Scientific ContributionsScientific ContributionsScientific ContributionsScientific ContributionsTo a Theory of Evolution

8.1

To a Theory of Evolution8.1

Scientific theoryScientific theoryScientific theoryScientific theory

Ask QuestionsAsk Questions

Scientific HypothesisScientific Hypothesispossible explanation for observationspossible explanation for observations

make observationsmake observations

Hypotheses are testedHypotheses are testedexperiments, models, observations...experiments, models, observations...

Scientific theoryScientific theory

consistently lead to successful predictions and explanationsconsistently lead to successful predictions and explanations

Where did we Where did we come froM?come froM?

Where did we Where did we come froM?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

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

But, many scientists came before

Charles Darwin.

He put all the pieces together and had the courage to

publish it...

But, many scientists came before

Charles Darwin.

He put all the pieces together and had the courage to

publish it...

When we think of evolution - we think of When we think of evolution - we think of Darwin.Darwin.

When we think of evolution - we think of When we think of evolution - we think of Darwin.Darwin.

John RayJohn RayJohn RayJohn RayLate 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

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

Carl LinnaeusCarl LinnaeusCarl LinnaeusCarl LinnaeusKing of Classification!

(Remember the diversity of life unit?)

The taxon Genus was already in use.

He developed the taxa orders, classes and kingdoms.

King of Classification!

(Remember the diversity of life unit?)

The taxon Genus was already in use.

He developed the taxa orders, classes and kingdoms.

George-Louis George-Louis LeclercLeclercGeorge-Louis George-Louis LeclercLeclerc

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.

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.

Comte de Buffon (late 1700s)Comte de Buffon (late 1700s)

George-Louis LeclercGeorge-Louis LeclercGeorge-Louis LeclercGeorge-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)

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)

Mary AnningMary AnningMary AnningMary Anning1799 - 1847

Fossil Hunter - discovered the first plesiosaur (aquatic reptile)

George Cuvier examined her work and acknowledged her discoveries.

1799 - 1847

Fossil Hunter - discovered the first plesiosaur (aquatic reptile)

George Cuvier examined her work and acknowledged her discoveries.

Georges Georges CuvierCuvier

Georges Georges CuvierCuvier

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

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

Species appeared and others disappeared over time.

This showed that species could become extinct!

Species appeared and others disappeared over time.

This showed that species could become extinct!

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

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

Burgess Burgess ShaleShale

Burgess Burgess ShaleShale

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!

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!

Jean-Baptiste Jean-Baptiste LamarckLamarck

Jean-Baptiste Jean-Baptiste LamarckLamarck

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

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

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...

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...

Charles Charles LyellLyell

Charles Charles LyellLyell

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?)

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?)

THOMAS THOMAS MALTHUSMALTHUSTHOMAS THOMAS MALTHUSMALTHUS

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)

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)