Biology 11. Unit 1: Evolution Lesson 1: Why Evolution??. By the end of the lesson you should be able to: Explain why DNA is so important to the theory of evolution State the men of evolution and what they contributed to the developing theory
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Unit 1: Evolution
Lesson 1: Why Evolution??
Before we can truly understand evolution we need to understand DNA
DNA = deoxyribonucleic acidDNA and Evolution
Double helix understand DNA
Sugar phosphate backbone
4 nitrogenous bases (ATCG)
Complimentary base pairing
(A = T; C Ξ G)Characteristics of DNA
DNA is unique to each organism understand DNA
If DNA changes the organism changes
Evolution is the change of populations of organisms over time
THEREFORE the DNA must be changing over time if the organisms are changing!DNA and Evolution
- the change through time
- all living and non-living things change over time
This is a picture of what Alberta used
to look like. It was a Carboniferous Swamp that existed 300 mya…this is where our fossil fuels come from.
Evolution is just a theory! understand DNA
It has a large body of evidence that is very widely accepted and has been scientifically tested for many years
Its more than just a hunch or guessEvolution as a Theory
Proposed understand DNAInheritance of Acquired Characteristics
or “Theory of Use-Disuse”
First person to propose a mechanism for evolution, although wrong, he really challenged peoples long held ideasJean Baptiste Lamarck
If an organism uses a structure a lot and so do its ancestors, over time that structure develops better. Ex: Giraffes
Why is this wrong?Use-Disuse Theory
Darwin’s 13 varieties of finches: ancestors, over time that structure develops better. Ex: Giraffes
Darwin contributed two main ideas: ancestors, over time that structure develops better. Ex: Giraffes
1. Evolution, which he called “Descent with Modification.”
2. The mechanism of evolution: Natural Selection
Today we refer to Darwin’s theory as “Gradualism”Darwin’s Main Ideas
From this overabundance, there is a “struggle to survive” among the offspring
In every population, there are variations in all traitsDarwin’s Theory:Descent with Modification
Those offspring with variations that make them better adapted to their environment are more likely to survive (Survival of the Fittest)
Those offspring who survive will mate with others who possess the favorable trait and this trait will be passed on to future generations (Natural Selection)Descent with Modification
- The answer was in Gregor Mendel’s work on pea genetics
2. He could not show a single example of evolution occurring today, ie evolution in progress.
- He missed a good example right under his nose: the Peppered Moths of the Manchester Forest.