What Is Evolution?
Evolution is the theory that organisms change over time because their genetic coding changes (DNA). Since the beginning of time living organisms have been given two choices : to adapt or die. The scientific theory of evolution was proposed by Charles Darwin. Now most believe that when someone refers to something as a theory it means that it is just an idea with no proof, WRONG! A theory needs to have a large amount of evidence, been scientifically tested for many years and be widely accepted, like the theory of evolution. However, evolution was not new concept when Charles proposed it. There were people before him, like Erasmus Darwin and Jean Baptiste Lamarck, that helped to shape the revolutionary theory that we know of and keep studying today.
Firstly, there was Jean Baptiste Lamarck who was a French naturalist. He proposed the theory of " Inheritance of Acquired Characteristics" or more commonly known as the theory of "Use and Dis-Use". He was not the first to propose a theory related to evolution but he was the first to propose a mechanism for evolution. Although wrong, he challenged people's long held ideas. Around the same time, Erasmus Darwin was an english physician who believed that organisms evolved over time. However, he could not figure out how. Therefore, he did not widely spread his ideas but instead told his grandson , Charles Darwin. In doing so, greatly influencing the young child's mind. Which leads us back to the famous Charles Darwin.
Charles Darwin was profoundly influenced by his grandad's work. After Charles started to neglect his studies at university where he was studying to become a doctor, he found the lectures uninteresting and could not stand the sight of blood. His father became deeply annoyed with him for neglecting his medical studies. so therefore sent him to become a priest. However, Erasmus Darwin knew of his grandson's interest in nature and therefore interfered by suggesting he go on a two year voyage on The Beagle as a young naturalist. His voyage ended up lasting around five years. During the long voyage Darwin made careful notes and observations of the various organisms that he saw and studied including finches in the Galapagos Islands. Charles was very puzzled by the diversity of life on the islands. He noticed that there were some birds that looked to be related but when looked upon closely were slightly different. He observed 13 different varieties of finches, he knew they were all related, but they all slightly differed in physical characteristics from island to island. When he got back home he did not publish his work right away, instead he continued to gather more evidence and study. Twenty-three years later Charles published all his work in a book called "The Origin of the Species".
In this book Darwin contributed two main ideas:
1. Evolution, which he called “Descent with Modification”
2. The mechanism of evolution: Natural Selection
We refer to his theories as "Gradualism". When he first published his ideas Charles Darwin was first greatly ridiculed. But he slowly convinced the scientific community. He stated that offspring with variations in some traits that make them better adapted were more likely to survive than offspring born without these mutations. The better adapted offspring will henceforth mate and pass the favourable traits to the next generation and so forth. However, Charles could not explain how the change (evolution) happened nor provide examples of active evolution.
Moreover there are five mechanisms of changing the gene pool (Microevolution):
1. Natural Selection: the "fittest" survive and therefore pass on their genes to the next generation.
2. Mutations: when the DNA in an organism changes, change can be good, bad or neutral.
3.Genetic Drift: a random event changes the gene pool.
4. Gene flow: how the genes "transfer" from one pop. to another.
5. Non-Random Mating: include harems, assortative mating, and sexual selection.
To summarize, microevolution is a change in the genes within a population. Thus, making the species better adapted (or fittest) to their environment.
Macroevolution is similar yet different. There are two types of speciation (making a new species):
1. Divergent Evolution: when a part of a population becomes isolated in a "new area" and adapt to the new environment.
2. Convergent Evolution: when 2 unrelated species move into the same area and adapt > therefore they start to develop similar characteristics.
Nowadays, we are much more informed in the subject of evolution. We know that there are two types of evolution: Micro and Macro Evolution. MicroEvolution is the changes in DNA of one species while MacroEvolution is the changing of one species to another (completely changing the DNA structure of the organism). Micro and Macro evolution are the basics of the Theory of Evolution.
Firstly, there was Jean Baptiste Lamarck who was a French naturalist. He proposed the theory of " Inheritance of Acquired Characteristics" or more commonly known as the theory of "Use and Dis-Use". He was not the first to propose a theory related to evolution but he was the first to propose a mechanism for evolution. Although wrong, he challenged people's long held ideas. Around the same time, Erasmus Darwin was an english physician who believed that organisms evolved over time. However, he could not figure out how. Therefore, he did not widely spread his ideas but instead told his grandson , Charles Darwin. In doing so, greatly influencing the young child's mind. Which leads us back to the famous Charles Darwin.
Charles Darwin was profoundly influenced by his grandad's work. After Charles started to neglect his studies at university where he was studying to become a doctor, he found the lectures uninteresting and could not stand the sight of blood. His father became deeply annoyed with him for neglecting his medical studies. so therefore sent him to become a priest. However, Erasmus Darwin knew of his grandson's interest in nature and therefore interfered by suggesting he go on a two year voyage on The Beagle as a young naturalist. His voyage ended up lasting around five years. During the long voyage Darwin made careful notes and observations of the various organisms that he saw and studied including finches in the Galapagos Islands. Charles was very puzzled by the diversity of life on the islands. He noticed that there were some birds that looked to be related but when looked upon closely were slightly different. He observed 13 different varieties of finches, he knew they were all related, but they all slightly differed in physical characteristics from island to island. When he got back home he did not publish his work right away, instead he continued to gather more evidence and study. Twenty-three years later Charles published all his work in a book called "The Origin of the Species".
