BIOL*2400 Midterm Notes
Biological evolution: any change in the inherited traits of a population that occurs from one
generation to the next
History of Evolutionary Thought
Special creation
o Each organism originated independently
o Since the time of creation, each organism has remained the same
o All organisms were created recently
Early Greeks
o Explained nature through material principles (basis of scientific thought)
o Science rejects supernatural explanations (Greek mythology - Plato)
o Creatures come together in random strange ways
Carl Linnaeus (1707 – 1778)
o Established conventions for naming organisms and created binomial species
o Species Plantarum in 1753
o Systema Naturae in 1758
o Organized things into a hierarchy called taxonomy: science of describing,
naming, and classifying species of living or fossil organisms
o Divided world into 3 kingdoms and used 5 ranks
1. Kingdom, Phylum, Class, Order, Family, Genus, Species
Jean-Baptiste Lamarck (1744 – 1829)
o Believed living things evolved in a continuous upward direction
o Viewed species as populations of individuals showing variation
o First law: simplest forms of life continue to arise from inanimate matter and
evolve to create higher forms
1. Life driven from simplicity to complexity
o Second Law: all such changes were heritable, continuous, and gradual change of
all organisms as they became adapted to their environments
1. Species change through time by inheritance of acquired characters
2. New environments create new needs, physiology (organs), etc
3. E.g. giraffes’ necks evolved to be longer due to stretching overtime so
they would produce offspring with slightly longer necks
, Charles Darwin (1809 – 1882)
o British naturalist who proposed the theory of natural selection: the process
through living organisms’ phenotypes adapt and change due to environment and
tend to survive and produce more offspring, thus trait will become more
common in species population over generations
o His conclusion defined evolution in species as descent with modification:
The idea that species change overtime and give rise to new species and
share a common ancestor
Individuals of species will be born with some slight variation due to their
environment and they will have a better chance of surviving
The variety formed will either coexist with or more commonly will
exterminate its ancestral form
Darwins Voyage on the Beagle (1831 – 1836)
Darwin set sail on the ship HMS Beagle in 1831 and mainly travelled around south
america in the Galapagos Islands
He studied Principles of Geology by Lyell
o Geologic change as the steady accumulation of minute changes over big, long
spans of time not gigantic catastrophes
o Known as Uniformitarianism: observable present natural processes responsible
for events in the past
He studied Essay on the Principles of Population by Malthus
o Human populations increase geometrically, food sources increase arithmetically,
and population outstrips its resources
Central theme was population growth would always overpower food
supply growth, creating states of hunger, disease, and struggle
Darwin started a notebook in 1837 on variation which included observations….
o Lots of diversity of similar forms
He collected birds he thought were wrens, blackbirds, and finches, but
turns out they were all just kinds of finches
o Contradictory to creationism, nearby islands had different species
o Species fit well with their environments
o Fossils were clearly associated with extinct things but dramatically different
o Law of Succession: fossils and living organisms from one area were like each
other but different from those in other areas
o Could be similarities due to common ancestry (homologies)
Humans, seals, bats, etc looked different but closer examination
showed similar bone arrangements
o Darwin didn’t publish notebook knowing everyone believed in creationism, until
Wallace wrote a letter to him with a similar concept
Giraffes didn’t acquire longer necks by desiring to reach the shrubs so
the neck stretches overtime, but because any giraffes in the population
with the longer neck phenotype would secure fresh food compared to
their shorter neck companions and therefore lived longer”
Biological evolution: any change in the inherited traits of a population that occurs from one
generation to the next
History of Evolutionary Thought
Special creation
o Each organism originated independently
o Since the time of creation, each organism has remained the same
o All organisms were created recently
Early Greeks
o Explained nature through material principles (basis of scientific thought)
o Science rejects supernatural explanations (Greek mythology - Plato)
o Creatures come together in random strange ways
Carl Linnaeus (1707 – 1778)
o Established conventions for naming organisms and created binomial species
o Species Plantarum in 1753
o Systema Naturae in 1758
o Organized things into a hierarchy called taxonomy: science of describing,
naming, and classifying species of living or fossil organisms
o Divided world into 3 kingdoms and used 5 ranks
1. Kingdom, Phylum, Class, Order, Family, Genus, Species
Jean-Baptiste Lamarck (1744 – 1829)
o Believed living things evolved in a continuous upward direction
o Viewed species as populations of individuals showing variation
o First law: simplest forms of life continue to arise from inanimate matter and
evolve to create higher forms
1. Life driven from simplicity to complexity
o Second Law: all such changes were heritable, continuous, and gradual change of
all organisms as they became adapted to their environments
1. Species change through time by inheritance of acquired characters
2. New environments create new needs, physiology (organs), etc
3. E.g. giraffes’ necks evolved to be longer due to stretching overtime so
they would produce offspring with slightly longer necks
, Charles Darwin (1809 – 1882)
o British naturalist who proposed the theory of natural selection: the process
through living organisms’ phenotypes adapt and change due to environment and
tend to survive and produce more offspring, thus trait will become more
common in species population over generations
o His conclusion defined evolution in species as descent with modification:
The idea that species change overtime and give rise to new species and
share a common ancestor
Individuals of species will be born with some slight variation due to their
environment and they will have a better chance of surviving
The variety formed will either coexist with or more commonly will
exterminate its ancestral form
Darwins Voyage on the Beagle (1831 – 1836)
Darwin set sail on the ship HMS Beagle in 1831 and mainly travelled around south
america in the Galapagos Islands
He studied Principles of Geology by Lyell
o Geologic change as the steady accumulation of minute changes over big, long
spans of time not gigantic catastrophes
o Known as Uniformitarianism: observable present natural processes responsible
for events in the past
He studied Essay on the Principles of Population by Malthus
o Human populations increase geometrically, food sources increase arithmetically,
and population outstrips its resources
Central theme was population growth would always overpower food
supply growth, creating states of hunger, disease, and struggle
Darwin started a notebook in 1837 on variation which included observations….
o Lots of diversity of similar forms
He collected birds he thought were wrens, blackbirds, and finches, but
turns out they were all just kinds of finches
o Contradictory to creationism, nearby islands had different species
o Species fit well with their environments
o Fossils were clearly associated with extinct things but dramatically different
o Law of Succession: fossils and living organisms from one area were like each
other but different from those in other areas
o Could be similarities due to common ancestry (homologies)
Humans, seals, bats, etc looked different but closer examination
showed similar bone arrangements
o Darwin didn’t publish notebook knowing everyone believed in creationism, until
Wallace wrote a letter to him with a similar concept
Giraffes didn’t acquire longer necks by desiring to reach the shrubs so
the neck stretches overtime, but because any giraffes in the population
with the longer neck phenotype would secure fresh food compared to
their shorter neck companions and therefore lived longer”
