Evolution

1. THE MISSION

Imagine in the game, you have the special skill of listening to the past through various fossils and archaeological ruins and what they want to convey. They tell you the history of the species, the process of evolution. You then as a person with special skills start to use Natural and Artificial selection and create a lot of species that can survive and thrive. Bringing together your understanding of evolutionary relationships and human evolution, the gamer plans to develop an universe where through Natural and Artificial Selection all forms of organisms and species are formed for growth and development and the player gains 500 points during the steps of this extensive process.

2. CONCEPTS

 Natural Selection

• It is the phenomenon by which a favourable trait in a population of a species is selected.
• Changing natural conditions exert equal pressure on all the existing species.
• The species/organisms which are better adapted to the changing conditions survive and reproduce i.e. selected by nature and species/organisms which cannot adapt perish i.e. rejected by nature..

1. Speciation

Genetic drift

Natural selection can play an important role in deciding the traits that survive in a population. However, random fluctuations in gene variants are seen on many occasions. This phenomenon is known as genetic drift. Thus, genetic drift is a change in the frequency of an existing allele in a small population.

Genetic drift may cause a gene variant to disappear from the population and thus reduce genetic variation.

Speciation

It is the process of formation of a new species from existing ones due to several evolutionary forces like genetic drift, isolation of populations, natural selection, etc.  Speciation leads to diversity in the ecosystem and the diversity and diversity lead to evolution.

Gene flow

Gene flow is the transfer of genes from one population to the next.

Population

A population is a community or a group of animals, plants or any living organism that can reproduce with each other and have fertile, viable offspring.

Charles Darwin

Charles Darwin also called “Father of Evolution” was an English Naturalist and Biologist. Five years expedition in a ship called HMS Beagle to Galapagos Island helped him write his theory of evolution. In 1859 he published a book called Origin of Species, in which he put his theory of evolution in detail.

1. Evolution & Fossils

Evolution

Evolution is a tangible change in the heritable characteristics of a population over several generations. These changes can give rise to a new species or the species might change themselves to become better adapted to the surrounding environment.

Origin of species

After a successful expedition on HMS Beagle, Charles Darwin wrote a book on what he observed at the Galapagos Islands. In the book named ‘The Origin of Species’, he wrote a detailed theory of evolution which was mostly based on Natural Selection.

Origin of life – Haldane’s theory

JBS Haldane was a British Scientist who theorized that life originated from organic and lifeless matter. His theory was proved to be correct by Urey and Miller’s experiment. It was called the theory of abiogenesis.

Evolutionary evidence – fossils

There are plenty of pieces of evidence to support the theory of evolution. Fossils happen to be the biggest of them. Fossils are the preserved remains of ancient animals or plants that died millions of years ago.

The fossils help us understand the anatomy and even physiology of these organisms and understand how evolution worked and led to the formation of organisms that we see today.

Formation of Fossils

Fossils are important pieces of evolutionary evidence and are formed by the following steps:

• Organisms die and they get buried in mud and silt.
• The soft tissues of the body get quickly leaving behind the hard bones or shells
• Over time sediments build over it and harden into rock
• As the bones decay, mineral seep in to replace the contents cell by cell, process called as petrification
• If bones decay completely, it leaves behind the cast of the animal.

Evolutionary relationships

Evolutionary relationships of animals can be deduced by studying the homologous organs and analogous organs.

Homologous organs are those which have a similar structure but different function.

• Wings of birds and forelimbs of mammals: they have similar structure but are modified to suit different functions
• A tendril of pea plant and spine of barberry plant: both are modified leaves, but perform different functions.

Analogous organs are those which have a similar function but a different structure and origin too.

• Wings of bats, birds and wings of insects: both are used for flying, but structurally are very different
• Leaves of opuntia and peepal: both perform photosynthesis, but leaves of Opuntia are modified stem whereas peepal leaves are normal leaves.

Evolution by stage

Evolution is a slow process and does not happen overnight. There are several stages in the evolution of almost every animal that we see today. Complexities do not evolve suddenly, but evolve bit by bit and may have limited use at certain stages. This gradual evolutionary process is called evolution by stages.

Artificial selection

Sometimes a single species can evolve into several different species due to artificial selection. E.g. the cabbage family. A single ancestor in the cabbage family gave rise to several different species due to the selection of different traits.

Molecular phylogeny

The evolutionary relationship among different biological species is called phylogeny. It gives rise to an evolutionary tree. In molecular phylogeny these relationships are studied at the hereditary molecular level, mainly using DNA sequences. It involves the analysis of DNA composition and gene comparison between different species.

1. Human Evolution

Humans are known to belong to the primate family. Humans today have a very close genetic connection to chimps and other primates. While the complete evolutionary process of Humans from Primates is still a mystery, a larger picture of human evolution has been formed. Some of the ancestors of Humans include Dryopithecus, Ramapithecus, Australopithecus, Homo erectus, Homo sapiens neanderthalensis, Cro-magnon man, and finally us, the Homo sapiens. Human evolution traces back to Africa. Then they migrated all over the world