In this book Darwin contributed two main ideas:
1. Evolution, which he called “Descent with Modification”
2. The mechanism of evolution: Natural Selection
We refer to his theories as "Gradualism". When he first published his ideas Charles Darwin was first greatly ridiculed. But he slowly convinced the scientific community. He stated that offspring with variations in some traits that make them better adapted were more likely to survive than offspring born without these mutations. The better adapted offspring will henceforth mate and pass the favourable traits to the next generation and so forth. However, Charles could not explain how the change (evolution) happened nor provide examples of active evolution.
Moreover there are five mechanisms of changing the gene pool (Microevolution):
1. Natural Selection: the "fittest" survive and therefore pass on their genes to the next generation.
2. Mutations: when the DNA in an organism changes, change can be good, bad or neutral.
3.Genetic Drift: a random event changes the gene pool.
4. Gene flow: how the genes "transfer" from one pop. to another.
5. Non-Random Mating: include harems, assortative mating, and sexual selection.
To summarize, microevolution is a change in the genes within a population. Thus, making the species better adapted (or fittest) to their environment.
Macroevolution is similar yet different. There are two types of speciation (making a new species):
1. Divergent Evolution: when a part of a population becomes isolated in a "new area" and adapt to the new environment.
2. Convergent Evolution: when 2 unrelated species move into the same area and adapt > therefore they start to develop similar characteristics.
Nowadays, we are much more informed in the subject of evolution. We know that there are two types of evolution: Micro and Macro Evolution. MicroEvolution is the changes in DNA of one species while MacroEvolution is the changing of one species to another (completely changing the DNA structure of the organism). Micro and Macro evolution are the basics of the Theory of Evolution.
Is Evolution True?
This is one of the more frequently asked questions in the scientific community. It all comes down to opinion and if there is a sufficient amount of evidence (in one's opinion).I believe that microevolution is true yet I am not so convinced that macroevolution is.
There are 4 concrete pieces of evidence that back up evolution:
1. Fossil Evidence
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
Fossil Evidence and Comparative Anatomy are the first two methods of evidence for the Evolution Theory. When comparing fossil evidence they look at homologous structures in fossils to species alive today. Similarly, in comparative anatomy they compare homologous organs (not just bones) to species alive today. When organisms have similar bone structures they believe that therefore both species must have a common ancestor. To me these are not the most convincing pieces of evidence , so therefore i don't necessarily believe in macroevolution.
However comparative embryology and molecular evidence provide more solid and accurate evidence.
An embryo always expresses the most basic genes of the species, therefore when you compare embryos it is easier to see relationships between different species by comparing their embryos. This can tell us more accurately if a species is related and has gone through the process of evolution.
Likewise, molecular evidence is the most accurate evidence of evolution. By looking at the DNA of two species we are clearly able to tell if the species are related by their similar genetic coding. Which can prove that both species had a common ancestor or are part of the same species then went through evolution.
To conclude, in my opinion microevolution has more concrete evidence and is more believable than macroevolution which does not have that much evidence (lack of intermediate fossils) and seems less likely and more sci-fi. Until there is more concrete evidence on macroevolution i will not be able to completely believe that one species can completely change to become a whole different species (example: apes to humans).
There are 4 concrete pieces of evidence that back up evolution:
1. Fossil Evidence
2. Comparative Anatomy
3. Comparative Embryology
4. Molecular Evidence
Fossil Evidence and Comparative Anatomy are the first two methods of evidence for the Evolution Theory. When comparing fossil evidence they look at homologous structures in fossils to species alive today. Similarly, in comparative anatomy they compare homologous organs (not just bones) to species alive today. When organisms have similar bone structures they believe that therefore both species must have a common ancestor. To me these are not the most convincing pieces of evidence , so therefore i don't necessarily believe in macroevolution.
However comparative embryology and molecular evidence provide more solid and accurate evidence.
An embryo always expresses the most basic genes of the species, therefore when you compare embryos it is easier to see relationships between different species by comparing their embryos. This can tell us more accurately if a species is related and has gone through the process of evolution.
Likewise, molecular evidence is the most accurate evidence of evolution. By looking at the DNA of two species we are clearly able to tell if the species are related by their similar genetic coding. Which can prove that both species had a common ancestor or are part of the same species then went through evolution.
To conclude, in my opinion microevolution has more concrete evidence and is more believable than macroevolution which does not have that much evidence (lack of intermediate fossils) and seems less likely and more sci-fi. Until there is more concrete evidence on macroevolution i will not be able to completely believe that one species can completely change to become a whole different species (example: apes to humans).
A more concrete piece of evidence
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Not a great piece of evidence
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Survival of The Sickest
Chapter VII:Why You and Your iPod Must Die
Dichotomous Diagram
A dichotomous key is a tool to help characterize and categorize living organisms based on their traits.
This is an example of a dichotomous key:
This is an example of a dichotomous key:
The "organisms" that need to be categorized
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Graph showing all the possible links
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The Dichotomous Key
