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Sagan 4

Sagan 4 is an alien planet ecosystem project originally started by Hydromancerx inspired by Carl Sagan's video. Life on this alien planet started from a single-celled organism. It is now populated with many species of flora and fauna all created by artists who love drawing and xenobiology. Submissions take place on the Sagan 4 Beta subforum of the official Sagan 4 forum. We also have a Discord server which is open to members and spectators alike.

Awards	Badges	Biochemistry	Biomes
Climate	Dioramas	Disasters	Disorders
Ecosystems	Food Webs	General	Generations
Geologic Timescale	Landmarks	Size	Solar System
Species	Taxonomy	Template Wizards	Weeks

Introduction

Sagan 4 is a planet with conditions similar to Earth. All of its life derives from a single cell, Protosagania. Its major kingdoms are Binucleida, an incredibly diverse group in which each cell has two or more nuclei, ranging from microbes to the tallest trees, Carpozoa, which tend to be fairly animal-like but include some single-celled and colonial species, and Photosagnia, purple photosynthesizers that include clouds of microbes in the oceans and some of the first flora on land.

Binucleida's two largest lineages originated from a symbiosis. One organism produced a chitinous outer shell, and another provided a soft inner core. One of these lines is the crystal flora, in which the outer shell is usually photosynthetic and crystal-shaped; these dominate many of Sagan 4's photosynthetic niches.

The other line of symbiotic Binucleida is the binucleid worms, in which the outer shell forms a segmented exoskeleton. The biggest group of binucleid worms is the knightworms (descendants of the common knightworm), which often resemble Earth's arthropods. They range from tiny crawlers to large creatures with legs, and they include two of the first fauna on land. They are mostly found around and on the western continent, Glicker. The next-biggest binucleid worm group is Heliovermis (descendants of wormstem), which are able to photosynthesize. They tend to have an animal-like juvenile phase and a plant-like adult phase. Heliovermes are mostly found on and around the eastern continent, Wright.

Carpozoa's biggest lineages are Luceremundaria, which often have colorful bioluminescence and range from fish-like to cup-shaped, and Asterzoa, a diverse group whose original body plan was shaped like a four-armed star.

The biggest Luceremundarian group is Geletaventria, superficially similar to fish, but with a four-tentacled mouth. Some Geletaventrians are soft-bodied, while others have armor. Luceremundaria also includes Carpolantaia, which are generally cup-shaped and gelatinous, mostly floating, though some are sessile or crawl.

Asterzoa is split into Asterzalia, many of which have become bilateral swimmers and crawlers, including species with skeletons and formidable jaws, Asterstreidia, radial species, mostly filter-feeders and mostly sessile, many of them shelled, and Asterfolia, which have developed photosynthesis through symbiosis, some of which have become more plant-like and some with more active lifestyles.

There are several additional smaller kingdoms. One is Mancerxia, which currently mostly consists of virus-like microbes. Another, Goliathpseudopodia, consists of large single-celled organisms, some of which are over a centimeter in size. Lituswushia, Skarlixia, and Ferrumcarceria all metabolize various metals in different ways. The Taxonomy page contains a full list of Sagan 4's kingdoms.

Fun facts:

Life is recovering from a mass extinction involving a crash in oxygen levels and in bioavailable nitrogen.

The largest floral organism ever was the Greatest Crystal Fortress at 480 meters wide and 240 meters tall!

The large floral organism currently is a tie between the Crooked Cushio and Tallahassee Fringeweed at two meters tall.

The largest marine fauna ever was the Filter Chad at 12 m long.

The largest marine fauna currently is the Ophaniroth at three meters long.

The largest land fauna ever was the Gigantaurok, at 5.6 m tall.

The largest partially terrestrial fauna currently is the Lunger at two meters long.

The largest fully terrestrial fauna currently is a three-way tie between the Pallazor, Inkblot Notback, and Northern Notback, at one meter long.

Life has spread across much of the planet, but deserts and montane areas are still relatively barren, as are cave and the deep underground water tables.

Below is a random selection of extant species; click any one of them to learn more!