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Slajd 1


Nothing in biology makes sense, except in the light of evolution ... Darwin's Galapagos tortoise Harriet (ca 1830-2006) Thomas Robert Malthus (1766-1834) ... – PowerPoint PPT presentation

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Title: Slajd 1

Nothing in biology makes sense, except in the
light of evolution Theodosius Dobzhansky
Lecture outline
  • Introduction and historical notes
  • The discovery of the past
  • The reconstruction of phylogeny
  • Early times
  • History of life I From Proterozoic to Paleozoic
  • History of life II From Mesozoic to Cenozoic
  • Genetic basis of evolutionary change I
  • Genetic basis of evolutionary change II
  • Genetic basis of evolutionary change III
  • Genetic variation and fitness
  • Patterns of speciation and extinction
  • Selection, adaptation, and the rise of biological
  • Altruism and sociality
  • Human evolution I
  • Human evolution II

Pre Darwinian Views on Evolution The classical
Anaximander of Milet (610-546 BC) Anaximander
of Miletus considered that from warmed up water
and earth emerged either fish or entirely
fishlike animals. Inside these animals, men took
form and embryos were held prisoners until
puberty only then, after these animals burst
open, could men and women come out, now able to
feed themselves (Centorinus, 238 AC)
Empedocles(494?-434? BC) According to Aristotle
Empedocles proposed a struggle for life in the
animal kingdom
Platon (427-347 BC) developed the essentialism
in which the concept of eidos as an ideal form
that is imperfectly imitated by organisms
(Timaios). Variation of organisms is therefore
accidental imperfection.
The allegory of the cave 7 book of Politeia
Aristoteles (384-322 BC) developed the concept
of the scala naturae, the great chain of life.
Starting from inanimate objects and ending by
humans and spititual beings the scala naturae
gives every object and organism its permanent
place that is unchangeable.
There are three main levels Minerals Plants Anima
From Didacus Valadus
Rising empiricism
Vesalius (1514-1564) Founded modern anatomy from
dissections of corpses. He corrected the
classical work of Galen who dissected Barbary
apes instead of humans. He was the first to
describe organs in a mechanical way.
William Harvey (1578-1657) Rediscovered the
blood circularly system from dissections of
living animals. He also proposed that mammals
have eggs and he worked on embryology.
The mechanization of the world
René Descartes (1596-1650) Descartes was the
first to develop a theoretical framework for the
natural sciences. Descartes suggested that the
body works like a machine, that it has the
material properties of extension and motion, and
that it follows the laws of physics. He paved the
way to a mechanistic study of the living
world. On the other hand he believed that only
humans have a mind and animals lack souls.
Essentialism (eidos) Importance
of observations Mechanistic explanation
Carolus Linneus (1707-1778) His Systema naturae
(10. edition 1758) established the framework of
modern classification. While initially believing
that species were created and fixed, he changed
this view in the last edition of the Systema
naturae. Described plant sexuality Critised
Descartes for his mechanistic view of animals
Georges-Louis Leclerc, Comte de Buffon (1707
1788) In his Histoire Naturelle he questioned
the biblical view of earth history and proposed
that organism can undergo evolutionary change
although he lacked a precise theory of change.
Immanuel Kant (1724-1804) The Allgemeine
Naturgeschichte und Theorie des Himmels (1755) is
surely the first explicit evolutionary treatment
on the basis of Newtons mechanic. He also
speculated about the origin of life as a natural
Jean Baptiste Lamarck (1744-1829) As the
director of the Muséum National d'Histoire
Naturelle he developed the concept of
transmutation while studying molluscs.
Lamarck developed two laws to explain
evolution the law of use and disuse, and the law
of inheritance of acquired characteristics. Use
and disuse A frequent and continuous use of
organs gradually strengthens, develops and
enlarges them. This gives it a power proportional
to the length of time of use. The permanent
disuse of organs imperceptibly weakens and
deteriorates them, and progressively diminishes
its functional capacity, until it finally
disappears. Inheritance of acquired
characteristics All the acquisitions or losses,
through the influence of the environment and
through the influence of the predominant use or
permanent disuse of any organ are preserved
through reproduction.
Scale of organization
Scala naturae
Modern biology proved both laws to be wrong.
Spontaneous origin of simple life forms
The rise of Geology
Georges Cuvier (1769-1832) founded palaeontology
and comparative anatomy. His work on fossil
elephants (mammoths) convinced him that species
get extinct. He explained extinction from the
theory of catastrophism. His discovery of the
remains of Pterodactylus and Mosasaurus convinced
him that they were older than 6000 years. He was
sceptical about evolutionary theories.
Charles Lyell (1797-1875) expounded the principle
of uniformitarianism, holding that the same
geological processes operated in the past as in
the present The present is the key to the
past. He rejected the theory of catastrophism
and supported Darwins view on evolution.
Alfred Russel Wallace (1823-1913) Travelled
through the Amazon rainforest and the Malayan
archipelago. Developed in parallel with Darwin
the concept of gradually evolving species Every
species has come into existence coincident both
in space and time with a pre-existing closely
allied species. In 1958 he and Darwin presented
their views on evolution in a joint meeting of
the Linnean Society of London.
Charles Robert Darwin (1809-1882)
The voyage of the Beagle (1831-1836)
Comparative beak sizes of Darwin finches
Darwins Galapagos tortoise Harriet (ca 1830-2006)
Population growth and resources
Malthus thought that population growth is a
geometric process and food production a linear.
Today we know that population growth is an
exponential process. Food availability is more or
less constant.
Thomas Robert Malthus(1766-1834)
From this conclusion Darwin took his principle of
the struggle for existence
The number of progenies exceeds the capacity
(the amount of resources). Only some individuals
survive. Surviving probabilities differ due to
inherited individual variability.
Darwins theory of evolution
Changes of proportions are caused by differential
survival and reproduction of individuals due to
their natural variation (natural selection)
Differentialial survival and reproduction means
that individuals are differentially adapted to
their environment. The cumulation of different
adaptations causes the split of
lineages. Variation is hereditary
Evolution occurs by change in the proportion of
individuals that carry certain characters(populat
ion level)
Lineages that do not reach the top represent
extinct lineages Extinction results from
interspecific competition
Each node represents a common ancestor of the
lineages above
Characters of lineages change over time
Character change is a gradual process
All species in a focal evolutionary tree have a
common ancestor
The same evolutionary mechanisms work at all
taxonomic level
Basic questions of evolutionary research
Does evolution proceed directional (orthogenesis)
or is it a blind process?
Are lineages optimally adapted?
Can adaptations be acquired?(mechanistic basis)
How do proportions change?
Do different evolutionary processes operate at
different taxonomic levels?
What is variation?(material basis)
How common are speciation and extinction?
Are nodes always bifurcations?
How fast do characters change? (tempo of
Is evolution saltatorial? Are there hopeful
monsters? (mode of evolution)
Can we identify common ancestors? Are there
evolutionary brushes, networks, or rings ?
From University of California Museum of
General literature
Darwin Ch. 1859. The origin of species by means
of natural selection, or the preservation of
favored races in the struggle for life.
.htm The voyage of the Beagle. http//
/p.caimi/darwin.html Platon. Timaios.
9 Aristoteles. De Anima. http//
/jod/texts/aristotle.soul.html Immanuel Kant.
Allgemeine Naturgeschichte und Theorie des
Himmels. http//
Todays literature
Evolution. Selected papers and commentary.
http// A
concise history of evolutionary theories since
Darwin. http//
ogy/niklas.pdf History of Science.
htm Some biographies. http//