I AM HAFIZ MUHAMMAD WASEEM from mailsi vehari BSc from science college Multan MSC university of education Lahore i love Pakistan and my teachers

1. Evolution and principles of systematics
ZOOL-3116
History of Evolutionary Thought
Dr. Muhammad Mudassar Shahzad
Dr. Muhammad Mudassar Shahzad
(DSNT Zoology)

3. AL-BIRUNI 973 - 1048
• Gradual changes
• But change is dangerous…

4. Erasmus Darwin
Darwins Grandfather Erasmus
Wrote about evolution – but in poetry – in poems the dangerous ideas
were less obvious
Coat of arms ‘ from shells comes everything’ a statement of his belief in
Evolution
Was made to remove it from his coach by the Bishop of Lichfield – he
understood the danger of these ideas even though they were in Latin

5. What was the view of the world and nature before Darwin?
1. Static Universe
The universe didn’t change through time
Problem - Fossil Evidence

6. What was the view of the world and nature before Darwin?
1. Static Universe
2. Earth Centred Universe
Galileo - showed that this was wrong

7. What was the view of the world and nature before Darwin?
1. Static Universe
2. Earth Centred Universe
3. Great Chain of Being
Problem - how do you incorporate new species?

8. What was the view of the world and nature before Darwin?
1. Static Universe
2. Earth Centred Universe
3. Great Chain of Being
4. Argument from Design
Each species was designed for a specific purpose
Problem:

9. How did this ‘traditional’ view (or Natural Theology)
apply to Biology?
1. Argument from Design
The design of all organisms showed that
there was an intelligent and benevolent Creator
BUT….
How do disease
organisms fit into
this scheme ?
Ebola

10. How did this ‘traditional’ view (or Natural Theology)
apply to Biology?
1. Argument from Design
2. Relationship between Species
(Great Chain of Being)
BUT ..
vulnerable to
extinction

11. How did this ‘traditional’ view (or Natural Theology)
apply to Biology?
1. Argument from Design
2. Relationship between Species
3. Fixed Species and Relationships
How do you incorporate new species?

12. Pre-Darwinian Ideas of Organic Change
1. Georges Louis Leclerc, Comte de Buffon (1707-1788)
Species - a distinct group maintained by
reproduction
Ancestor
Different
species
Time
Local
Conditions

13. Pre-Darwinian Ideas of Organic Change
1. Georges Louis Leclerc, Comte de Buffon (1707-1788)
2. Jean-Baptiste Lamarck (1744-1829)
Lamarck’s ideas:
1. Spontaneous generation

14. Pre-Darwinian Ideas of Organic Change
1. Georges Louis Leclerc, Comte de Buffon (1707-1788)
2. Jean-Baptiste Lamarck (1744-1829)
Lamarck’s ideas:
1. Spontaneous generation
2. Ascent up the scale of nature
Time
Complexity of the
organism
Different species

15. Pre-Darwinian Ideas of Organic Change
1. Georges Louis Leclerc, Comte de Buffon (1707-1788)
2. Jean-Baptiste Lamarck (1744-1829)
Lamarck’s ideas:
1. Spontaneous generation
2. Ascent up the scale of nature
3. Acquired characteristics

16. Jean Baptiste LAMARCK
1744 – 1829
• Lamarck rejected fixity
• He proposed a theory of evolution which is attractive but it
was eventually rejected because of the way inheritance works
Lamarck

17. Adaptation and specialisation
• Lamarck noticed that organisms adapted to a particular
niche had well developed specialised organs
• For example a carnivore will have long canine teeth to
grip its prey

18. vestigial organs
• Small non-functional organs (vestigial organs)
• e.g. the appendix in humans, the internal hind limbs of
whales and the internal legs of some species of snakes
• Comparative anatomy showed that these organs
resembled those which were much more developed, with
particular functions, in other species

19. The Law of Use and Disuse
• He proposed that if an organ is used a lot it will
develop and strengthen
• If it is not used it will atrophy
• He called this the law of use and disuse

20. The Inheritance of Acquired
Characteristics
• if an organism developed a characteristic feature through
adapting to a new way of life during its lifetime, it would
pass this on to its offspring
• The classic example given is that of the giraffe’s neck
• As the giraffe’s ancestors searched for a richer food supply
they stretched to reach higher branches in trees
• Thus their stretched bodies were passed onto their offspring

21. Lamarck v Darwin
• Lamarck’s theory required adaptation to create new variations
• This was followed by the inheritance of these characteristics
• Darwin’s theory requires random hereditary variation first,
followed by selection of the variations
• The argument was over when Mendel’s laws of genetics were
rediscovered at the end of the 19th century
• Variations are due to hereditary traits passing from one
generation to the next in predictable frequencies

22. Disproving Lamarck
• Characteristics acquired during the lifetime of a parent are not
passed onto the offspring
• Example: An athlete who develops a large muscle mass
through training does not have children who already possess
this large muscle mass
• Ernst Haeckel
In an attempt to disprove Lamarckism he is said to have cut off
the tails of mice for several generations
• The babies born from this line of tailless mice still grew tails as
long as their ancestors
• This was not exactly a fair test as the mice had not stopped
using their tails in an attempt to adapt to their environment
• They still found their tails useful

