Chapter 3 Principles of Cosmic Life and the Genesis of Life
The biological aspects are the vertical axis of the Model of Biodanza. At the bottom of the model, we first encounter the Principles of Cosmic Life and the Genesis of Life, which are indicated by the red box in Figure 3.1.
Figure 3.1: Model of Biodanza and Principles of Cosmic Life and the Genesis of Life
We will start with the genesis of the universe and we conclude with the genesis of life8. These two sections cover the concepts in the reader for Module IV Biological aspects of Biodanza on these topics.
3.1 Genesis of the Universe
An overview of the evolution of our universe is given in Figure 3.2.
Figure 3.2: Genesis and Evolution of our Universe (Source: NASA/WMAP Science Team, Wikipedia)
The most common theory is that our cosmos started with the Big Bang. A very energy-rich state.
As it expanded, the universe quickly cooled down enough for energy to be converted into mass, i.e. the majority in hydrogen and a fraction in heavier helium nuclei.
3.1.1 Genesis of Stars
Under the influence of the gravitational force, matter then started to cluster in nebulae, gaseous clouds essentially consisting of hydrogen (H) and helium (He).
Due to differences in concentration in these first nebulae, these clouds further contracted and eventually imploded (See Figure 3.3).
Figure 3.3: Genesis of the first stars (Source: universe-review.ca)
Extreme heating in the nebula that imploded by gravity gave rise to a condition in which all matter was in the form of a super hot plasma. In such a plasma nuclear fusion spontaneously takes place. In this process light atoms are combined into heavier atoms and much energy is released.
First, hydrogen in the core of the star is converted into helium (see Figure 3.4). The mass of the resulting Helium nuclei is slightly lower than that of the original hydrogen nuclei and the mass difference has been converted into energy.
Figure 3.4: Nuclear Fusion of hydrogen to the heavier helium (Source: Sarang, Wikipedia)
When all hydrogen in the core of a star is used up, nuclear fusion stops there, because a much higher temperature is needed to fuse helium (Figure 3.5).
Figure 3.5: Energy liberated by nuclear fusion. In a star nuclear fusion happens up to iron (Source: Wikipedia)
Without the energy from nuclear fusion, the core contracts under the influence of gravity, which makes it even hotter. As soon as the temperature is high enough, helium nuclei start to fuse into carbon and oxygen. For stars like our Sun, this is where it ends: they shed their outer layers as a colourful nebula, and a small, hot core remains, a white dwarf. In stars that are at least eight times more massive than the Sun, this process repeats itself again and again, forming ever heavier elements, up to iron (Figure 3.5). The fusion of iron, however, no longer releases energy. Once the core consists of iron, it can no longer withstand gravity and collapses in a fraction of a second. This collapse causes a gigantic explosion: a supernova (see Figure 3.6). The newly formed elements are hurled into the universe, and elements even heavier than iron are formed as well. Such heavy elements are also formed when two neutron stars, the ultra-compact remnants of collapsed stars, collide.
Figure 3.6: Supernova of a star (Source: www.universetoday.com)
From the material that stars eject in this way, new nebulae are formed, which eventually lead to new stars, and the whole process begins all over again.
Hence, through nuclear fusion in the stars the heavier atoms have been generated of which the bio-molecules of life are eventually built. So we are built out of stardust!
3.1.2 Hydrocarbons in Interstellar Space
Upon nuclear fusion in the stars many different elements are formed. For biological life, hydrogen, carbon, oxygen, sulfur, phosphorus and nitrogen atoms, among others, are key to compose organic matter.
In interstellar space, carbon reacts spontaneously with other elements to form polycyclic aromatic hydrocarbons (PAHs), ring-shaped molecules of carbon and hydrogen, similar to the molecules in soot. This is for instance visible in a photograph of the Cat’s paw nebula (Figure 3.7). In the green regions radiation of hot stars induces fluorescence of PAHs.
