creepy-crawlies and squiggly things, and can get broken down as compost.  Those are potential uses not purposes, as the weeds aren't trying to provide those services.

Answer 3

Tell me again how Creeping Charlie growing through all my fencing, strangling my rose bushes and choking the fins of my central air unit is just a 'lovely plant in the wrong place'.  The only 'chaos' I have is the state of my yards and the value of my property.

Answer 4

As a botanist I have to point out that there is no such thing as a weed. Maybe an unwanted plant. Every species serves its purpose whether it provides necter for birds and insects, or it's seeds feed some other type of animal. Also, all vegetation serves a purpose for nutrient uptake and soil retenation. Without plants or "weeds" there would be an over abundance of nutrients in the soil causing it to change its compostion...or CHAOS!