Theory Of Organic Evolution

Biological evolution with change or modification is the fundamental concept of evolution. The literary meaning of evolution is to reflect changes from time to time either openly or unsuccessfully. Organic evolution means that today’s entities are the result of a long and continuous chain of events that cause changes referred to as organic evolution. The vast biodiversity present on Earth to date is responsible for this evolutionary phenomenon occurring over thousands of years.

Evolution Theories

Evolution corresponds to changes in the form and behaviour of organisms generation by generation. It refers to the change within the lineage of a population from generation to generation.
Several theories have been put forward to substantiate and explained the evolutionary process. Some of these sources are listed below:

Darwin’s Theory of Evolution

Lamarckian Theory Of Evolution

1. Darwin’s Theory of Evolution

Targeted organic evolution proposed by Charles Darwin emphasizes “civilized with modification” and begins that the current complexities in animals and plants result from the evolution of simpler forms that previously existed through final transformations.

Darwin’s “Origin of Species” book in 1859 was the first to advance the theory of evolution through natural selection, stating that changes in inherited behaviour and physical characteristics result in institutions, a period of change. pass through. time. These changes allow the species to adapt to the changing environments, which helps in the survival of the offspring.

The evolution of natural selection is one of the best theories supported by evidence from the area of scientific disciplines such as genetics, geology, palaeontology, developmental biology, etc.

The theory highlights the important points are, according to the scientist of Brian Richmond, which is – “all life on earth is connected and related to one another” and that the diversity of life is the result of modifications of populations through natural selection in which certain characteristics are transferred to the environment. was selected in. over others. Sometimes, the principle “survival of the fittest” can be confused with your goal. 

Research and Observation of Darwin’s Theory-

Origin of Whales

In the first edition of “On the Origin of Species”, Charles Darwin speculated about the role of natural selection in turning a mammal on land into a whale. Charles Darwin used to prove our statement which is used as part of a hypothetical example, A North American black bear known to swim and hunt with its mouth open.

Natural Selection

To understand the origin of whales, it is important to have a fundamental understanding of the mechanisms of natural selection. The phenomenon of natural selection can change a species in a small way that causes a change in the colour/shape of a population from generation to generation. This is called microevolution.

Furthermore, the process of natural selection can accumulate changes and create an entirely new species known as macroevolution. This amphibian could turn mammals into whales, dinosaurs into birds, and apes the ancestors of humans.

Darwin explained a natural selection form based on the success of an entity in attracting a mate, a process called sexual selection. The horns of male antelope and peacock feathers are good examples of the characteristics developed in this type of selection.

Modern Interpretation

The inclusion of genetics and Darwin’s theory is known as the modern evolutionary synthesis, which came after Pobiner said that Darwin only noted patterns of evolution and could not put forward the mechanism. This came after the discovery of how genes encode various behavioural or biological characteristics and their inheritance.

At the level of genes and DNA, behavioural and physiological changes fall that make natural selection possible. These changes are known as mutations which are the raw information on which evolution acts, the added Pobiner Mutations can be from random errors in replication of DNA repair, radiation, or chemical damage. These are mostly neutral or harmful and rarely beneficial. It becomes prevalent in the subsequent generation spreading in the population.

2. Lamarckian Theory Of Evolution

The first theory of evolution was Lamarckism given by Jean-Baptiste de Lamarck, the framework of this theory appeared only in 1801. He is responsible for coining the terms “Annelida” and “Invertebrate”.

Lamarck’s Proposals

The four main works proposed by Lamarck are given below:

• Inner Vitality – This force causes all living things and their constituent parts to continually increase
• Effect of Environment and New Needs – Environmental changes have an effect on living entities by which they give rise to new needs. These needs generate new structures that change the habits of institutions.
• Use and disuse of institutions – more use of organs leads to better development, but the use of organs leads to degeneration
• Inheritance of Acquired Traits – All these above factors result in adapted traits which are passed on to the next generations. It is a continuous process. These variations accumulate over generations to form a new species.

Examples in support of Lamarckism:

• webbed toes of aquatic birds
• evolution of giraffe
• missing limbs in snakes
• flightless bird
• flatfish
• cave dweller

Mechanism Of Organic Evolution

The phenomenon of genetic variation is fundamental to biological evolution. It is on this that selective forces act for development. The mechanism of development emphasizes:

• Lineage and genetic differences can be inherited by the next generation. Natural selection as a mechanism of genetic drift, migration, and mutation, changes
• the importance of genetic variation
• Consequences of the reduction of genetic variation and the random nature of genetic drift
• Effect of different species on each other’s evolutionary process through co-evolution
• Role of differential reproduction, variation, and heredity in evolution by natural selection

Evolution is observed in a population because it contains genes in the gene pool, changes in this pool lead to evolution. There are 5 characteristics of Evolution:

1. Mutation

It is the driving force of development. It can be a random change in the genetic structure that has an effect on the gene pool of the population. This change in the nature of DNA in 1 or more chromosomes produces new alleles, therefore causing genetic variation. Natural selection is decisive in eliminating the less fit in mutations, allowing survival of the fittest.

2. Natural selection

This occurs when institutions are left in an environment where survival of the fittest is observed. When these characteristics are inherited in the offspring, they make the population reproduce better to adapt to the changing environment. The traits of less-fit entities are less likely to be passed on to future generations. In natural selection, the important selective force is the role of the environment.

For example, the ability to attract and mate can also be viewed as a measure of fitness. Those that are better adapted produce comparatively more offspring, passing on their genes at a higher success rate than those that are less adapted.

3. Gene flow

The migration of entities may cause a group of them to move to a new geographic location. When migratory entities interact with newly introduced populations, they result in local populations adding new genes to the already existing gene pool, thereby contributing to gene flow.
For example, gene flow occurs when pollen grains are blown by the wind out of reach of the parent plant population. Some animals may be transferred away from the herd by forcing them to move to a new location, interbreeding, and introducing new genes into the pool.

4. Genetic drift

This can happen when a small population moves to a new geographic location, setting up an entirely isolated area. For example, when some fish are introduced into a lake, over time the population is separated from the parent. This process does not happen in densely populated areas.

5. Development of Species

Species are a specialized group of entities sharing many traits with the ability to interbreed with each other, to produce fertile offspring. These usually share the same gene pool.

Species evolution occurs when a specific population becomes isolated as a result of geographical barriers. This phenomenon may also be accompanied by the development of reproductive barriers.

For example, when a population develops structural constraints that make it difficult to mate with members of the same population, a new species is formed. Species may also have evolved as a result of spatial differences and the timing of sexual activity.