"From an altitude of roughly 39,000 kilometers we had a splendid view of the planet we had come to explore. With an equatorial diameter of 6,563 km, Darwin IV is somewhat smaller than Earth. Its predominant color is dusky ochre, relieved by a sparse mottling of red and two crisply defined polar caps."

―Wayne Barlowe

The fourth planet in the Darwin Binary System, Darwin IV is the homeworld of an impressive diversity of native lifeforms. Once an Earth-like planet with large oceans, Darwin IV was too small to hold its water bodies for a long time: through the eras, it slowly lost its seas. Although Darwin IV is technically considered a desert planet for having little surface water and scarce precipitation, the planet is still thriving with life.

Contents 1 Location and physical aspects 1.1 Water 2 Ecology 3 Exploration 4 Sources 5 Behind the scenes

Location and physical aspectsEdit

Like its name suggests, Darwin IV is the fourth of six planets orbiting Darwin, an F-class binary star located in the Milky Way Galaxy, 6.5 light years from the Sol System. The two Darwin stars are located so close to each other that they often give the impression of being a single sun when seen from Darwin IV. This fact largely diminishes the odd daylight optical effects commonly found on planets orbiting a binary star. The length of Darwin IV's year is about twice that of Earth. Its day lasts for 26.7 Earth hours. The planet is orbited by at least two small moons.

In some aspects, Darwin IV is similar to the planet Mars. Both are similar in size, Darwin IV being slightly smaller, and both are believed to have had large oceans in the past, which eventually evaporated. In both worlds, most of the remaining water is now frozen in the ice caps, which recede and advance with the seasons. Unlike Mars, however, Darwin IV has a dense atmosphere, rich in oxygen and water vapor. The combination of a relatively weak gravity (0.6 of Earth) and an oxygen-rich atmosphere has allowed Darwin IV's native fauna to reach gigantic sizes, even in flying creatures.

Most of the surface of Darwin IV is covered by vast plains, especially on the areas which used to be the seafloor. Endless grasslands now dominate these areas, with scarce pocket forests of Plaque-bark Trees growing near the few lakes and rivers left. The planet is almost entirely encircled on the equatorial region by a large mountain range.

WaterEdit

"In a sense the succulent-rich savannas are the closest Darwin IV comes to true oceans, for the quantity of water trapped in the plants is vast."

―Wayne Barlowe

As stated above, Darwin IV currently has few liquid water bodies. Although there are lakes and streams, most of the planet's water is found in the atmosphere, frozen in the polar caps, or inside the bodies of living creatures.

On the northern hemisphere of the planet, there is a large region called the Amoebic Sea, which is actually a huge living entity, a colony of billions of microscopic organisms. This ten meters deep gelatinous being covers about five percent of the planet's surface and retains large quantities of water inside itself.

EcologyEdit

Darwin IV's plains are dominated by succulent plants, such as the Tube-grass and the Fodderball Weed. In the small pocket forests reside the largest floral organisms of the planet: the towering Plaque-bark Trees, which are home to creatures like the Daggerwrist and the Trunk-suckers, which feed on the trees' nourishing sap. Near the poles, the tundra region is blanketed by small gray-green lichen-like organisms.

Life in the skies of Darwin IV is as abundant as in the oceans of Earth. Countless tiny organisms, the aerophytes and microflyers, spend their whole lives floating in the skies of the planet and make up the main food source of most of Darwin IV's air-borne fauna. These minute creatures are so numerous that they sometimes darken the sky. Many of the large air creatures of Darwin IV are floaters, rather than flyers, having large hydrogen or methane-filled bladders to stay aloft. The largest of these floaters is the Ebony Blister-wing, which attains a wingspan of over 300 meters. Aerial predators like Skewers and Follow-wings propel themselves through the air by combusting methane. The small Jetdarters have a biological version of a ramjet engine – complete with a turbine of bone and gristle. The Eosapiens, large floating predators, are the only sapient species of the planet, yet their civilization is primitive and their technology is limited to spears and clubs.

The ground-dwelling creatures show a great diversity in morphology, though they all share some common characteristics. Darwin IV's terrestrial fauna is divided in four categories: monopedaliens (one leg), bipedaliens (two legs), tripedaliens (three legs) and quadrupedaliens (four legs). All predators on Darwin IV are liquivores: they secrete special enzymes to liquefy their meal before consuming it. One of the most notable traits of Darwin IV's fauna is the lack of eyes. Instead, the organisms rely on echo-location, similar to Earth's bats. Despite being blind to visible light, the organisms are able to detect light in the infrared spectrum due to thermoreceptors similar to those of Earth's snakes. Many creatures of Darwin IV are bioluminescent, and the light they produce is visible both in the infrared and the normal spectrum. Most organisms of Darwin IV are warm-blooded and full of energy. Both predators and herbivores are known for achieving great speed when running.

Besides plant-like photosynthesizers and animal-like consumers, there are also sessile predators on Darwin IV which fall in neither of the two groups, such as Electrophytes and Butchertrees.

ExplorationEdit

An expedition to planet Darwin IV was carried out by Humans and Yma in the year of 2358 and lasted about three Earth years. During this time the planet was explored and its unique lifeforms were studied. However, one of the objectives of the mission was to have the littlest impact possible on the planet's natural environment.

SourcesEdit

• Expedition: Being an Account in Words and Artwork of the 2358 A.D. Voyage to Darwin IV, by Wayne Barlowe

Behind the scenesEdit

The planet Darwin IV was named after the 19th century English naturalist Charles Darwin.