1. AP Biology
Macroevolution
Part 2

2. Modes of Speciation
Allopatric speciation
Sympatric speciation

3. Geographic Range of west coast salamanders (A ring species)

4. Galapagos Islands

5. Galapagos Islands close up

6. Darwin’s Galapagos Island finches

7. Modes of Speciation
Allopatric speciation
Sympatric speciation

8. Failure of cell division in a cell of a growing
Autopolyploidy
Failure of cell division
in a cell of a growing
diploid plant after chromosome duplication gives rise to a tetraploid branch or other tissue.
Offspring with tetraploid karyo-
types may be viable and fertile—a new biological species.
Gametes produced by flowers on this tetraploid branch are diploid. 2n
2n = 6
4n = 12 4n

9. Allopolyploidy Unreduced gamete with 4 chromosomes Unreduced gamete
Hybrid with
7 chromosomes
Viable fertile hybrid
(allopolyploid)
Meiotic error;
chromosome
number not
reduced from
2n to n
Species A
2n = 4
2n = 10
Normal gamete
n = 3
Normal gamete
n = 3
Species B
2n = 6

10. Stephen Jay Gould

11. .
Time
Gradualism model
Punctuated equilibrium model

13. Mass extinctions over time
Millions of years ago
600
500
400
300
200
100
100
2,500
Number of
taxonomic
families 80
2,000
Permian mass
extinction )
Extinction rate 60
1,500
Number of families (
Extinction rate ( 40
1,000
Cretaceous
mass extinction ) 20
500
Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous
Paleogene
Proterozoic eon
Neogene
Ceno-
zoic
Paleozoic
Mesozoic

14. Snowball Earth

15. Pangaea By about 10 million years ago, Earth’s youngest
major mountain range,
the Himalayas, formed
as a result of India’s
collision with Eurasia
during the Cenozoic.
The continents continue
to drift today.
Cenozoic
North America
Eurasia
By the end of the
Mesozoic, Laurasia
and Gondwana
separated into the
present-day continents.
65.5
Africa
South
America
India
Madagascar
Australia
Antarctica
Laurasia
By the mid-Mesozoic
Pangaea split into
northern (Laurasia)
and southern
(Gondwana)
landmasses.
135
Gondwana
Millions of years ago
Mesozoic
At the end of the
Paleozoic, all of
Earth’s landmasses
were joined in the
supercontinent
Pangaea.
251
Pangaea
Paleozoic

16. Asteroid Impact
NORTH
AMERICA
Chicxulub
crater
Yucatán
Peninsula

17. Example of Descent with Modification and Natural Selection

18. Evolution of the eye
Pigmented cells
(photoreceptors)
Pigmented
cells
Epithelium
Nerve fibers
Nerve fibers
Patch of pigmented cells
Eyecup
Fluid-filled cavity
Cellular
fluid
(lens)
Cornea
Epithelium
Optic
nerve
Pigmented
layer (retina)
Optic nerve
Pinhole camera-type eye
Eye with primitive lens
Cornea
Lens
Retina
Optic nerve
Complex camera-type eye