Evolution 3-The History of Evolution
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Immutable Definition
The idea that species cannot change
As far back as Aristotle (384-322 BCE), Europeans accepted what idea?
That Earth and all living things had been created in their present forms and were immutable - they could not change and had not changed.
Where did this idea that Europeans had accepted come from?
This idea came from religious beliefs, philosophical debate and thoughtful conjecture
In the 15th to 18th century, what took shape? What did it include? (5 points with 3 subpoints)
-In the 15th to 18th century, scientific methodology took shape. -It included: 1. Careful Observation 2. Experimentation 3. Deductive Reasoning
How did George-Louis Leclerc and Buffon view evolution? (4 points)
-(1707-1788), applied scientific methods to the detailed study of anatomy. -Became puzzled by anatomical features that seemed to serve no purpose. -Example: Why do pigs have extra toes that do not reach the ground? -Believed the species had been created in a more perfect form but had changed over time.
What did other scientists at the time, such as Carl Linneaeus and Erasmus Darwin, propose?
That life changed over time.
What did Erasmus Darwin (Charles Darwin’s grandfather) suggest?
That all life might have evolved from a single original source.
Why did Carl Linneaeus’ and Erasmus Darwin’s ideas remain speculative?
No plausible mechanisms for how this changed occurred therefore their ideas remained speculative.
What were Hutton’s views on evolution in terms of geology? (3 points)
• Hutton’s (1795) theory of gradualism proposed that major changes are the result of slow small changes. • It also proposed that the earth at one time was one large supercontinent known as Gondwana that then evolved into Pangea. • Furthermore, it stated that eventually, through plate tectonics, it is what it is today, which includes seven continents.
What were Lyell’s views on evolution in terms of geology? (2 points with 2 subpoints)
• Lyell (1830), believed that geological changes throughout time have been subjected to the same forces. -His conclusions were: 1. If geological changes are slow, earth is older than 6,000 years old. 2. The slow changes can build and result in profound environmental changes over time
What has changed over time and in turn has changed what?
Life has changed over time and in turn has changed the Earth.
What were Chevalier and Jean-Baptiste Lamarck’s views on evolution? (5 points with 4 subpoints)
-(1744-1829) -Organisms adapted to their environments 1. Through acquired traits 2. Change in their life time -Use and Disuse 1. Organisms lost parts because they did not use them — like the missing eyes & digestive system of the tapeworm -Perfection with Use and Need 1. The constant use of an organ leads that organ to increase in size, for example: the muscles of a blacksmith and the large ears of a night-flying bat -Transmit acquired characteristics to the next generation.
What was Lamarck’s Giraffe example? (2 points)
-Lamarck believed that if an adult giraffe stretched its neck during its lifetime, then its offspring would be born with slight longer necks -This was a flawed theory, because physical changes do not result in changes in genes, and therefore, are not passed on.
What were Malthus’ views on evolution? (4 points)
-(1978)-Published that populations increase faster than environment can handle. -Capacity to over-reproduce is seen in all species. -There will be a struggle for survival between the members of the population. -Reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone.
What happened when Charles Darwin came along? (2 points with 3 subpoints)
• Invited to travel around the world. • Voyage of the HMS Beagle 1. 1831-1836 (22 years old!) 2. Makes many observations of nature 3. Main mission of the Beagle was to chart South American coastline
What happened on Charles Darwin’s Voyage on the HMS Beagle?
• Stopped in Galapagos Islands, which is 500 miles off the coast of Ecuador
What is significant about the Galapagos Islands? (2 points)
-Recent volcanic origin. -Most of animal species on the Galápagos live nowhere else in world, but they resemble species living on South American mainland.
What was the significance of Darwin’s Finches? (2 points)
-Darwin was amazed to find out that on the Galapagos Islands, all 14 species of birds were finches. -But, there were only one species of finch on the mainland.
What is Rapid Speciation?
When new species fill niches, because they inherited successful adaptations.
Why was it not just finches that differed? (2 points)
-Many of the Galapagos Islands also show distinct local variations in tortoise morphology. -Both the finch and tortoise morphology differing were perhaps the first steps in the splitting of one species into several.
What are the points of Darwin’s Theory? (5 points)
• Organisms differ; variation is inherited • Organisms produce more offspring than survive • Organisms compete for resources • Organisms with advantages survive to pass those advantages to their children • Species alive today are descended with modifications from common ancestors