E.Q: What is evolution

Evolution- gradual change over time

• Change happens in a population NOT an individual • Modern organisms have descended from ancient organisms (common ancestor)

Evolution is not linear, it consists of

many branches

The history behind the theory

Hutton and Lyell!

•  Uniformitarianism- processes going on today, are responsible for changes in the past.

Georges Cuvier

Father of comparative

anatomy! !

Jean-Baptiste Lamarck

1744-1829

•  1st scientist to publicly advocate evolution

• Claimed that adaptation was the mechanism for evolution

Darwin 1809-1882 Father of Evolution

•  Took trip around the world in a ship called the H.M.S Beagle • He got to the Galapagos

Island where he studied finches • Depending on location

finches had beaks adapted to their food source

Evidence for Evolution

1.  Biogeography- geographical distribution of organism can help us reconstruct evolutionary history

2.  Fossils- Fossils show a series of organisms that have lived on earth and how they have changed

Evidence for Evolution

3. Embryology- All vertebrate embryos have the same structures during development 4. Vestigial Structures- structures in the body that are present but no longer function

Evidence for Evolution

5. Homologous Structures- Similar bones with different functions 6. DNA- All organisms have the same nitrogenous bases A, T, G and C

Vocabulary • Gene pool- total number of genes of every individual in an

interbreeding population • Organisms- one individual in a population •  Population- all members of a species within a geographically

defined area •  Species – a group of organisms that can breed and produce

fertile offspring •  Speciation- any process where one species splits into 2 or more

species • Adaptation- anything that better fits a population for its

environment or increases the ability of its members to survive and successfully reproduce

Mechanisms for Evolution

Natural Selection

A large portion of the

population dies before they

can reproduce

When they die their genes die

with them

Only those who survive

and reproduce

contribute to the gene pool

Gene pool-total number of genes

of every individual in an interbreeding population.

Fitness-organisms ability to

survive and successfully reproduce

Mutations

• A random change in a DNA base sequence

Gene flow

• also known as gene migration is the transfer of alleles or genes from one population to another

Genetic drift

•  change in a gene pool due to a random event 

Sexual Reproduction

•  Sex can introduce new gene combinations and alter frequencies if there is assortment in mating