The theory that organisms today developed from more simple life forms and have changed (evolved) over time.

1. LIBERALART
of SCIENCES
“THEORY OF
EVOLUTION”
Lecturer: Taalai Mambetov

2. EVOLUTION
The theory that organisms
today developed from
more simple life forms and
have changed (evolved)
over time.

3. A new era of biology began
in 1859 when Charles Darwin
published The Origin of
Species
The Origin of Species
focused biologists’ attention
on the great diversity of
organisms
Darwin noted that current
species are descendants of
ancestral species
Evolution can be viewed as
both a pattern and a process

4. Charles Darwin
1809 - 1882

5. Scale of discovers

6. Evolution
Pre-
Darwin
Beliefs
Creationism
Catastrophis
m
Lamarckism Gradualism

7. Evolution
Pre-Darwin
Beliefs
• Jean Pierre Lamark
believed that organisms
can change their traits
during their lifetime by
use or disuse.
• He thought that these
traits are passed on to
offspring. Over time
this would cause
change in a species.

8. Darwin’s
Research
• As a boy and into adulthood,
Charles Darwin had a consuming
interest in nature
• Darwin first studied medicine
(unsuccessfully), and then
theology at Cambridge University
• After graduating, he took an
unpaid position as naturalist and
companion to Captain Robert
FitzRoy for a 5-year around the
world voyage on the Beagle

9. The Voyage of
the Beagle
• During his travels on the
Beagle, Darwin collected
specimens of South American
plants and animals
• He observed that fossils
resembled living species from
the same region, and living
species resembled other
species from nearby regions
• His interest in geographic
distribution of species was
kindled by a stop at the
Galápagos Islands west of
South America
• He hypothesized that species
from South America had
colonized the Galápagos and
speciated on the islands

11. Voyage of the Beagle
What did Darwin find?
 The finches on each island in the Galapagos
had different types of beaks.
(a) Cactus-eater (b) Insect-eater
(c) Seed-eater

12. Voyage of the Beagle
What did Darwin find?
The tortoises on each island in
the Galapagos had different types
of shells.

13. hypothesis?
 Darwin
hypothesized that
organisms had a
common ancestor,
but had adapted
to their particular
environments and
changed over time.
 Darwin published
his research in
1859.

14. Artificial Selection,
Evolution and
Natural Selection

15. Evolution & Natural
Selection
• Genetic variations are
passed on through
reproduction
• Evidence for evolution
illustrates how organisms are
related
• Natural selection leads to
evolution
• Our understanding of
evolution has changed
over time

16. Artificial Selection
Darwin noted that humans have
modified other species by
selecting and breeding individuals
with desired traits, a process
called artificial selection.
Darwin drew two inferences from
two observations:

17. Observation #1:
Members of a
population often
vary in their
inherited traits

18. Spore
cloud
Observation #2: All species can produce more offspring than the
environment can support, and many of these offspring fail to
survive and reproduce

19. Natural Selection
The theory that states
that those organisms best
adapted to their
environment have a
better chance of surviving
and reproducing.

20. Natural Selection
For natural selection to occur, there
must be at least two varieties of a
species.
For example: the peppered moth

21. Peppered Moths
At the beginning of the Industrial Revolution in
England, coal burning produced soot that covered
the countryside in many areas

22. What do you think happened?

23. Evolution/Natural Selection
White moths became
easier to see, while
the black moths
became harder to see.
The black moths were
more likely to survive
and pass on the gene
for dark color to their
offspring.
Over time, the black
moths have become
more.

24. (a) A flower mantid in Malaysia (b) A leaf mantid in Borneo

26. Evidence for
Evolution:
Common
Ancestry
Over time, their common ancestor evolved into
several species, each with a specialized beak for
eating certain foods. Just like Darwin’s finches
on the Galapagos!
Common Ancestry:
If species evolved from a common ancestor, then
they should share common anatomical traits
Hawaiian Honeycreeper: family of birds in
Hawaii that have similar skeletons and
muscles, indicating they are closely related.

27. Evidence for
Evolution:
Homologous
Structures
If animals evolved from a
common ancestor, then
they should share
common structures – and
they do!
These are
called
homologous
structures

28. Evidence for evolution: Embryo
Development
What do you
notice?

29. Evidence for Evolution:
Vestigial Organs
• Some organisms have
structures or organs
that no longer have a
useful function.
• These structures or organs
may have been useful to
the ancestors of a species,
but over time have evolved
into what we term vestigial
organs.

30. Examples of Vestigial Organs
 Kiwi (flightless bird)
 Whales (hind leg bones)
 Humans (tailbone, appendix)

31. Evidence for Evolution Fossils
 Fossils provide a
look into the past.
 Scientists can trace
how a species has
evolved by studying
fossils.

32. Wrap Up
the
Evidence
Common Ancestry
Homologous Structures
Vestigial Organs
Embryonic Development
Fossils