From 100,000 year-old sea grass to 5,000 year-old Antarctic moss - these are the world's oldest living organisms

Extreme age is really quite hard to comprehend. Up to a point, it's easy to say that a bigger tree is older than a smaller one, but once you get into the realms of the truly ancient, size no longer equates to age.

Some of the world's oldest living organisms don't seem any different from plants you might stumble upon on a daily basis, especially if you live somewhere warm. But there are trees older than Christianity, mosses that pre-date the pyramids, and colonies of sea-grass that began life when Homo sapiens was still evolving.

One artist - photographer Rachel Sussman - took it upon herself to visit some of the world's most inaccessible and inhospitable locations to seek out the longest-living species on the planet.

The results have been published in her new book, The Oldest Living Things in the World, and make for thought-provoking viewing.

Each one of these species presents something unique, some set of extraordinary attributes that have helped it adapt for extremely long life.

For example, the South American shrub La Llareta is a distant relative of parsley, and grows so densely that you could stand on it, giving it the appearance of moss covering rocks. It is 2,000 years old, and flourishes in the Atacama desert, arguably the world's toughest environment.

Another remarkable plant is Welwitschia mirabilis, a primitive conifer that exists only in parts of coastal Namibia and Angola, in south-west Africa, in regions where the moisture from the sea meets the heat of the desert.

It only has two leaves (despite appearances), which it never sheds. It too is 2,000 years old.

Elsewhere, Sussman visited Antarctic moss on Elephant Island which has survived for 5,500 years. It grows near where Shackleton's expedition was marooned 100 years ago, a deeply unfriendly location to native species.

These Huon Pine trees in Tasmania have been recently destroyed by fire, but others survived. The living population is dated as being 10,500 years old - all the trees are part of the same genetically identical colony.

Last but not least, Sussman's work took her to the Mediterranean, near Ibiza, where a colony of sea grass exists that first took seed a staggering 100,000 years ago. The grasses all belong to a genetically identical colony that survives by cloning itself over and over again - a process that has continued without sexual reproduction since Homo sapiens first evolved.

This map details some of the other locations and species which were covered in the book. Sussman, who was recently awarded a Guggenheim fellowship, published a total of 125 images of 30 subjects in her book, which was released yesterday.