Let's take a minute and classify you.  No, this will not hurt.  Let's see . . .  you are a person, right?  You belong to a group called "students."  You spend your day at school with other students.  Your school is filled with other people who are not students but help the students learn.  Did I get all that right?  It is very helpful to find out how a living thing fits into the world and how it changes the things around it.  By knowing what kind of human you are, I can probably tell when you wake up, what you study, what you eat at school, maybe even what you want to be when you grow up.  Here, I will show you how to do it.

It all begins with one living thing.  You are a person.  One organism.  Pick an animal.  I am going to guess you picked a . . .  slug.  No?  Maybe I do not know everything about you.  How about a bee?  An organism is one living thing.  It can be anything from a piece of grass to a chicken to a blue whale to you.  Think of it as one thing that needs energy to keep on living.  This is what makes an organism different from dirt or air.  This bee of ours cannot buzz alone.

Don't bother me today. I'm very busy collecting pollen from this flower.

Jon Sullivan, Public domain, via Wikimedia Commons

Just as you belong to a group of students, all living things belong to one group.  A lot of living things will be born together and stay in places where there is food they can eat.  You stay with students because you all learn together.  When talking about living things in general though, we say it's because they can make babies together.  A species is a group of living things that make babies with each other but not other living things.  It's like a club only for bees. 

Students hang out in schools.  Bees hang out in a hive.  They live together because they are stronger in numbers.  They all have the same needs when it comes to food and homes.  That means bees can help each other find pollen and students help each other learn new things.  A population is a group of the same kind of living thing all living together.  They stay strong by staying together.  It's a lot easier to squish one bee than it is a swarm of bees coming right at you.

If you find this in your back yard. Tell your mom or dad before you do anything else.

Bees need more than just other bees.  They can't eat other bees.  They can't build their hive out of bees.  They need many different kinds of living things around them.  They need flowers, and the flowers need the bees to help them make seeds.  After the bees make honey, there will be bears to come eat the hive so there are not too many bees.  A community is a lot of different kinds of populations living together: bees, flowers, bears.  At your school, that means students, teachers, the janitor.  No living thing can live without many other living things around it.

I've been looking all day for that beehive. Guess I'll take a rest here on this rock.

Bender Mike, U.S. Fish and Wildlife Service, Public domain, via Wikimedia Commons

By figuring out how a living thing works in the world we can understand so much more about how it affects everything around it.  You cannot learn about bees without learning how they act with other bees.  You cannot learn about bees without learning about flowers and maybe even bears.  You cannot learn about students without learning about teachers and principals.  Nothing grows alone. 

References:

Pidwirny, M. "Organization of Life: Species, Populations, Communities, and Ecosystems."  Fundamentals of Physical Geography, 2nd Edition, 2010.  <http://www.physicalgeography.net/fundamentals/9d.html>

Real Trees 4 Kids. "What's the System?" Real Trees, 2008.  <http://www.realtrees4kids.org/ninetwelve/system.htm>