The first animal on Earth

A study of the evolutionary history of animals has shown the first animal structure on Earth - a mystical creature that we can only speculate on its characteristics based on fossils as well as research. saving from surviving species - perhaps even more complicated than we previously believed.

This research was funded by the National Science Foundation and published in the front page of the Nature issue April 10, 2008. Thanks to high technology in the analysis of large amounts of genetic genes, the study identified the earliest branching point at the base of the animal genealogy. Charles Darwin was the one who introduced the tree of life with a stratified structure according to the evolutionary relationship between species.

Change the tree of life

One of the study's surprising findings is that the comb jellyfish has separated from other animals and traveled on its own evolutionary path before the sponge. This interesting surprise surprised the traditional views that the tiny sponge is the earliest branching evolutionary animal at the root of the tree of life. Dunn said: 'This is such a shock, that we initially thought there was a mistake somewhere'.

The evolutionary history of the jellyfish reveals the first surprises on Earth (Photo: Casey Dunn)

But even if Dunn's team checked the results and added more data, what they got was just a jellyfish whose tissue and nervous system were separated from the another species before the sponge (no tissue, no nervous system)

Also according to Dunn, the appearance of comb jellyfish representatives with a relatively complex structure at the root of the tree of life proves one thing that the first animal on Earth is probably much more complicated. we still think.

While still cautious that more research is needed to corroborate the team's findings, Dunn said the comb jellyfish could only overcome the simple sponge of 'life' thanks to a in the two evolution scenarios below:

1) Jellyfish evolve complexly independently of other animals, after it splits to make its own evolutionary path.

2) Sponges have evolved into a simple form from more complex organisms - according to Dunn, this is an ability to emphasize the fact that 'evolution is not necessarily higher in order to increase the level. complex. This evolutionary scenario will be an authentic and typical example of the above rule. '

From when?

When did the first comb jellyfish branch off? 'Unfortunately, we don't have fossils of the oldest jellyfish', Dunn said sadly. 'Therefore, there is no way to determine the time of the first jellyfish's appearance and the time when it splits its branches on the tree of life'.

According to Herendeen, after being separated from other species, perhaps the comb jellyfish still evolved. Therefore, the comb jellyfish on this day look very different from the original jellyfish.

Also according to Patrick Herendeen, director of the National Science Foundation, soft-edged but non-dome-shaped soft-comb jellyfish have undergone a different evolutionary path than the domed jellyfish. This separation shows that 'jellyfish classified by body shape have evolved independently from each other several times'.

The space left on the tree of life

In addition to reversing the evolutionary order of combs and jellyfish, Dunn's research also answers long-standing questions about other species. Among them is the question of whether polyhedra has a closer relationship with spiders or insects. The answer is spider.

Despite the above answers, along with the important evolutionary findings of the group, the tree of life is still in the process of being established. Dunn said: 'Scientists now estimate that there are about 10 million species of organisms all on Earth. But until now, only about 1.8 million species - most of them animals - were studied by scientists. Very few species are filled with names on the tree of life '.

(Photos: Flickr Collection)

Breakthrough method

At least some of the remaining space on the evolutionary tree will be able to be filled using high-tech analysis methods that were first applied in Dunn's research. The above method requires the use of 100 computers to analyze a larger volume of data than any of the previous evolutionary studies combined. Herendeen said: 'Dunn's high-tech method is what we need to continue to establish the tree of life. This method will be applied more in the future. '

Dunn explains one of the benefits of the method that his team applies: 'Although we only observe less than 100 species, they are sampled in a way that shows the relationship of dynamic groups. The main object corresponds to each other. Therefore, this study as well as similar studies implies sites on the evolutionary tree of many species rather than modeled species'.

The challenge is still there

But no matter how modern the tools scientists use to analyze the genes of living organisms, they still have to conquer the challenges faced by naturalists from 200 years. before'. 'We don't even know exactly how many species there are to know where to find them,' Dunn said.

'Even when DNA analysis of organisms becomes easier and more economical with modern computers, it is still very expensive and difficult to find, collect and identify organisms.' For example, Dunn's team had to use underwater remote control devices to collect a comb jellyfish for research.

Dunn concludes: 'Surprisingly, despite the great advances in technology, we face daily challenges like naturalists 200 years ago: to find out how many species live. on our planet, where to find them and how to collect them '.