Evolution

Introduction

The frequency of an inherited trait can change over generations, and it leads to Evolution. Variation gives a survival advantage. It is naturally selected. Genetic drift happens when diversity occurs without any adaptations.

Acquired Traits and Inherited Traits

• Inherited traits are those which are obtained from the parents via the transfer of genetic material
• Acquired traits are not inherited, rather develop during the lifetime of an organism

Speciation

Speciation can be defined as an evolutionary process by which species or populations evolve to become distinct species.

• Variations in the species merely contribute to the genetic drift or provide survival advantages
• The processes of genetic drift and natural selection result in isolated subpopulations becoming more and more different from each other
• If the DNA changes are severe enough, as a change in the number of chromosomes, the germ cells of the two groups cannot fuse, and, hence, new species are generated
• Speciation takes place when variation and geographical isolation combine

Evolution and Characteristics

• The term characteristics can be defined as details of appearance or behavior i.e., a form or a particular function. For instance,
  ⮚ Humans having four limbs is a characteristic

•  ⮚ Plants can perform photosynthesis is also a characteristic
• The characteristics in the next level of classification are shared by most, but not all organisms
• One of the basic characteristics of cell design that makes a difference among different organisms is whether the cell has a nucleus or not
• Two species are closely related if they have more and more characteristics in common

Tracing Evolutionary Relationships

• Homologous characteristics can help you identify the evolutionary relationships between seemingly disparate genus. For example, Limbs in humans, frogs, cows, dogs, etc.
• On the contrary, all likenesses simply in organ shape are not only because of usual ancestry but are derived from analogous traits. For example, Bird Wings, Bats, Eagles, vultures, etc.
• One can trace evolutionary relationships in the classification of organisms
• Tracing common ancestors gives us the idea that at some point in the past, non-living things or materials must have given rise to life
• Evolution and characteristics can be found out not just by studying living species but also non-living materials such as fossils

Fossils

Bodies of organisms decompose and become lost after their death. Occasionally, some environmental factor does not let it decompose completely. All such traces of living organisms that are not decomposed are called fossils. The following factors determine the age of fossils:

• Digging into the earth: Fossils closer to the surface are more recent than the fossils found in deeper layers
• Isotope study: Detecting the ratios of different isotopes of the same element in the fossil material

Evolution by Stages

• Basic events in evolution are changes in DNA during reproduction
• During evolution, organisms adapt their organs or features to new functions. For example, if we talk about feathers, this feature has been evolved for warmth but later adapted for flight
• Comparing the DNA of different species gives a direct estimate of the changes that occurred during the formation of these species
• Rather than natural selection, sometimes artificial selection is followed such as the domestication of plants as crops by humans
• It is assumed that complex organs may have evolved due to the survival advantage of even the intermediate stages

Evolution and Progress

• Darwin’s theory of evolution talks about the evolution of life from simple to more complex forms
• You cannot say that Evolution ‘progresses’ from ‘lower’ forms to ‘higher’ forms
• Instead, it seems that evolution has given rise to even more complex body designs organisms even while the simpler body designs of organisms continue to flourish

Human Evolution

• For studying evolution, tools like excavating, studying fossils and time-dating as well as determining DNA sequences have been used
• A study of the evolution of human beings indicates that all of them belong to a single species that evolved in Africa and spread across the world in stages

Conclusion

In this article, we come to know that the frequency of an inherited trait can change over generations, and it leads to Evolution. Evolution is naturally selected. Genetic drift happens when diversity occurs without any adaptations. The evolution of human beings belonging to a single species evolved in Africa. Variation gives a survival advantage.Based on the various theories of evolution,about 2000 million years ago, the first cellular forms of life appeared on earth. After that, multicellular forms, single-celled organisms and invertebrates were found. The inherited traits in a human being are inherited from the previous generation. On the other hand, the acquired traits are usually developed in accordance with the environment and these traits can not be inherited. Inherited traits occur due to a change in DNA or genes. Consequently, in acquired traits no change in DNA or genes is involved.