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
Unit 1: Evolution
Lesson 1: Why Evolution??
By the end of the lesson you should be able to:
Before we can truly understand evolution we need to understand DNA
DNA = deoxyribonucleic acid
Sugar phosphate backbone
4 nitrogenous bases (ATCG)
Complimentary base pairing
(A = T; C Ξ G)
DNA is unique to each organism
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!
- 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!
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 guess
Proposed Inheritance of Acquired Characteristics
or “Theory of Use-Disuse”
First person to propose a mechanism for evolution, although wrong, he really challenged peoples long held ideas
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?
Darwin’s 13 varieties of finches:
Darwin contributed two main ideas:
1. Evolution, which he called “Descent with Modification.”
2. The mechanism of evolution: Natural Selection
Today we refer to Darwin’s theory as “Gradualism”
In nature, more offspring are produced than can possibly survive
From this overabundance, there is a “struggle to survive” among the offspring
In every population, there are variations in all traits
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)
- 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.