Tree of Life

Tree of Life is based on DNA sequence similarities.

For thousands of years and in many cultures, the Tree of Life has been an icon of creation, a symbol of life and a map of kinship.

Over the past 175 years, scientists have created various Trees of Life that seek to show how all creatures alive today have evolved from a common ancestor.

Today, a new Tree of Life is emerging that looks more like a network of branches than a traditional tree. This network appearance is due to mobile DNA  that transfers from one species to another, horizontally (indicated by converging branches.)

Phylogeny

These scientific Trees of Life, known as “phylogenetic trees,” show how all creatures are related  evolutionarily.

The image at right is a phylogenetic tree based on comparisons of DNA sequences. Pictures at top of the tree represent the diversity of creatures alive today. The base of the tree indicates the origin of LUCA, our Last Universal Common Ancestor. Numbers along the left side indicate the billions of years before the present. Although relatively simple and colorful, this Tree of Life image is based on data from hundreds of researchers using the tools of molecular biology.

Like most recent phylogenies, the phylogeny shown here is based in DNA sequence comparisons. Many of the newer trees feature Three Domains of life, an important classification scheme based on the genetic comparisons of conserved genes.  The tree shown here includes this information and adds recent data from genome sequencing that shows evolution due to horizontal gene transfer (mobile DNA transferred between different species indicated by convergent lines). In addition, this tree also provides a rough approximation of deep time.  This tree also has colorful images of representative organisms.

Other Trees of Life

This particular Tree of Life is inspired by phylogenies  and ideas of many authors, particularly the work of W. Ford Doolittle, who promotes the idea mobile DNA, and Carl Woese who discovered the Three Domains and who also talks about the importance of mobile DNA in evolution.  To see other phylogenetic trees created by other authors,  click here.

Lessons from the Tree of Life

The new, scientific tree of life offers us a wonderful perspective on how we evolved, how we all share an ancestor and similar genes. For more lessons from the Tree of Life, click here.

Poster Available at Zazzle.com

This image of the Tree of Life is available as a poster and greeting card at Zazzle.com.