What do you think when you hear this world evolution? Darwin? Creationism? Science? Ecology? Paleontology? Comparative anatomy?. Simply, it can be defined as;
Evolution is a process in which a population gradually alters its physiology and different aspects as to adapt to its ecosystem over the course of time.
BRIEF HISTORY OF DISCOVERY OF EVOLUTION
Its something gradual, continuous and painstakingly slow. This idea was first proposed by Greeks such as Aristotle that the living beings change with time. But the modern evolution theory begins with Lamarck (Who gave the hypothesis of inheritance of Acquired characteristics) who said that the living organism acquire certain traits during their lifetime which then is genetically transferred to its offspring. Like if a Blacksmith hammers iron everyday he will have strong arm muscles and this trait would be inherited by its offspring. Although it is completely wrong. But this gave way to something greater. And that is Darwin.
ROLE OF DARWIN
I wont bother you with facts about his life at general. So lets get down to brass tacks. He while visiting South America on a ship called “Beagle” observed different life forms there. He collected different flora and Fauna there. Studied a bit. And soon he discovered islands called Galapagos Islands where he found similar animals albeit with some different features. He discovered that as once these islands were in close proximity of South America similar organisms were distributed here. But as it went away and away the islands became kind of secluded and isolated. That’s when they began to EVOLVE . And over a long stretch of time they were different from their counterparts in South Africa which had been evolving quite differently according to their respective environment. That was a BREAKOUT, a scientific triumph. What later happened and the books he wrote are out of scope of this article. So lets talk about what the Evolution means after all.
SOURCES OF EVOLUTION
Evolution is based on the concept of Natural Selection. Lets explain it with a simple example. We have a adorable mouse couple one .They are black and white. They have 3 babies. One is black , other is brown (Mutation occurred here) and the third is white . The white is more susceptible to predation and will be killed earlier. Followed by Black. And brown will be last due to its better camouflage. Similarly if we have a large group of mice with these colors. White population will diminish faster. Followed by Black. As resources are limited these organism will also compete. Over time this brown mouse will become more common. That’s how it works. Different traits will be introduced and those individuals with desirable characters will dominate. I mentioned Natural selection and Mutation here. These along with genetic drift and gene flow are the primary sources of evolution. Genetic drift can be explained as effects of environmental factors on a population that occur randomly. Lets progress with the previous example. The mouse pair had a mutant baby which was brown. If things had went well,it would have survived and reproduced brown would probably had become more popular. But what if a cat finds that mouse and gobbles it up ( Eh heh like Tom and Jerry). That’d be called genetic drift. Something random that has effect on a population. To explain gene flow. Lets say that the black mouse from a certain population meets another population of mice where black trait is absent. It reproduces with a mouse from that group and this way introduces a new dominant trait to that group of mice. Its gene flow or rather flow of genes.
Note: These traits are represented by alleles of chromosomes. So mutation means mutation is some gene.
I would now recommend you to read this page and resume this article, its almost over.
Don’t worry its precise. And then after Gradual evolution these eukaryotes became multicellular entities over billion years. Tracing over lineage first came fishes, then amphibians, then reptiles and finally mammals. And us. I would like to end this article with this following video.