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Chapter

The Evolution of Biology Notes.docx


Department
Biology
Course Code
BIOL 3200
Professor
Jan Sapp

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The Evolution of Biology Notes 2014-09-13
Chapter 1: Evolution and Morphology
TWO WORLD VIEWS
- Charles Darwin convinced the scientific world of evolution in the 19th century
- Scientists say that today the universe is 10-20 billion years old, earth in 4.5 billion years old, life arose 3.5
billion years ago
- hominids appeared 4 million years ago
- Homo sapiens appeared 130 000 years ago
Intelligent Design:
- assumes that earth is only several thousand years old
- geologists have showed that the earth has experienced immense changes and fossil records show the
existence of many extinct forms that were here longer than thousands of years ago
Traditional natural theology: (emerged in 17th century)
- God formed all species as they appear today, species have no hereditary relationship between them
- Aristotle and Plato proposed the hierarchy of life, simple inanimate objects at the bottom, humans at the
very top
- “scala naturae” or “great chain of being”, understood in terms of different kinds of souls
- Evolutionary theory states that all species have genealogical relationship, and they resemble a branching
tree instead of a ladder or a pyramid
Teleology: organisms and their natural relations can only be explained by purpose or by design, or by the
final outcomes
- you basically explain a certain action by their results
Darwinian Evolutionary Theory
- there is no design in the natural world, no preconceived plan
- everything that has developed has been based on the conditions of the natural world

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- Theology placed humans above nature in the image of god, whereas Darwin’s theory places humans
within nature in the animal kingdom
REVOLUTION TO EVOLUTION: JEAN-BAPTISTE LAMARCK
- Lamarck’s view on evolution happened during the French Revolution
- Before the revolution, French society had a static hierarchical order
- uprising in 1789 changed this, and the revolution was over by 1804
- ending of the revolution had inspired the belief of freedom and equality, caused a liberal way of thinking
- During the revolution, Lamarck had a career shift as a prof and was to classify animals
- While classifying he started to explore questions and thought processes regarding evolution
- 3 convergent interests that led him to evolution:
1. Thoughts about what constituted the essence of life in simple organisms
2. His view of the “natural” way to arrange taxa
3. His interest in geological thinking (gradual changes over long periods of time)
LAMARCKIAN MYTHS
- He is remembered today for having originated a mechanism of evolutionary change that contradicted
Darwin’s
- His theory was based on inheritance of acquired characteristics
The characteristics you acquire in your lifetime maybe to passed on to subsequent generations like
property and wealth
characteristics acquired can be due to external changes in the environment e.g. darkening of skin bc of
sun exposure, disuse of a part, likes and dislikes acquired like an appreciation for music
BUT Lamarck did not necessarily state all of this
- There are 3 things wrong with attributing the belief that evolution is by inheritance of acquired
characteristics to Lamarck and saying it completely contrasts with Darwin’s beliefs:
1. Darwin’s gramps had actually used to same belief as the basis for his own theory of evolution
2. People forget that Darwin also believed in the inheritance of acquired characteristics

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3. Inheritance of acquired characteristics was only one aspect of Lamarck’s theory
- Lamarck thought environment could bring about heritable changes
e.g. giraffes have long necks to reach leaves on trees
- advocated that evolution was by desire on the part of animals
- people thought he proposed the ridiculous notion that evolution was done through will, specifically the will
of an animal
- Lamarck however was trying to say that it was through an animal’s habits, rather than their desires
SIMPLE TO COMPLEX
- While classifying organisms, Lamarck noticed there were certain species that branched off and formed
dead ends
- This could have been the result of the influence of particular environmental circumstances
Inheritance of acquired characteristics would account for different characters of organisms and
distinguish different species
- Inheritance of these characteristics by the use and disuse of parts would account for the many anomalies
or deviations from a linear and unbranched increase in complexity of classes
- Overall evolution results in increasing complexity of organisms, and Lamarck thought this was due to
some unknown force in nature called “the power of life
- So, Lamarck transformed the great chain of life into an escalator
organisms on the lower part of the escalator would eventually transformed to those higher up through the
process of evolution
- Naturalists argued that the structure of a part determined its function
- Lamarck argued the opposite, saying that new functions and habits are what led to changes in structure
- So, deviation from the great chain of being gave evidence of evolution by inheritance of characteristic
- Believed there was no extinction, species just evolved into something else
Why Lamarck failed to convince people of his theory:
1. Had a reputation of someone who would build speculative theories, his studies were very broad,
tried to set principles for ALL fields
2. Evidence for evolution was lacking in fossil record, no evidence of transitional forms of species
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