Unit 1: Evolution - The Evolution of an Idea Flashcards
What is “immutable”?
The idea that species cannot change
What happened as far back as Aristotle (384-322 BCE)?
Europeans accepted the 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 come from?
From religious beliefs, philosophical debate and thoughtful conjecture
In the 15th to 18th century scientific methodology took shape. What did this entail?
- Careful Observation
- Experimentation
- Deductive reasoning
What did George-Louis Leclerc & Buffon do?
(1707-1788) Applied scientific methods to the detailed study of anatomy
What did George-Louis Leclerc & Buffon become puzzled by?
Anatomical features that seemed to serve no purpose (i.e. Why do pigs have extra toes that do not reach the ground?)
What did George-Louis Leclerc & Buffon believe?
The species had been created in a more perfect form but had changed over time
What did Carl Linneaeus & Erasmus Darwin propose?
That life changed over time.
What did Erasmus (Darwin’s Grandfather) suggest?
That all life might have evolved from a single original source
What did not occur?
No plausible mechanisms for how this changed occurred therefore their ideas remained speculative
What was Hutton’s theory of gradualism?
That major changes are the result of slow small changes
What was part of this theory of gradualism?
The earth at one time was one large supercontinent known as Gondwana then evolved into Pangea.
Theory of Gradualism-through what how is the earth today?
Eventually through plate tectonic it is what it is today. Seven continents.
What were Lyell’s beliefs?
Geological changes throughout time have been subjected to the same forces
What were Lyell’s conclusions?
If geological changes are slow, earth is older than 6,000 years old
The slow changes can build and result in profound environmental changes over time
What did Chevalier & Jean-Baptiste Lamarck believe?
Organisms adapted to their environments
- through acquired traits
- change in their life time
What was Chevalier & Jean-Baptiste Lamarck’s theory include with regards to use and disuse?
Organisms lost parts because they did not use them — like the missing eyes & digestive system of the tapeworm
What was Chevalier & Jean-Baptiste Lamarck’s theory include with regards to Perfection with use and need?
The constant use of an organ leads that organ to increase in size, for example:
the muscles of a blacksmith
the large ears of a night-flying bat
What else did Chevalier & Jean-Baptiste Lamarck’s believe?
Transmit acquired characteristics to next generation
What did Lamarck believe with regards to giraffes?
That if an adult giraffe stretched its neck during its lifetime, then its offspring would be born with slight longer necks
What kind of theory is Lamarck’s giraffe theory?
A Flawed theory!!!
Why is Lamarck’s giraffe theory flawed?
Physical changes do not result in changes in genes, therefore are not passed on
What did Malthus publish?
That populations increase faster than environment can handle
What is seen in all species according to Malthus?
Capacity to over-reproduce is seen in all species
What will there be a struggle for according to Malthus?
Between the members of the population
What did Malthus reason?
That if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone
What was Charles Darwin invited to do?
Travel around the world
What did he voyage on?
The HMS Beagle
What did he make?
Many observations of nature
What was the main mission of the Beagle?
To chart South American coastline
Where did the HMS Beagle stop?
In Galapagos Islands, 500 miles off coast of Ecuador
Describe Galapagos
- 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 Darwin amazed to find out?
All 14 species of birds on the island were finches, but there was only one species of finch on the mainland.
What is Rapid Speciation?
New species filling niches, because they inherited successful adaptations.
Why was it not only finches?
Many islands also show distinct local variations in tortoise morphology…
What is the first point of Darwin’s theory?
Organisms differ; variation is inherited
What is the second point of Darwin’s theory?
Organisms produce more offspring than survive
What is the third point of Darwin’s theory?
Organisms compete for resources
What is the fourth point of Darwin’s theory?
Organisms with advantages survive to pass those advantages to their children
What is the fifth point of Darwin’s theory?
Species alive today are descended with modifications from common ancestors
