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BIOL 3200 Study Guide - Midterm Guide: Zoology, Transitional Fossil, Natural Selection

Course Code
BIOL 3200
Jan Sapp
Study Guide

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Evolutionary Theory: the natural world is steadily changing; organisms have diverged from
common ancestors and have been transformed over geological time
Two World Views
Archbishop James Usher (17thc): calculated the origin of creation to year 4004 BC
Georges Louis Leclerc, Comte de Buffon: French naturalist who estimated that the
earth was about 75,000 years old, and that plants/animals around ~37,000 years ago
Scientists Today
o Universe is 10-20 billion years old, Earth is ~4.5 billion years old
o Life on Earth arose ~3.5 billion years ago; hominids resembling our species arose
~4 millions years ago; Homo sapiens arose ~130,000 years ago
Traditional natural theology held the world to be static god had formed all
species just as they appear today, with no genealogical relationships between them
Ancient Greek philosophers: there were great cataclysms (e.g. Biblical flood), but
Noah had saved all the species that live today
Aristotelian and Platonic view: life-forms were ordered in single-file, from the most
simple inanimate objects, to plants, to animals fixed plan of creation
o Known as Scala Naturae “Great Chain of Being”
Its increasing perfection was understood in terms of different kinds of
‘soul’ more reason, and a greater advance toward god
In contrast to scala naturae, evolutionary theory holds that all life is related and
genealogical relations don’t resemble a chain/ladder, but a tree
Teleology: view that organisms and their natural relations can only be explained by
purpose and intelligent design
o Judeo-Christian theology puts humans above nature created in image of god
Darwinian Evolutionary Theory: there’s no design/preconceived plan in the natural
world, and organisms evolve in a makeshift way contingent on ecological conditions
o Nothing is necessary or purposeful different conditions, different world
o Put humans in nature as members of the animal kingdom
Jean-Baptiste Lamarck: most prominent pre-Darwin evolutionist
o Coined the term ‘biology’ for the study of the manifestation of life, and the
conditions in which it occurs
Revolution to Evolution
Before the Revolution, French society was a static hierarchy from birth
Structure disturbed by uprising of peasants, artisans and the middle class until
Napoleon Bonaparte seized control and became emperor of France end of rev.
o After the revolution, people started believing in equality, freedom to emigrate
Word ‘evolution’ first used by Robert Grant
During Reign of Terror, the Jardin du Roi (where Lamarck was a botanist), was
reorganized into a museum, where he was given a job as a zoologist
o He worked in classification of invertebrates, and coined the term ‘invertebrate
Led him to explore questions about causes of life processes/evolution

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3 convergent interests that led Lamarck to evolution:
o Thinking on what constituted the essence of life in simplest organisms (caloric
heat and electricity)
o His view of the ‘natural’ way to arrange taxa
o His geological thinking (i.e. gradual change over long periods of time)
Believed the earth is incalculably old unique view for the time period
Lamarckian Myths
Myths about Lamarck
o ‘Romantic genius’ ignored by his contemporaries but later rediscovered
o Someone who failed to tackle adaptation/origin of species before Darwin
o Lamarck based his evolution theory on inheritance of acquired characteristics
o Darwin opposed the inheritance acquired characteristics he believed in it!
He is remembered by biologists as having originated a mechanism of evolution that
differed from Darwin’s based on inheritance of acquired characteristics
o Found to not occur, but it’s wrong to attribute this view to Lamarck because:
He didn’t think of it can be traced back to Hippocratic writers
Before him, Erasmus Darwin used it as the basis for his theory
He is ridiculed for the idea, but Darwin also held the idea of inheritance
of acquired characteristics (many evolutionists of the time did)
Inheritance of acquired characteristics is only one part of his theory
He thought the environment brought about heritable changes in
many different ways
Ridicule of him was often said to be due to the unclear ways he expressed his ideas
o Often seemed that he believed evolution was based on the desire of the animal,
but what he actually meant was that the animal’s habits impacted evolution
Simple to Complex
Lamarck arranged life-forms by ordering the great classes of life in a linear, graded
series moving toward “perfection i.e. simple to complex (like scala naturae)
o Lamarck’s scientific style was speculation, focusing on big systems
He said that branching/deviation from the linear order were due to the influence of
certain environmental circumstances
o Inheritance of acquired characteristics would account for the characters of
organisms that distinguished genera and species, as well as their instincts/habits
o General trend of evolution towards increasing complexity was due to an
unknown inner force in nature which he called the “power of life
Naturalists who believed in the fixity of a species believed that the structure of an
animal is perfectly fit for their functions, structure of a part determines its function
o Lamarck believed that new functions/habits brought about by needs led to
changed structures and irregularities in the line from simple to complex
George Louis Buffon: studied living organisms and their characteristics in life; also
adopted a theory of evolution according to which a few original types of animals
developed, and evolved into the animals we see today via hybridization and
environmental influences (Linneaus had similar view did binary classification)
Lamarck’s theory was not well-supported by the fossil record often whole species
seemed to appear suddenly, which goes against Lamarck’s gradual evolution theory

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o The progressive, unified order of things he proposed was debunked by this
Disconnecting the Unity of Life
Georges Cuvier: a professor of natural history at College de France, who also
worked in comparative anatomy at the museum with Lamarck main antagonist
o Famous for being able to identify many characteristics about an animal just by
looking at its tooth
Cuvier built a rival system based on a new approach to comparative anatomy
Cuvier was a fixist view that species alive today are identical to ancient ones
o Lamarck denied species extinction; Cuvier believed in several mass extinctions
On top of Lamarck’s reputation, Cuvier had a reputation of solid methodology and
observation, and was very similar to and well-regarded by Napoleon
Cuvier claimed there are 4 distinct, unrelated divisions of animals: vertebrates,
mollusks, articulates (annelids/arthropods), and radiates (starfish, coral, jellyfish)
o Divisions determined by the animals’ internal anatomy, which Cuvier believed
had been designed by the Creator to suit the animals’ certain functional needs
Cuvier believed that the history of life on early was marked by major catastrophes
and mass extinctions last one was the biblical flood
o Implied breaks in geological time and in life on earth he saw no connection
between early animals and animals today
o When catastrophe wiped out animals in a certain area, animals from other
species would migrate in and invade that area next disaster fossilizes them
there animals don’t evolve, preexisting species from other areas move in
Accounts for changes in fossil record in different regions and strata
Flaw: if there was many catastrophes, species number would have declined, not
increased some of Cuvier followers developed a solution:
o There was not just one divine creation there’s one after each catastrophe
Lamarck eventually realized his linear model didn’t reflect nature
Some scholars have claimed that Cuvier’s ideas were progressive, and that
Lamarck’s ideas were looking to the past, basically copying the Great Chain of Being
The Cuvier-Geoffroy Debate
Etienne Geoffroy: professor of zoology who was a famous antagonist of Cuvier
o Was a follower of Lamarck
Evolution was position in opposition to the privileges of nobility and the church, and
against the conservative and new professional social control of science in France
Their debate centered on two opposing approaches to comparative anatomy
o Cuvier: functionalist, thought that every part of an animal was designed by a
creator to contribute to the animal’s functional integrity
Function dictates structure
o Geoffroy: believed that structure dictates function
Developed transcendental/philosophical anatomy, which centered on
the concept that all animals had a structural plan to suit their functions
Structural plan precedes any modifications/adaptations (e.g. all
vertebrates have the same basic structural plan, and are all
modifications of the same being, called “the vertebrate animal”)
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