1. Scientific Contributions
To a Theory of Evolution
8.1

2. Scientific theory Ask Questions Scientific Hypothesis
make observations
Scientific Hypothesis
possible explanation for observations
Hypotheses are tested
experiments, models, observations...
consistently lead to successful predictions and explanations
Scientific theory

3. Where did we come froM?
Many of the earliest ideas of life were strongly influenced by religion and philosophy!
These ideas suggested that all forms of life existed, unchanged, since their creation

4. When we think of evolution - we think of Darwin.
But, many scientists came before Charles Darwin.
He put all the pieces together and had the courage to publish it...

5. John Ray Late 17th century
- early classification of plants and animals based on morphology (physical traits)
- noted how living things were adapted to their environment
- concluded that this was God’s design and NOT evolutionary change

6. Carl Linnaeus King of Classification!
(Remember the diversity of life unit?)
The taxon Genus was already in use.
He developed the taxa orders, classes and kingdoms.

7. George-Louis Leclerc Comte de Buffon (late 1700s)
Wrote the Histoire Naturelle, a 44 volume of natural history.
- noted the similarities between humans and apes (speculated a common ancestor)
One of the FIRST people to challenge the idea that life forms were UNCHANGING.

8. George-Louis Leclerc
Noted that species DO change over time. (Thought modern elephants were descendants of the Siberian mammoth)
Suggested the Earth was much older than 6,000 years old. (which was the common belief at the time)

9. Mary Anning
Fossil Hunter - discovered the first plesiosaur (aquatic reptile)
George Cuvier examined her work and acknowledged her discoveries.

10. Georges Cuvier Early 1800s - French naturalist.
- Developed the science of Palaeontology (study of fossils)
- Discovered that each layer of strata has a unique group of fossil species
- The deeper the strata the more different the species are from modern day

11. Species appeared and others disappeared over time.
This showed that species could become extinct!

12. CATASTROPHISM (Cuvier)
- Proposed that the Earth experienced many destructive natural events, such as floods and volcanoes led to mass extinctions!

13. Burgess Shale One of the world’s most celebrated fossil fields!
(Canadian Rockies, BC)
505 million years old
One of the earliest fossil beds containing imprints of soft parts!

14. Jean-Baptiste Lamarck
Early 1800s
- Studied fossils. Saw that some remained unchanged and others changed.
- Believed that living things evolved continually upward toward human perfection
- Organisms altered their behaviour in response to environmental change

15. INHERITANCE OF ACQUIRED CHARACTERISTICS
Behavioural changes modified traits
- lose it if you don’t use it
- continued use leads to increase in size
Modified traits were inherited.
* not quite right...

16. Charles Lyell Late 1800s - Scottish geologist
Did not agree with catastrophism!
UNIFORMITARIANISM
- geological processes were SLOW and operated at the same rates in the past as they do today
(Could subtle changes also occur in populations?)

17. THOMAS MALTHUS English economist:
“Essay on the principle of population” (1798)
- only a fraction of any population will survive and reproduce
- human population can increase linearly due to improvement in land use and improvements in agriculture
- reproductive potential is exponential
- famine war and disease will limit population growth (especially with the poor)