Download Ch. I Introduction

Ch. I Introduction
• Inorganic evolution--- E. of celestial sphere, earth, sun, . . .
• Chemical E. --- origin of life
• Organic evolution --- E. of organisms
Anagenesis (;Phyletic E.) : E within a species
; Subspecific E. ; Microevolution
Cladogenesis(; speciation) : E across species
≤Transspecific E. ≤Macroevolution
Definition of evolution
-(Wikipedia)
: the change in the inherited characteristics of biological
populations over successive generations
- Dovzhansky (1973)
: Organic evolution is a series of partial or complete and irreversible
transformations of the genetic composition of populations, based
principally on altered interactions with their environment. It consists
chiefly of adaptive radiations into new environments, adjustment to
environmental changes that take place in a particular habitat, and
the origin of new ways for exploiting existing habitats. These
adaptive changes occasionally give rice to greater complexity of
developmental pattern, of physiological reactions, and of
interactions between populations and their environment.
Microevolution
(Evolution within species)
Macroevolution
단자엽식물
Monocots
(Evolution across species)
동백아강
Angiosperms
백합아강
쑥부장이아강
장미아강
닭의장풀아강
석죽아강
택사아강
생강아강
조록나무아강
목련아강
종려아강
A short history of evolutionary biology
1.
2.
3.
4.
5.
before Darwin
Darwin's theory (1859)
The eclipse of Darwin (1880s-1920s)
The modern synthesis (1920s-1950s)
Developments within the modern synthesis (1960s-present)
1. before Darwin
(1) Classical tradition
•
•
Aristotle (384-322 BC) : The theory of Forms
- the theory of types or of essentialism
- All organisms have their own ‘eidos’(heavenly form).
- fixed “Chain of being” (생물 존재의 서열)
Carl Linnaeus (1707-1778): botanist in Sweden,
Leader of Classical tradition
- “Systema Naturae” (system of nature or natural system)
- set up a modern classification system
: kingdoms, classes, orders, genera, species
(2) Non-Darwinian evolutionists
• Jean Baptiste Larmark (1744-1829)
: 1809. “ Philosophie Zoologique ”
- use and non-use theory,
- transmission of acquired characters
• Georges Cuvier (1769-1832)
- Catastrophism: Earth has been affected in the past by sudden,
short-lived, violent events, possibly worldwide in scope. Many of the
geological features of the earth and the history of life could be
explained by catastrophic events that had caused the extinction of many
species of animals.
연구)
- Cuvier’s stratigraphy
(지질학적 사건의 순서를 이해하는 계층화된 바위
• Charles Lyell (1797-1875)
: 1830. Principles of Geology
- Uniformitarianism (균일론)
(the assumption that the same natural laws and processes that operate in
the universe now, have always operated in the universe in the past and
apply everywhere in the universe. It has included the gradualistic concept
that "the present is the key to the past" and is functioning at the same
rates. Uniformitarianism has been a key principle of geology and virtually
all fields of science.)
2. Darwin's theory
• Charles Robert Darwin (1809-1882)
1859. On the Origin of Species –
by Means of Natural Selection,
or the Preservation of Favoured Races in the Struggle for Life
Voyage of the Beagle
- All species, living or extinct, have descended w/o interruption from one or
a few original forms of life. Living things have not been created. Closely similar
species have diverged from a relatively recent ancestor by the accumulation
of slight differences.
- Much of natural variations are inherited. Species is being changed through
the accumulation of heritable variations.
- If variations useful to any organic being ever occur, assuredly individuals
thus characterized will have the best chance of being preserved in the
struggle for life. ; the survival of the fittest  Theory of natural selection
Ernst Mayr’s summary on Darwin’s theory of evolution
(1) Evolution as such : Characteristics of lineages organisms change over time.
with lots of evidences.
(2) Common descent: Species had diverged from common ancestors.
(3) Gradualness: Differences between organisms evolve by innumerable small
steps through intermediate forms.
(4) Population speciation: Evolution occurs by changes in the proportions of
individuals within a population that differ in one or more heritable
characteristics
(5) Natural selection: What causes the proportions of variant individuals within
a species to change is N.S. through ‘the struggle for life’ and adaptation.
3. The eclipse of Darwin (1880s-1920s)
with the developments in Genetics
• G. Mendel(1822-1884)’s genetic law
1865. “Experiments on plant hybridization”
• 1990. Rediscovery of Mendelism
• T. Morgan(1866-1945)’s chromosome theory
Controversy between Mendelian geneticsts and naturalists
Mendelian geneticsts
Naturalists
Typological thinking: Natural
populations are uniformly ‘wild type’.