23. Lamarckism in evolution theory today
• Behaviour can be different
• Some behaviour patterns are innate and will also evolve in by
natural selection
• learned behaviour patterns can be changed within a
generation
• Members of a social group who have acquired the behaviour in
their lifetimes will pass these learned skills onto others
including their children
• This pattern of evolution resembles the Lamarckian pattern
• The evolution of learnt behaviour is much faster than genetic
evolution and it plays an important role in human cultural
evolution

24. Originators of Modern Theories of Natural Selection
Alfred Russell Wallace
Charles Darwin

25. Charles Darwin (1809-1882)
• Beagle voyage, 1831-36
• South America, Tierra del Fuego, Galapagos

26. • In 1831 Darwin sets sail on the HMS Beagle.
• In 1844 he writes his theory on the origin of species.
• In 1858, Darwin and Wallace publish their theories on
evolution.
• Evolution means change over time.

27. History of Darwin’s Studies
• Darwin went on an around-the-world trip on the HMS
Beagle and traveled to the Galapagos Islands.
• He particularly liked and observed the finches. He also
observed the tortoises on different islands.
• He observed each different group had its own niche.
• He studied 13 different species and saw how they
adapted to their environment.

28. 1859 On the Origin of Species by
Means of Natural Selection
Two theories presented in the book
1. Evolution = change in species over time;
descent with modification; new species derived
from other species; common ancestry.
2. Natural selection = main mechanism by which
evolution occurs.

29. Darwin’s evidence for evolution (species
derived from common ancestry)
• Geographical distribution & unique adaptations (13 similar
species of Galapagos finches)
• Fossils & long geological history.
• Vestigial organs.
• Taxonomic relations.

31. Key components of natural selection
• Variation
• Competition
• Fitness
• Adaptation
Variation
• Individual members of a species have heritable differences.
• Darwin hypothesized that these variations are random
(later term = gene mutations).

32. Competition: The struggle
for existence
• Resources are fixed (food, shelter).
• Many more individuals are produced each
generation than can survive and reproduce.
• Individuals must compete for limited resources.
• Darwin got this idea from reading Thomas Malthus
(1798), Principle of Population.

33. Grim doctrine of Rev. Malthus: pressure
of overpopulation. WHY?

34. Fitness of individuals
• Some individuals of a species have traits (physical
or behavioral) that make them better at surviving
and reproducing.
• Results in differential reproduction, or “survival of
the fittest.” The unfit perish or fail to procreate.
• Fitness is linked to particular environment.

35. Adaptation of the population
• Increased percentage of individuals in succeeding
generations have the beneficial traits.
• Results over time in a new population.
• Darwin called this “divergence,” we say speciation.

36. Darwin’s Finches - Geospiza
Galapagos tortoise - Geochelone

37. Contributing Elements to Darwin’s theory
1. Charles Lyell (1797 - 1875)
Gradualism (Uniformitarianism)
All change through time can be explained
by processes at work today
No need to invoke catastrophic events

38. Contributing Elements to Darwin’s theory
1. Charles Lyell (1797 - 1875)
2. Thomas Malthus (1766 - 1834)
Populations of organism will grow
faster than their food supply
Population
Food supply
Number
Time

39. Contributing Elements to Darwin’s theory
1. Charles Lyell (1797 - 1875)
2. Thomas Malthus (1766 - 1834)
3. Plant and Animal Breeders
-showed that the form of a
species could be changed
over time

40. Logic of Darwin’s
Theory of Natural Selection
(or Descent with Modification)
Observation Deduction
1. All organic populations can
exponentially.
2. In spite of Obs. 1, they don’t.
1. There is some kind of
struggle for existence.
3. All members of a species are
not the same.
4. Differences in individuals are
passed to their offspring.
2. Some members of a species
are better equipped to survive
and reproduce than others.
This differential reproduction/survival is
natural selection

44. Organising diversity:
Taxonomy and trees

45. So…..
What’s the reason some things are more similar than others?
Descent with modification from a common ancestor
What’s the mechanism?
Natural selection

46. Human
H. erectus
H. habilis
A. afarensis
Monkey ancestor
Chimp

47. Australopithecus afarensis
Lucy, 3 mya

48. Two legs good,
four legs bad?
So we can easily study how we look compared to our closet living
relative, cousin chimps but what did the common ancestor look like
and what do our human ancestors look like?
A. afarensis, nicknamed Lucy. Lucy lived partly in the trees like the
other apes and partly on the ground, walking around upright as we
do.

49. Gibbons swings by its arms and human run on 2 legs.
So easy to understand how living animals move because we can
watch them, but it is much harder to interpret how fossilsed animals
move, when we only have their bones to work out how they lived.
One technique is to look at the length of the humerus to the femur,
because the limb that is bigger is likely to be the one that does the
most work
When the animal is moving round.
We are going to test this theory by measuring some fossils that we
have here, and we need 2 volunteers to help Julia measure the fossil
bones (get volunteers)
and to get the human data the rest of us will measure ourselves.