B I O L O G Y L I T E R A T U R E
S O P H I E A D E L A I D E
What is evolution?
In Biology, evolution refers to change in characterics of organisms over several generation. This theory is based on the idea that species are all related to each other and gradually change over time to adapt to their surroundings. Evolution relies on the genetic variation that all members of a population has, which affect their physical characteristics. Some of these characteristics will play in favour of the organism, and some the opposite. Eventually, the organisms having unwanted traits will start to die off, and genes that are passed down to off spring are desired genes.
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The theory of evolution suggests that all life forms on Earth long ago came from one organism, however began to increase their population by creating off spring. As the population increased, some of that off spring decided to go separate ways in order to seek shelter, or better food. Eventually, they decided to stay in their new habitat, and over generations began to develop characteristics that would help them survive more in their ecosystem. Eventually over billions of years the all begin to branch off.
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What is the difference between fact and theory?
In the scientific world, facts are something that you know based on a real observation. If you are trying to test something to learn a new fact, you would have to test hat fact by creating and recreating a scenario repeatedly to test if your hypothesis is true. If you are able to create a valid experiment and observe it to prove something, that proven thing is a fact. However, something observations are made however cannot necessarily be replicated and tested in a way that is valid for the scientific world. In this case, we create theories which are more vague and cannot really be tested.
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How to different species evolve?
A long time ago, there was only one living organism on Earth. That organism however began to create lots of offspring, rapidly increasing in population. Eventually they began to separate and develop into many different animals. This goes the same with different species. A population of the same species are very likely to separate into many different groups depending on where they chose to live, hunt or breed. Eventually those two groups will live in two or more different habitats, with different environmental conditions. Because of that, as they begin to create offspring, a process called natural selection occurs in which the animals that have characteristics that are more fit for their environment are the ones that survive long enough to create off spring. Eventually the ones with that desired gene become more and more common. After many generations they become an entirely different separate species suited to thrive in their habitat.
J O U R N A L 1 : E V O L U T I O N
W E E K 2 : D A R W I N ' S T H E O R Y
What is Darwin's Theory?
Charles Darwin was a naturalist that studied variation and diversity in various organisms, through out his five-year voyage around the world, subsequently publishing his findings in a book called 'The Origin of Species'. Darwin suggests that all life and diversity on Earth evolved from simple life forms, and share one common ancestor billions of years ago, which were most likely bacteria. Overtime, the single celled organisms evolved into bigger, more complex beings as the Earth's environment changed. The organisms rapidly increased in population and began taking over both land, and water diverging into many different species as they ventured into different ecosystems, which required different adaptive traits to help them survive.
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What is natural selection?
Darwin's theory suggests that evolution happens due to natural selection, which happens when organisms produce offspring that occasionally experience a mutation in their DNA, resulting in a unique trait. Those traits can either help or hinder their survival, depending on their ability to utilise the trait in their environment. If the trait helps them survive, then the organism will live to pass on that gene to their offspring, which will also survive. If their trait is a disadvantage, then the organism will die with less chances of passing on its gene to offspring. Eventually, the desired traits will flourish, and the other ones will die off.
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What is adaptation?
An adaptation is a mutation, or a genetic change in organisms, giving them traits that aid their survival in their specific environment as a result of evolution. Because the traits are good, natural selection allows organisms to pass them down to future generations, so more and more organisms will inherit the trait. Eventually the organism will flourish with the help of the trait, eventually making it an entirely different species characterised by that specific trait.
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