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Tracing Evolutionary Relationships

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The transfer of traits from one generation to the next is known as heredity, also known as inheritance or biological inheritance. Whether by asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic makeup of their parents. Variations between people can accumulate through genetics and lead to the natural selection-driven evolution of species. In biology, genetics is the study of heredity.

Evolution is the gradual change in the inherited traits of biological populations over many generations. These traits are the expressions of genes that are passed down through reproduction from parent to offspring. Because of mutation, genetic recombination, and other causes of genetic variation, different traits frequently occur within a population. This variety is subjected to evolutionary processes like natural selection (including sexual selection) and genetic drift, which cause some traits to become more or less prevalent within a population. This is when evolution happens.

Evolutionary Relationships

A common ancestor between two different organisms can be inferred from essential traits that they share. These similarities can be used to define evolutionary connections. In order to establish evolutionary relationships and identify patterns amongst organisms, an evolutionary tree or phylogeny is crucial. The following traits are helpful in determining evolutionary relationships:

  • Breeding behavior
  • Geographical distribution
  • Cladistics
  • Structural similarities
  • Biochemistry

Evolution and Classification

According to the theory of evolution by natural selection, genetic variety and the principle of the fittest lead to changes in organisms through time. Modern biology is built on this notion, which is supported by data from a wide range of scientific fields.

Organisms can be categorized as a technique of grouping them according to similarities. The Linnaean system, created by Swedish scientist Carl Linnaeus in the 18th century, is the most popular classification scheme. The Linnaean system is based on the binomial nomenclature concept, which gives each species a two-part name. The genus appears in the first half of the name, and the species appears in the second.


Typically, when an organism dies, its body will degrade and disappear. The body, or at least some of it, may occasionally be in an environment that prevents decomposition, completely. For instance, a dead insect that is entangled in heated mud will not break down rapidly, the mud will gradually solidify and preserve its shape. the appearance of an insect’s body parts. All of these traces that have been preserved of living creatures are referred to as fossils.



Fossils are Helpful in Developing Evolutionary Relationships

Thousands of extinct animals’ fossil remains have been found and researched by paleontologists over the years. This fossil record demonstrates that numerous extinct species had different forms than any of their living relatives. The record also illustrates how organisms changed over time in succession, allowing us to discern how they changed from one form to another.

When an organism passes away, it is typically broken down by other living things and by weathering processes. When an organism dies, certain of its body parts, especially the hard ones like shells, teeth, or bones, are sometimes maintained because they are buried in mud or otherwise shielded from the environment and decomposing organisms. They eventually become petrified and are permanently preserved with the rocks they are lodged in.

The earth was formed over 4.5 billion years ago, according to techniques like radiometric dating, and the earliest fossils resemble creatures like bacteria and cyanobacteria. These microbes have fossils in rocks that date back more than 3.5 billion years. The earliest animal fossils, which are little, soft-bodied organisms resembling worms, are from the Ediacaran fauna and are almost 700 million years old.

The earliest vertebrate fossils indicate that they initially appeared about 400 million years ago, while the earliest mammals arrived about 200 million years later. The fossil record isn’t comprehensive, though. Paleontologists have only managed to retrieve and study a very small portion of the fossils that are still present on Earth, and in those few instances, the succession of forms has only occasionally been precisely rebuilt. The evolution of the horse is one illustration.

Carbon Dating

One of the most common techniques in archaeology for dating organic artifacts up to 50,000 years old is carbon dating. This approach is predicated on the notion of the carbon-14 isotopes’ long-term radiative degradation. Physics has shown that the pace at which radioactive compounds degrade depends on the atomic number and mass of the atoms that are decaying. The ratio of radioactive isotopes to the estimated initial concentration of these isotopes at the moment of the organism’s death can be used to calculate the approximate age of the decaying material using this constant. According to scientists, there hasn’t been much of a shift in the ratio of carbon-12 to carbon-14 isotopes in the atmosphere, therefore their connection should mostly remain unchanged.

Importance of Carbon Dating

Different civilizations and faiths use various dating techniques. Absolute dating, or the age of the substance prior to the present, is a particularly useful feature of carbon-14 dating. This implies that it can be applied and evaluated against dates everywhere in the world. In fact, it is still the primary method for dating the last 50,000 years and is regarded as the “most important development in absolute dating in archaeology.” Scientists seek to use this instrument to solve the puzzles surrounding the origin of mankind, the duration of his existence, his travels, and the construction of a timeline of human history.

DNA Sequence Determination

The nucleotide sequence of DNA is its most crucial component. Utilizing DNA polymerase’s enzymatic properties allows for the determination of DNA sequences. All DNA polymerases need a primer to start the synthesis process. A single primer is hybridized into the DNA strand that has to be sequenced to start the sequencing reaction. This primer-initiated synthesis starts out exactly like a PCR. The primer used to start the synthesis process can either be a primer used in PCR to amplify the DNA or it can be complementary to the vector in which the DNA is cloned. The fact that every newly generated molecule will have the same sequence is crucial for sequencing DNA. DNA polymerase is combined with deoxynucleoside triphosphates to lengthen the primer. All of the newly expanded molecules would be complementary to the complete template chain if these two elements alone made up the reaction mixture, just like in PCR. In addition to the four deoxynucleoside triphosphates (dNTPs), the sequencing reaction also includes 2′,3′-dideoxynucleoside triphosphates, or ddNTPs (ddGTP, ddATP, ddTTP, or ddCTP).


