Think about fish, ants, dogs, cats and people.  What do they have in common?  They are all animals!  Animals come in all kinds of different shapes and sizes.  Believe it or not, plants come in all kinds of different shapes and sizes too.  Plants are not always green, bushy, and full of leaves.

There are many different kinds of plants and animals, but they all have one thing in common: they all need water.  However, have you ever wondered if a plant needs to eat?  Like all living things, plants need food.  You never see a plant with a sandwich though!  That's because many plants are able to make their own food.  Imagine being able to make your own food.  You would sure save a lot of time and trips to the grocery store.  Plants are autotrophs, which means that they can make food for themselves using chemical energy or energy from the sun.

Just like animals, plants live in many types of places.  If you walk by the water, you might notice what looks like a thin green carpet.  This carpet is made up of moss -- a small, soft plant that grows in shady areas.  Moss like to live by the water because they don't have big roots to bring water up from underground to their different parts.  Instead, they use their tiny stems to take in water from the air around them.  Plants like moss that don't have roots or tubes to carry water are called simple plants.

No roots, no problem.

All simple plants need to live by the water because they are not able to carry water themselves.  Instead of having tubes inside to carry water, simple plants need water brought to them.  Green algae are a group of single-celled simple plants.  They are very important because they take in more energy from the sun and make more oxygen than all other plants put together.  Algae are interesting, but do not be fooled: simple plants are very simple!  Not only do they not have roots, they also don't have leaves.

I may be simple but I make more oxygen than everyone else.

So far we have only heard about simple plants living by the water.  But there are more complicated plants that live by the water too.  Ferns are related to moss and were the first plants in the history of plants to have leaves.  They use their leaves to get energy from the sun, which they then turn into food.  Ferns are different from simple plants because they have roots and leaves.  They mostly live by the water, but some are able to live away from the water because of their roots.  They have parts that work like pipes, helping to store and spread out water.

I was number one!

Ferns, algae, and moss are all able to make their own food from the sun's energy.  They all live by water, but there are differences in the way they get water.  Plants come in all different shapes and sizes.  Next time you are outside, look around and notice the many kinds of plants around you.