Life, As We Know It

Introduction: Welcome to life! In this section, you will have the opportunity to see how life is organized, shared characteristics and the differences between human and ape. An interesting fact found in our textbook is that humans cannot have evolved from apes because we are living on the earth at the same time. Yet we do share a common apelike ancestor.

Definitions (All from “Human Biology” by Mader, Sylvia S.)

Metabolism: All of the chemical reactions that occur in a cell.

Development: Groups of stages where a zygote becomes an organism or an organism changes during its lifespan.

Homeostasis: Maintaining internal conditions.

Evolution: Descent of organisms from common ancestors with adaptations.

What All Living Things Share

Here is a great way page that goes through the seven characteristics of life. It really cannot get simpler than this. http://infohost.nmt.edu/~klathrop/7characterisitcs_of_life.htm

For a quick reference, here is a list:

Living Things:

-Are composed of cells

-Are organized

-Use energy

-Respond to their environment

-Grow and develop

-Reproduce

-Evolve/adapt

Organization

This is best explained by graphics.

Here is a very simple chart from http://infohost.nmt.edu/~klathrop/7characterisitcs_of_life.htm that leaves out the first level of atoms and doesn’t expand much into community, ecosystem, and biosphere.

I find the best way to think of this organization is this: All things are composed of atoms. A bunch of atoms make a molecule. A bunch of molecules make a cell. A bunch of cells make a tissue, so on and so forth until you have a bunch of ecosystems to make a biosphere.

Differences

Some of us (or most of us) may look like apes, but we have a lot of differences. According to our textbook, here are a few differences.

HUMANS	APES
Highly developed brains	Not so highly developed
Stand completely upright	Use front arms and back legs to walk
Creative language	Grunt and make other noises
Ability to use lots of tools	Use sticks and rocks

Conclusion: You have just gone through a very brief introduction to life and our organization. Next we are going to delve a little deeper in the molecules of life. From there we will go into depth about cells.