Excavation is the act or process of digging, particularly when a specified object is being taken out of the ground. To find artifacts and fossils, archaeologists conduct excavations.

Although there are many different kinds of excavation, they all involve making holes in the ground. Excavation is necessary for mining coal, gold, or diamonds, and it is frequently necessary to perform some excavation prior to pouring a foundation for buildings and dwellings. Excavare, “to hollow out,” with its roots in ex-, “out,” and cavare, “to hollow,” is where the Latin word excavation, which means “a hollowing out,” comes from.

Classification of Excavation

A common method of classification is by the material being excavated:

  • Topsoil excavation: In order to do this, the exposed layer of the earth’s surface must be cleared of any vegetation or decomposing debris that would cause the soil to become compressible and hence unfit for supporting structural loads. Although the depth varies from site to site, it typically ranges from 150 to 300 mm.
  • Earth excavation: This entails removing the soil that lies immediately below the topsoil. The excavated material, sometimes known as “spoil,” is frequently heaped up and used to build foundations and embankments.
  • Rock excavation: This is the removal of material that cannot be dug up without the aid of specialized excavation techniques like drilling (either manually or with large gear) or explosive blasting.
  • Muck excavation: This is the process of removing overly damp debris and soil that cannot be piled.
  • Unclassified excavation: This involves removing a combination of the aforementioned components, typically in situations when it is challenging to tell which materials have been present.

FAQs on Tracing Evolutionary Relationships

Question 1: What are the tools for tracing evolutionary relationships among species?


Tools that are responsible for tracing evolutionary relationships among species are-

  • Studying the similarities and differences between several species to identify traits from a common ancestor.
  • Evidence for the emergence and diversification of species from a common ancestor can be derived from studying fossil remains of ancient forebears.
  • It is possible to identify shared genes and genetic material in related creatures by comparing the DNA sequences of other organisms.

Question 2: What is carbon dating?


Carbon dating is one of the most popular methods in archaeology for determining the age of organic artefacts up to 50,000 years old. This strategy is based on the idea of the long-term radiative destruction of the carbon-14 isotopes. Physics has revealed that the pace at which radioactive materials disintegrate depends on the atomic number and mass of the atoms that are decaying. This constant can be used to determine the approximate age of the decaying material by comparing the ratio of radioactive isotopes to the estimated initial concentration of these isotopes at the time of the organism’s death.

Question 3:  What is excavation?


Excavation is the act or process of digging, particularly when a specified object is being taken out of the ground. To find artifacts and fossils, archaeologists conduct excavations. Although there are many different kinds of excavation, they all involve making holes in the ground. Excavation is necessary for mining for coal, gold, or diamonds, and it is frequently necessary to perform some excavation prior to pouring a foundation for buildings and dwellings.

Question 4: Define DNA Sequence Determination.


The most important part of DNA is its nucleotide sequence. DNA sequences can be determined by using the enzymatic capabilities of DNA polymerase. A primer is required by all DNA polymerases to initiate the synthesis process. The sequencing procedure is initiated by hybridising a single primer to the DNA strand that has to be sequenced. Just like a PCR, this primer-initiated synthesis gets underway. The primer used to initiate the synthesis process can be either complementary to the vector in which the DNA is cloned or it can be a primer used in PCR to amplify the DNA.

Question 5: What are the homologous organs? How do they help in providing evidence for organic evolution?


Homologous organs are defined as having distinct activities but sharing a common embryogenic origin, embryonic development, and interaction with surrounding organs. They represent a tight bond between their owners. For instance, although the structure and function of a human forelimb, a bird’s wing, a horse’s leg, and a seal’s flipper may appear to differ from one another, they are all built using the same pentadactyl structure, with the same number of bones, muscles, blood vessels, and nerves arranged in the same pattern and developing similarly. Therefore, the most logical theory is that all of these animals’ forelimbs were passed down from a single ancestor over a very long time.

Question 6: What are fossils? How do they act as evidence for organic evolution?


Fossils are the skeletal remains of extinct plants, animals, or other species that have been petrified. When plants or animals are buried in mud and soil, they are created. By leaving the hard bones and shells, the soft tissues decompose quickly. Over time, sediment accumulates on top of the bones and shells, hardening to form rock.  The history of evolution can be directly demonstrated by fossils.  Scientists use fossils to compare modern and historical creatures.  An estimate of the occurrence of an organism during a specific period can be gained from calculating the age of fossils.

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Last Updated : 06 Dec, 2022
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