Figure 3.7: Cat’s Paw nebula, in the green regions radiation of hot stars induces fluorescence of PAHs (Source: NASA/JPL-Caltech, Wikipedia)
PAHs could form as soon as the first stars had produced carbon and spread it into space. Laboratory experiments suggest that, under the influence of UV radiation and through reactions with hydrogen, oxygen and nitrogen among others, they can be further transformed in interstellar space into precursors of amino acids and nucleotides, the building blocks of proteins and of RNA and DNA, respectively.
That the building blocks of life emerge in space is supported by what we find in our own solar system. The amino acid glycine was detected around comet 67P/Churyumov-Gerasimenko (Altwegg et al. 2016). And in samples that the OSIRIS-REx spacecraft brought back to Earth from the asteroid Bennu, researchers found 14 of the 20 amino acids used by life on Earth, as well as all five nucleobases of DNA and RNA (Glavin et al. 2025). Because these samples never came into contact with Earth, contamination by terrestrial life can be ruled out. Hence, the building blocks of life also arise spontaneously in space!
These recent findings confirm what Christian de Duve already wrote in 2002: “Life is an obligatory manifestation of matter, written into the fabric of the universe” (De Duve 2002).
3.2 Genesis of Life
In a remote corner of our Milky Way, which is an average galaxy, an average planet was formed, which we know as our planet Earth. After the Earth cooled down liquid water was formed. The unique features of liquid water are essential for life as we know it. Indeed, once liquid water was available, biological life emerged in less than 300 million years, which is a very short time interval on the geological timescale.
So on earth conditions emerged that made the “genesis of life” as we know it, possible. The exact process that led to the life forms on earth is unknown and will probably remain so. However, a general rationale is displayed in Figure 3.8.
Figure 3.8: Stages in the origin of life range from well-understood, such as the abiotic synthesis of simple organic molecules, to largely unknown, like the origin of the last universal common ancestor (LUCA) with its complex molecular functionalities. (Source: Chiswick Chap, Wikipedia)
First, a chemical evolutionary process gave rise to organic molecules with increasing complexity. According to the most widely held hypothesis, the RNA-world hypothesis, RNA molecules played a key role in this. Indeed, RNA molecules can both carry genetic information and catalyse chemical reactions. Under oxygen-free conditions and in the presence of iron, as on the young Earth, RNA can moreover acquire additional catalytic functions (Hsiao et al. 2013). It has also been shown in the lab that an RNA molecule can build another functional RNA molecule from individual building blocks (Wochner et al. 2011), although an RNA molecule that can fully copy itself has not yet been found. Whether the first RNA molecules evolved alone, or early on together with proteins or a simple metabolism, is still an open question.
Next, it is assumed that prebiotic molecules, which could self-replicate, were encapsulated by phospholipids, which spontaneously form membrane like structures. This resulted in a protocell with a membrane (see Figure 3.8). In these protocells a further chemical evolution was possible, separated from the environment, which ultimately led to a self-replicating and self-organizing cell that was built from the four essential types of bio-molecules of life: lipids, carbohydrates, proteins and nucleic acids.
Further biological evolution of these first living cells eventually gave rise to our last universal common ancestor (LUCA). By comparing the genes of present-day bacteria and archaea, scientists can reconstruct which genes LUCA must already have had. A first study found 355 protein families that trace back to LUCA (Weiss et al. 2016). A more recent analysis estimates that LUCA lived about 4.2 billion years ago and had a genome encoding some 2,600 proteins, comparable to that of present-day bacteria (Moody et al. 2024). So LUCA was already a complex cell. It stored its hereditary material in DNA, used the same genetic code as we do, and produced proteins in ribosomes from RNA templates. LUCA lived without oxygen (anaerobic) and probably obtained its energy from hydrogen and CO\(_2\) in a geochemically active environment, such as hydrothermal vents on the ocean floor (Weiss et al. 2016). Moreover, LUCA probably did not live in isolation, but was part of an ecosystem with other microorganisms (Moody et al. 2024). And eventually LUCA evolved into all species that currently live on Earth.
Now that we have introduced the genesis of life, we can focus on the tale of the evolution of LUCA into all species of the tree of life, a process which is also referred to as phylogenesis.
References
Here life has the meaning of biological life and not the broader view that Rolando has on life↩︎