Post on 05-Apr-2018
8/2/2019 darwins theory of evolution1
1/27
Mexican Tetra Sighted
8/2/2019 darwins theory of evolution1
2/27
www.carlwozniak.com
Basic premises for this discussion
Evolution is not a belief system. It is ascientific concept. It has no role in defining
religion or religious beliefs
Evolution is a theorybut you dont getany better than that in science
There is a lot of contention aboutevolution, but not among scientists orscientific organizations.
8/2/2019 darwins theory of evolution1
3/27
www.carlwozniak.com
Some basic definitions
Theory: a well-substantiated
explanation that incorporates facts,
laws, inferences and tested hypotheses.
In science, you dont get anybetter than a theory.
8/2/2019 darwins theory of evolution1
4/27
Darwins Theory of Evolution
8/2/2019 darwins theory of evolution1
5/27
Pre-Darwin
Lamarck (early 1800s)
Inheritance of Acquired
Characteristics
8/2/2019 darwins theory of evolution1
6/27
Inheritance of Acquired Characteristics
Why do giraffes have long
necks?
Because they stretch them
during their lifetime, then
their offspring have longnecks
The theory ofUse & Disuse
8/2/2019 darwins theory of evolution1
7/27
Who was Darwin?
Surgeon in training
Minister
Recruited by captain of HMS
Beagle
Set sail in 1831 at the age of 22
8/2/2019 darwins theory of evolution1
8/27
Not just the Galapagos
8/2/2019 darwins theory of evolution1
9/27
8/2/2019 darwins theory of evolution1
10/27
Darwin made 3 main observations
1. Members of a population vary in their
physical traits.
2. Many physical traits are inherited from
parent to offspring.
3. All species are capable of reproducing more
offspring than the environment can support.
8/2/2019 darwins theory of evolution1
11/27
And drew 2 conclusions:
1. Individuals who inherit traits that give
them a better chance of surviving tend to
leave more offspring than other individuals
2. This unequal reproduction of offspring
causes favorable traits to accumulate in a
population over generations.
(survival of the fittest; struggle for existence)
8/2/2019 darwins theory of evolution1
12/27
Darwin called these
conclusions Descent with
Modification
We call it Natural Selection
8/2/2019 darwins theory of evolution1
13/27
Important!!
What is favorable in one
environment may not be in another
environment.
The environment determines what isfavorable and unfavorable.
8/2/2019 darwins theory of evolution1
14/27
4 Take-home Points about Natural
Selection
1. Individuals DO NOT evolve.Evolution refers to generation-to-
generation changes in a population.
2. Natural selection can only amplify
or diminish traits that areinheritable.
8/2/2019 darwins theory of evolution1
15/27
4 Take-home Points about Natural
Selection
3. Evolution is NOT goal-directed.
No notion ofperfect species.
Environmental factors vary in place &timefavorable traits will also vary.
8/2/2019 darwins theory of evolution1
16/27
4 Take-home Points about Natural
Selection
4. Evolution is about compromise.
8/2/2019 darwins theory of evolution1
17/27
What Data did Darwin collect?
(i.e., what is the evidence for
evolution?)
1. Fossil Record
2. Biogeography
3. Comparative Embryology
4. Comparative Anatomy
5. Molecular Biology
8/2/2019 darwins theory of evolution1
18/27
GO TO EVIDENCE POWER POINT
8/2/2019 darwins theory of evolution1
19/27
A Skull of Homo erectusB Ammonite casts C Dinosaur tracks
Fossilized organicmatter of a leaf E Insect in amber
FIce Man
D
1. The Fossil Record
8/2/2019 darwins theory of evolution1
20/27
Pelvis andhind limb
Rhodocetus(predominantly aquatic)
Pakicetus(terrestrial)
Dorudon(fully aquatic)
Balaena(recent whale ancestor)
Pelvis andhind limb
8/2/2019 darwins theory of evolution1
21/27
2. Biogeography
All the species of
finches on the
Galapagos Islands
look like finchesnative to the West
Coast of South
Americabut not
exactly the same
Adaptive
Radiation
8/2/2019 darwins theory of evolution1
22/27
Pharyngealpouches
Post-analtail
Chick embryo Human embryo
3. Comparative Embryology
8/2/2019 darwins theory of evolution1
23/27
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
Human Cat Whale Bat
4. Comparative AnatomyHomologous Structures = Divergent Evolution
8/2/2019 darwins theory of evolution1
24/27
Pelvis andhind limb
Dorudon(fully aquatic)
Balaena(recent whale ancestor)
Pelvis and
hind limb
4. Comparative Anatomy
Vestigial Structures: What are left of
homologous structures
8/2/2019 darwins theory of evolution1
25/27
Dorudon
Balaena
8/2/2019 darwins theory of evolution1
26/27
Modern-Day Humpback Whale
8/2/2019 darwins theory of evolution1
27/27
Analogous Structures = Convergent Evolution
H
omologous
An
alogous