What is life?

Unless a cell can 1) grow and 2) divide, it doesn't have the essence for life to evolve.

This is how seeds blossom into flowers, how caterpillers become butterflies, and how babies become adults. 

To be truly alive - cells need genes.  Genes are the molecular identity that can pass from a cell to its copy.  All modern life does this with the double helix of DNA.  It is the most complex chemical molecule we know made up of 10s of  billions of atoms.  DNA controls every detail of every living thing.  The colour of our eyes, the shape of the leaves on a tree, the way even the most simple bacterium swims.  And every time a cell divides, it places a copy of its DNA in both cells of the new generation. 

Early life needed 2 things:  

1  The cell membrane - a container to live in and keep other things out.

2  Some genetic material.  Something that can allow the inheritance of information. 

Every modern creature uses DNA to do that.  It's an organisms instruction manual.  Genetic code spelled out in chemicals inside the twisty double Helix.  DNA has long been hailed as the fundamental molecule of life.  We also have RNA, usually described as DNA's helper, but it turns out that RNA has a genetic code written with chemicals - ACGU.  They're used to help build the proteins that make up the cells in our bodies - skin, hair, brain cells, the heart.  RNA helps make them all. 

RNA is made of 3 parts, a sugar, a phosphate and a single letter of the genetic code (a base). 



When did we start wearing clothes?

It is estimated that 170,000 years ago is when modern clothing lice split from head lice and 'dates' when we started to wear clothes.  The clothes allowed our ancestors to migrate to colder climates (leave Africa). 

We started living in 'dwellings' 500,000 ago

We began using fire 800,000 years ago

Toolmaking began 3.3 million years ago

Pubic lice (Crab lice) developed around 3,000,000 years ago estimating that that is when we lost our body hair.  When we were still small chimp-like creatures with few of the qualities we consider human.