Evolutionary History and Evidence

1. CHAPTER 4
EVOLUTION :
HISTORY AND
EVIDENCE

3. Organic evolution
- “ descent with modification “
Population
- consist of individuals of the same species
that occupy a given area at the same time.
- share a unique set of genes

4. PRE- DARWINIAN THEORIES
OF CHANGE
EMPEDOCLES ( 495 – 435 B.C. )
- described concepts of
change in living
organisms over time.

5. ARISTOTLE ( 384 – 322 B.C. )
- Discovered the
principle of nature by
analyzing accidental
changes or motion.

6. GEORGES LOUIS LECLERC COMTE BUFFON
( 1707 – 1788)
- Spent many years
studying comparative
anatomy.
- Believe in a special
creation of species
and

7. ERASMUS DARWIN ( 1731 – 1802 )
- Grandfather of Charles
Darwin
- Interested in question of
origin and change
- Believed in the common
ancestry of all organism

8. JEAN BAPTISTE LAMARCK ( 1744 – 1829 )
- His theory was based on
a widely accepted theory of
inheritance
- Believed that need was
dictated by environmental
change and that change
involved movement toward
perfection

9. DARWIN’S EARLY YEARS AND
HIS JOURNEY
CHARLES ROBERT DARWIN (1809 – 1882 )
- Born on February 12,
1809
- His interest centered
around dogs, collecting,
and hunting birds
- He entered medical
school in Edinburgh,
Scotland
- He trained for clergy in
the Church of England

10. VOYAGE OF THE HMS
BEAGLE

11. EARLY DEVELOPMENT OF DARWIN’S
IDEAS OF EVOLUTION
Geology
 Charles Lyell
 James Hutton
- theory of uniformitarianism
- based on the idea that the forces of wind, rain,
rivers, volcanoes and geological uplift shape the earth today.
This book planted two important ideas in Darwin’s mind:
1. The earth could be much older than 6,000 years
2. If the face of the earth changed gradually over long periods,
could not living forms also change during that time?

12. FOSSIL EVIDENCE
TOXODON
THOANTHERIUM

13. GIANT ARMADILLOS
GIANT SLOTH

14. GALAPAGOS ISLAND

17. ADAPTIVE RADIATION
- THE FORMATION OF NEW FORMS FROM AN
ANCESTRAL SPECIES

18. THE THEORY OF EVOLUTION BY
NATURAL SELECTION
Thomas Malthus
- Essay on the Principle of Population
- believed that the human population has the potential to
increase geometrically.
Natural Selection
1. All organism have a far greater reproductive potential than is ever
realized.
2. Inherited variations exist.
3. Because resources are limited, existence is a constant struggle.
4. Adaptive traits are perpetuated in subsequent generations.

19. ADAPTATION
- occurs when a change in a phenotype increases a
animal’s chance of successful reproduction.
Alfred Russel Wallace
- led zoological expediton to the Malay Achipelago
- synthesized a theory of evolution similar to Darwin’s
theory of natural selection

20. MICROEVOLUTION
-a change in the frequency of alleles in population
over time.

21. MACROEVOLUTION
-large scale changes that result in extinction and the
formation of new species.

22. EVIDENCE OF
MACROEVOLUTIONARY
CHANGE
1. Patterns of plant and animal distribution

23. 2. Fossils

24. 3. Biochemical molecules

25. 3. Anatomical structures

26. 5. Developmental patterns

27. BIOGEOGRAPHY
-study of the geographic distribution of plants and
animals.

28. BIOGEOGRAPHERS
TRY TO EXPLAIN:
1. How similar group of organisms have dispersed to places
separated by seemingly impenetrable barriers.
2. Why plants and animals, separated by geographical
barriers are often very different inspite of similar
environments.
3. Why oceanic islands often have relatively few, but
unique, resident species.

29. PALEONTOLOGY
-study of the fossil record, which provides some of
the most direct evidence for evolution.
FOSSILS- evidence of plants and animals that existed in the
past and have become incorporated into the earth’s crust.

31. Homology
- the two different organisms are similar in structure
and function because they share a common ancestry

32. COMPARATIVE ANATOMY
- the comparative study of the body structures
of different species of animals
- the study of the structure of living and
fossilize animals and the homologies that indicate
evolutionary close relationship

33. MOLECULAR BIOLOGY
- branch of biology that deals with the
molecular basis of biological activity
- chiefly concerns with understanding the
interactions between :
*the various systems of the cell
*DNA, RNA and protein biosynthesis

34. DEVELOPMENTAL PATTERNS
• Developmental stages of related animals often retain
common features.
• Early embryonic stages of vertebrates are remarkably
similar.
- many organ system of the vertebrates also show
similar developmental patterns
• Differences in adult stages arise as a result of
evolutionary genes that control the onset of
developmental stages and the rate at which development
occurs.

36. INTERPRETING THE EVIDENCE:
PHYLOGENY AND COMMON DESCENT
Phylogeny
- refers to the evolutionary relationships among species
- the depiction of ancestral species and the relationships of
modern descendants of a common ancestor