What's New :
UPSC CSE Result 2023.Download toppers list

New evolutionary law explains how living beings, minerals & species evolve

  • Published
    18th Oct, 2023
Context:

Recently, the Scientists have proposed a new evolutionary law that can explain the evolution of living and non-living entities, from minerals to stars.

Highlights of the study:

  • The study aims to establish a relationship between evolution of living beings, minerals and stars.
  • As life evolved from single-celled to multi-celled organisms, Earth’s minerals, also became more complex, creating diversity. This, in turn, drove biological evolution.
  • The researchers proposed that evolution occurs when a new configuration or a new arrangement of atoms and molecules works well and functions improve.
  • In contrast to Darwin’s theory of evolution, it defined function as primarily with survival but the new study highlights at least three kinds of functions that occur in nature.
    • The first function is stability, which means systems made up of stable arrangements of atoms or molecules will continue to survive.
    • The second one includes dynamic systems with energy supply.
    • The third is “novelty” — the tendency of evolving systems to explore new configurations or arrangements that can give rise to new behaviours or characteristics.

An example of novelty is when single-celled organisms evolved to use light to make food.

Other examples include new behaviours among multi-cellular species such as swimming, walking, flying and thinking.

  • Similarly, early minerals on Earth possessed a stable arrangement of atoms, which acted as foundations for the evolution of the next generations of minerals.
  • These minerals were then incorporated into life. For example, minerals are present in living organisms’ shells, teeth and bones.
  • As for stars, the first ones that formed after the Big Bang had two main ingredients: Hydrogen and helium.
    • Those earliest stars used these ingredients to make about 20 heavier chemical elements.
    • The next generation of stars consequently produced almost 100 more elements.
  • The universe generates novel combinations of atoms, molecules, cells, etc.
  • Those combinations that are stable and can go on to engender even more novelty will continue to evolve.

What does the Evolution mean?

  • Evolution is a process of gradual development in a particular situation or thing over some time and also a gradual change in the characteristics of a population of animals or plants over successive generations.

What are the evidences of evolution present?

  • The evidences supporting organic evolution are derived from a number of fields of Biology. Those discussed here are:
    • Morphological evidences
    • Embryological evidences
    • Palaeontological evidences
    • Molecular evidences

Mechanism of Evolution

  • Various theories about the mechanism of evolution have been proposed; some of them such as Lamarck’s theory of “Inheritance of acquired characters” and De Vries’ theory of ‘mutation’ are now of historical importance only.
  • Darwin’s theory of Natural selection: It still holds ground but was modified with progress in genetics and developed into the Modern synthetic theory which is regarded as the most valid theory of evolution.
    • According to Darwin “when the environment changes, new adaptations get selected in nature and after many generations sufficient characteristics will have been changed so as to alter the species into a new one (origin of species).”
  • Modern Synthetic Theory:
    • The unit of evolution is ‘population’ which has its own gene pool. Gene pool is the group of all different genes of a population.
    • Heritable genetic changes appear in the individuals of a population. These heritable changes or variations occur due to small mutations in the genes or in the chromosomes and their recombination.
    • Natural selection selects the variations which help in adapting to the environment.
    • A change in the genetic constitution of a population selected by natural selection is responsible for evolution of a new species, since through interaction of variation and Natural Selection more offsprings with favourable genetic changes are born. This is called ‘differential reproduction’.
    • Once evolved, Reproductive Isolation helps in keeping species distinct.

Sources of organic variation:

  • Variation arises in an individual member of a population, and if favourable, spreads into the population through “differential reproduction” by the action of natural selection.
  • Variations may occur by;
  • Mutation, which is a sudden genetic change. It may be a change in a single gene (genic mutation or point mutation) or may affect many genes (chromosomal mutation).
  • Genetic recombination, which occurs in sexually reproducing organisms at every reproduction. The chromosomes and thus genes of the parents mix at random during zygote formation. That is why offspring of same parents are different from each other as they have different combinations of parental genes. Variation is also brought about when crossing over occurs during gamete formation.
  • Gene flow is when there is chance mixing of genes of closely related species through sexual reproduction.
  • Genetic drift occurs in small populations when a part breaks off from a large population. Only representative genes of the large population are present which undergo change at a right time and the small population may evolve into a new subspecies or species.
GS Mains Classes GS Classes 2024 UPSC Study Material
X

Verifying, please be patient.

Enquire Now