Population thinking: : Natural
populations are extremely variable.
Variation is discrete; Changes are
discrete and sudden; Inheritance is
particulate.
Variation is continuous; Changes are
small and gradual; Inheritance is by
blending.
Variation arises at random.
Variation is adaptive, showing influence
of environment. This influence is often
by direct induction and inheritance od
acquired characteristics.
Geographic variation is a phenotypic
response only, and is thus unimportant.
Geographic variation is genotypic and
important.
Species are real, discrete.
Species are variable (especially
geographically); Transitional forms can
sometimes be found b/t named species.
New species arise suddenly by saltation. New species arise gradually.
(=mutation)
4. The modern synthesis (1920s-1950s)
1926. S.S.Chetverikov. "On certain aspects of the evolutionary process from
the standpoint of genetics" Zhurnal Exp.Biol.1:3-54
1930. R.A.Fisher. "The genetical theory of natural selection"
--- 1st attempt to interpret Darwin’s observations with Mendelian genetics
1931. S.Wright. "Evolution in Mendelian population
1932. J.B.S.Haldane. "The causes of evolution“ --- population genetics
1937, 1941, 1951 T.Dobzhansky. "Genetics and the origin of species“
1942. E.Mayr. "Systematics and the origin of species"
1940, 1942. J.Huxley. “New systematics"(1940), "Modern synthesis"(1942)
: ‘neo-Darwinian’ 또는 ‘modern’ synthesis
1944. G.G.Simpson. "Tempo and mode in evolution"
1950. G.L.Stebbins. "Variation and evolution in plants"
The major features of evolution (Stebbins, 1977)
Modern synthetic theory
Darwin’s theory
1.
2.
3.
Variation
Natural selection
(Use and disuse)
1.
2.
3.
4.
5.
Single gene mutations
Genetic recombination
Changes in chromosome
structure or chromosome
number
Natural selection
Reproductive isolation
- Mutations and recombination produce heritable variation among individuals
upon which natural selection acts.
- Many times, different populations of the same species will inhabit different
environments and as a result be subjected to different selective pressures.
- In the source of adapting to different environments, populations will gradually
change and become genetically divergent.
- As the degree of genetic divergence increases, reproductive isolation between
divergent populations will gradually develop until, eventually, genetically
divergent populations become reproductively isolated from each other.
- At this point a new species has been formed. Speciation results from adaptive
changes in different environments accompanied by reproductive isolation.
- Moreover, the same process of gradual divergence that generate new species,
carried out over sufficiently long periods of time, generates the differences we
observe between the higher taxonomic categories.
5. Developments within the modern synthesis (1960s-present)
Contemporary evolutionary studies (18:28, Futuyama)
(1) (Genetic) mechanism of evolution
- How do the mechanism of mutation and recombination limit the range of
variations that are available to natural selection ?
- Why is there as much genetic variability within species as there is?
- Do levels of variability set limits on the rate or direction of a species'
evolution?
- How intense and consistent is natural selection?
- What ecological factors and genetic changes cause populations to
become new species?
- Are all evolutionary changes are gradual?
(2) The evolution of adaptations
- How can we explain differences among species in such features as
longevity, reproductive rate, body size, migratory habit, sex ratio, sexual &
asexual reproduction?
- Why are some species hermaphroditic while others have distinct sexes?
Why are some species, such as insects that feed on only a single kind of
plant, extraordinarily specialized, and others not?
- Why does a species have ecological and geographic limits to its range,
instead of adapting to the terrain beyond?
- What limits the extent of further adaptation?
(3) Molecular insight into evolution
- Why does eukaryotic genome carry so much 'useless' DNA?
- How much evolution at the DNA level is caused by natural selection, and
how much is nonadaptive?
- What is the evolutionary importance of changes in gene regulation?
- What kind of genes evolve slowly vs. rapidly?
(4) Patterns in evolutionary history
- Why do species become extinct rather than adapting to environmental
changes?
- Why have some phyletic lineages produced more species than others?
- Can we explain the changes in numbers of species that have occurred
over the history of life?
- Why is evolution, as viewed in the fossil record, usually so slow?
* endosymbiosis
: When one
organism
actually lives
inside the other
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Evolutionary
developmental
biol.
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http://evolution.berkeley.edu/evosite/history/historyslice1.shtml
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(Source: http://www.ucmp.berkeley.edu/history/evotmline.html)