The concept of the origin of life is a crucial one in that different groups of people have a different perspective of how life came about. Some group of people says there is a divine creator that created all living things. Even with that different groups, there are different views of how that divine creator created life. Some also said living things came from nonliving things, that is protons and other subatomic particles. Another group said the whole universe was in a big bang that blasted to release its content. They said all the things we see around were in that big bang. All the above groups have a lot of questions to answer. After the origin of life, arose the concept of evolution. The idea that living things came from a common ancestor and that we keep changing from primitive organisms to higher class organisms. Some scientists say humans came from apes monkeys and some scientists also say life generally comes from water. There are many theories of the origin of life and the concept of evolution. Let us see how best we digest this whole issue.
WHAT IS EVOLUTION?
Evolution is the gradual and orderly change in the form of an organism over a period that arises from a combination of both environmental and biological factors (mutation). Evolution arose from the fact that living organisms want to adapt to the challenges their environment poses to them, or the desire by organisms to explore new ways of living in their habitat. These factors lead to the change in form or the development of special features.
IDEAS OF EVOLUTION
There are different ideas on how life came about and how we are evolving. There are the five main ideas of evolution. These ideas are based on the thoughts of people without any proof.
THE IDEA OF DIVINE INTELLIGENCE AND CREATOR
This idea of evolution is based on the fact that there is a supernatural force somewhere that created all things into being in the beginning. This idea holds for all creatures in the universe. This divine creator gave life to all living creatures, therefore created all living and nonliving things. HE is in control of whatever happens in the universe. This idea of the origin of life is purely religious and does not have any substantial evidence of the creator's existence from a scientific point of view.
ANCIENT GREEK, CHINESE, EGYPT, AND ROMANS IDEAS
Various groups of people had different ideologies on the origin of life and evolution.The ancient Chinese believed that in the beginning fire, gold, wood, sand, and water were originally present. These five elements interact with each other positively and negatively to bring about life from a single source.The Egyptians and Romans also believed that some divine force somewhere created life in stages. The idea is almost the same as that of the idea of divine intelligence.
LAMARCK'S THEORY OF EVOLUTION
Jean-Baptiste Lamarck was a French naturalist, who believed all living organisms came from a common ancestor. In his theory, he made mention of three ideas of evolution that were later found to be false. All organisms have an inbuilt power that causes them to progress from a simple state to a complex state. All organisms have an inner force that causes the performance of the action in them, and this force is sufficient enough to meet the needs created by the changing environment. Characters are acquired through the use of body parts in life can be inherited by the succeeding generations. Those that are not used get lost and are not part of inherited characters in the generations to come. This idea of evolution is part of history since they are proven to be false.
CHARLES DARWINS IDEA OF EVOLUTION
Charles Darwin was a British naturalist who proposed the theory of natural selection. According to him, resources became limited in the environment, organisms struggle for their survival and that of their offspring. Those that adapted and survived are the fittest from that species. The fittest individual survives and represents the species in the generations to come. Those that are not able to survive the environmental pressures die off. This idea from Darwin earned him the title the father of genetics.
MODERN IDEA OF EVOLUTION
In present days evolution is seen from a different angle. Present days scientist has concluded that evolution is as a result of five factors, which works for hand in hand to bring about the total or partial change from a simpler state to a complex state of the organism. These are gene mutation, natural selection, genetic recombination, change in chromosomal number and structure, and reproductive isolations. Researches made us understand that these five factors work alongside migration, mutation, and change to bring about the evolution of organisms and speciation.
EVIDENCE OF EVOLUTION
The ideas above are people's thoughts of how life and evolution came about. Aside from these ideas, there are actual things that show all living things have evolved. All organisms once existed in different forms and have change into a better form in the present day.
EVIDENCE FROM FOSSIL RECORDS.
Fossil is simply the remains or impressions of living organisms that have been preserve from ancient days till now. From these objects gathered, it shows without any agreement that some of the organisms that existed in the past are no more present in our present days. Some of these organisms are still existing but in different form and has been modified to better adapt to the present environment. Either they are smaller or bigger than those in the ancient days. The fossil materials there are in a form of shells, bones, woods, teeth, and pollens. These are the direct evidence of the evolution we have today. From this evidence, Leonardo Da Vinci concluded that fossils are the remains of organisms that existed in the past. After this conclusion there arose the idea of the location of these fossils. Most of the fossils that we're found on mountains were fish-like creatures. Base on these, some scientists concluded that life came out of water.
EVIDENCE FROM COMPARATIVE ANATOMY
Comparative anatomy is the study of the basic similarities that exist between members of the same phylum or class of organisms. For instance,The existence of Homologous structures. Fishes, buts, cuts, horses, birds, and humans have limbs that look similar but are used for different purposes. Some use theirs to swim, fly, run and walk. This shows that all these animals came from the same ancestors but evolved through different lines. That is why they all have similar structures that are used for locomotion.
EVIDENCE FROM COMPARATIVE EMBRYOLOGY
Comparative embryology is the study of how the embryos of different species are formed in stages and the similarities between them. When we take a critical look at the development of the embryo of fishes, reptiles, birds, and mammals, we find out that the initial stages of development look the same. After some time in their development, they start to look different. This is evidence that shows that all living things were from a common ancestor. That is why they look alike at the initial stages of embryonic development.
EVIDENCE FROM PHYSIOLOGY AND BIOCHEMISTRY
Physiology is the study of how the physical structures of an organism work. Whilst biochemistry is the study of the chemical composition of living structures. From these two branches of science, we can establish some evidence of evolution. The existence of similar hormones and enzymes that perform almost the same function in all vertebrates, shows that all vertebrates evolved from a common ancestor that uses such hormones and enzymes for life processes. The constituent of the protoplasm ( cell component) is also evidence that evolution existed. The composition of almost all cells has a lot of things in common. Water, lipid, carbohydrates, and other cell components show that all cells originate from one ancestor. The study of chromosomes revealed that the genetic material content, composition, and structure show that all living cells have great similarities in their chromosomes. This also indicates that all living things inherited chromosomes from a common ancestor.
EVIDENCE FROM TAXONOMY
Taxonomy is the science of classifying and naming organisms base on common characteristics. Scientific names are given to organisms base on their ancestral descent. Organisms with the common feature are grouped into particular taxon because they come from a common ancestor. For example, mammals, reptiles, honey fish, amphibians, and birds are in the same phylum ( phylum Chordata) because they have a notochord as common characteristics. This proves that living organisms in any taxa of classification are from a common ancestor.
The concept of the origin of life and evolution seems to be controversial because the evidence of their existence is too hard to believe and accept as true, exceptionally to the layperson. The layman continues to ask a lot of questions. For example, wherefrom the subatomic particles that evolved through series of processes to form living things. The scientist, on the other hand, tries to ask the question that, where is this divine intelligence and creator that created living things. The question goes on and on whether life was created by a creator or life came out of subatomic particles, the fact is that after the creation or evolution of life, all living things have changed their form to adapt to the changes of the environment.
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