Origins of Evolutionary Thought Flashcards
“Nothing in biology makes sense, except in the light of evolution.”
- Theodosius Dobzhansky
All-powerful
omnipotent
All-knowing
omniscient
Doesn’t make mistakes
infallible and unchangeable
The biblical account of creation
Genesis 1
(land animals and human beings on Day 6)
The Great Chain of Being aka Scala Naturae
The prevailing view of the hierarchical organization of the natural world in medieval Europe
The prevailing thoughts of the time period…
- God is all powerful, all-knowing, infallible
- God is perfect and all His works are perfect
- Creation happened once
Fixity of Species concept
The number of different kinds of things on Earth are fixed
Their “ranking” does not change
Who was the first to challenge the Great Chain of Being?
Carl Linnaeus
Linnaeus’s Systema Naturae (1735)
System to organize the natural world
- Systema listed all “types” of life on Earth, grouped them in hierarchical organization, and described their qualities
- Introduced concept of taxonomy
- HOWEVER, he placed humans in a category with other animals! (Anthropomorpha)
Taxonomy
A branch of biology concerned with classification of life on Earth
What was Linnaeu’s motivation for creating Systema?
Religious; to honor God’s perfect creation and glimpse into God’s mind
- he believed that species were fixed…
Linnaeus was the Father of what?
Father of TAXONOMY
Systema established the taxonomic practices we still use today
- hierarchical system
- binomial nomenclature
- typology in biology (essentialism)
Hierarchical organization
Kingdom
Phylum
Class
Order
Family
Genus
Species
Buffon
Histoire Naturelle (1749) deviated from biblical account of creation
- Degeneration theory proposed minor improvements/degenerations (deviations from original life forms)
- argued for old Earth
Georges Cuvier
- Established extinction as a scientific fact
- Proposed the idea of Catastrophism
- But did NOT believe that one species could change into another
Jean-Baptiste Lamarck
Proposed that new species could originate by natural processes!
Lamarckian evolution
This is the FIRST fully-articulated theory of evolution!
- his theory was driven by two forces
What two forces was Lamarckian evolution driven by?
1.) Complexifying force
2.) Adaptive force
Adaptive force
Giraffes example
- original short-necked ancestor
- keeps stretching neck to reach leaves higher up on tree
- stretching until neck becomes progressively longer (concept of use vs. misuse)
- inheritance of acquired characteristics
Lamarck’s Inheritance of Acquired Characteristics
First mechanism proposed to explain fit between organism and environment
Complexifying force
Organisms get more complex over time
- idea of transmutation
Transmutation (Lamarck)
The idea that a species, as a whole, could change into another, more complex, species
