1. On the Origin of Species
Darwin’s 5-year voyage began Dec. 1831
He formulated the theory of how species evolved and wrote a 231 page outline in 1844
He continued to gather evidence for another 15 years to support his theory

2. Alfred Russel Wallace (1823-1913)

3. A.R. Wallace
A British naturalist, evolutionist, geographer, anthropologist
He spent many years, from 1848, studying organisms in the Amazon and Rio Negro regions of South America
In 1854 he began his studies in the Indonesian region, collecting 125,600, and discovering more than a thousand new species
He wrote an essay entitled “On the Tendency of Varieties to Depart Indefinitely from the Original Type” and sent it to Darwin

4. Darwin gave the essay to Charles Lyell (geologist) and Joseph Hooker (botanist) to present at the meeting of the Linnaean Society, along with some of his own writings
This prompted Darwin to quickly finish his book
1859 On the Origin of Species was published

5. Natural Selection
The basic premise behind Darwin’s work is that species evolved by the process of natural selection; i.e., the way individuals in an environment are able to survive to reproduce over those individuals who cannot
Traits that lead to characteristics favouring survival and ability to reproduce would be passed on to the next generation

6. Herbert Spencer ( )
Was a sociologist, philosopher, biologist (i.e., polymath) who coined the phrase “survival of the fittest” to describe natural selection

7. More Terms to Know
Adaption = a characteristic that makes a species better suited to survive and reproduce in an environment
Evolution = the result of natural selection, occurring over many years

8. Consolidate the Concepts
Read pages 304 – 307
Do questions on page 307 #1-5, 7, 8

9. Modern Evolutionary Synthesis
This is the field of evolutionary biology studied today
Takes into consideration genetics, botany, entomology, cellular biology, molecular biology, and more
Darwin’s theory focused on the inherited traits of a species over time
Modern scientists focus their work on changes in the gene pool over time

10. Radiometric Dating
A process of determining the age of rocks from the decay of their radioactive elements
An isotope of an atom contains the same number of protons as the atom but different numbers of neutrons, hence has a different atomic mass
A radioisotope is an atom with an unstable nucleus

11. Half-Life Radioisotopes decay at a unique and constant rate
Rate at which decay occurs is counted in half lifes
Half-life = the amount of time it takes a substance to decay to half its original mass
Half-life of 14C is 5730 years
Half-life of 10Be is 1.5 million years and the radiogenic daughter isotope is 10B

12. Fig 1. pg 308

13. Carbon Dating Radioactive carbon-14 has 6 protons and 8 neutrons
A high-energy particle is released changing a neutron into a proton
Daughter isotope is nitrogen (7 protons and 7 neutrons), which is a stable atom
The age of organic material can be determined using carbon dating

14. More About Mutations Mutations can create new or altered traits
Misalignment during cross-over in prophase 1 of meiosis

15. Misalignment of Genes
Mutation from misalignment can result in extra copies of genes or missing genes
If there’s a mutation on the extra gene, it could result in new trait, and still be able to make the protein from the other gene copy
Gametes containing missing genes may not produce a viable zygote

16. Homologous Genes
Closely related species inherit homologous genes – genes with the same nucleotide sequences
Shows there is a common ancestor
The more unrelated the species are, the bigger the difference in nucleotide sequences

17. Homologous Genes

18. Pseudogenes
Vestigial genes that no longer code for a functioning protein
Further evidence of a shared common ancestor
If pseudogenes mutate, no harm is done to the organism

19. Paleontology
The investigation of prehistoric life through the study of fossils
The distribution of fossils helped Darwin formulate his theory of evolution
The location of similar fossils from disparate regions posed a problem until the theory of continental drift, proposed by Alfred Wegener in 1912

20. Plate Tectonics
This is the modern version of continental drift, developed from the 1950s through to the 1970s
The Earth’s outer shell is divided into plates that glide over the mantle (the rocky inner layer above the core)

21. Consolidate the Concepts
Read pages
Do questions on page 313, #1-9