• Question: Plants are pretty and they provide oxygen and remove carbon dioxide, is there any other reason they are here?

    Asked by wookiee to Amelia, Clem, Izzy, Sarah on 13 Mar 2014.
    • Photo: Isabel Webb

      Isabel Webb answered on 13 Mar 2014:

      Plants are on the Earth for the same reason that humans are on the Earth – they evolved that way. Each species exists because it found a strategy to help to survive, and so now is there.
      Plants evolved to use water and carbon dioxide to make food – and the production of oxygen is just a side-effect of this (not a reason that they are here). The way that they live lets them survive on Earth, and so unless they run out of resources and die, plants will stay living here. Evolution has no ‘right answer’ – things evolve and survive, and if they can’t survive go extinct.

      There are other reasons that plants are good though, other than making oxygen. Plants take up water from their roots and then excess water leaves the plant through the leaves into the atmosphere – so plants contribute to the water cycle. Without this the air would have much less water vapour in it, and so this would mean more water in seas and lakes and probably floods everywhere – humans may not have survived if this were the case.
      Plants also are at the bottom of every food chain. Plants make their own food, but animals cannot – so we rely on plants to provide us with food, or provide food for the animals we eat. So without plants, we might not have enough food to live.
      Plants also provide useful materials – imagine a world without wood or paper! Or a world without silk or cotton. Lots of medicines come from plants, and other chemicals such as pigments used as colours and dyes. There is lots of research being done on ‘natural products’ from plants and how we could improve them.

    • Photo: Amelia Frizell-Armitage

      Amelia Frizell-Armitage answered on 13 Mar 2014:

      Plants are vital for us to survive. You are quite right in saying that they put oxygen into the air and take carbon dioxide away. This is probably one of the most important things as without this we wouldn’t be able to breath. However, there are so many other reasons that plants are incredibly important – too many to write in the answer in fact. I’ll list a few here:

      Plants provide us with all the food we eat. If you are a vegetarian you ONLY eat plants. If you are a meat eater the animals you eat get fed on plants.

      Plants provide us with a lot of materials to make the things we use such as paper, and wood. we wouldn’t have these things if it weren’t for plants and trees. Other materials from plants include rubber, some plastics and dye. Try to imagine life without any of these things and you’ll find that a lot of what you own is made from plants!

      The roots of plants, especially tall trees, are important for holding together the soil. If the soil crumbled and fell apart we would have nothing to walk on!

      Plants provide us with medicine.

      Plants can be used as fuel. This is more important than ever now as we are running out of other fuels like oil for petrol! We need to find a way to keep powering our cars and homes when the oil has run out and plants could be the answer!

      Some types of plant can be used to clean water to make it safe for us to drink.

    • Photo: Clemence Bonnot

      Clemence Bonnot answered on 13 Mar 2014:

      Plants are a type of organism that evolved from the common ancestor of all earth organism… Yes we do share common ancestors with plants 🙂 The reason they are still here is that they as well as us are adapted to various environment and have found a place in our ecosystems (have food, have predators, enter in the food chain). ecosystem are fragile equilibrium and a non adapted organism will disappears. If it as no predators if over spread and exhaust all its resources and disappear or evolved to adapt to the new situation (but the original organism still disappear), if it has not enough defenses it is killed….
      Plant in fact are some of the most adapted organism call they only depend on themselves for food (with some exceptions for some plants) and produce their energy from the sun. they produce and use both oxygen and carbon dioxide… Not like animal that relies on plant to survive. cause carnivorous eat carnivorous or herbivorous and herbivorous eat plants!
      Plant could survive without animals ( not all but some, enough to create a new diversity) , no animals would survive without plants…

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