1. Origins of Biodiversity

2. Important Terms Important Terms
Evolution: A change in the gene pool of a population over time
Natural Selection: Process by which individuals that are better suited to their environment survive and reproduce more successfully.
Adaptation: An inherited characteristic that increases an organism’s chance of survival.

3. Charles Darwin

4. Charles Darwin

5. Charles Darwin Proposed the theory of evolution outlined in
The Origin of Species

6. Evidence of Evolution Fossil records Structure of DNA
Mechanisms of mutations

7. Natural selection as a possible driving force for speciation.
Evolution is the cumulative, gradual change in the genetic characteristics of successive generations of a species or race of an organism, ultimately giving rise to species or races different from the common ancestor.

8. Natural selection as a possible driving force for speciation.
Evolution reflects changes in the genetic composition of a population over time.

9. Natural selection as a possible driving force for speciation.
Natural Selection (Evolution) comes down to a species adapting to their surroundings over time.
A species with only plants to eat, will adapt to eating plants.
A species with only animals to eat, will adapt to eating animals.

10. Darwin's Research Studies 13 species of finches on Galapagos Islands
Looked a beak size and shape:
Stout beaks for eating seeds
Short and sharp beaks for eating insects.
Woodpecker-like beak for eating insects from trees, but instead of a long tongue it uses a cactus spine held in its beak to remove its prey.

12. Natural selection as a possible driving force for speciation.
Darwin’s theory of evolution by natural selection comes down to the following points:
Species show variation.
All species over-produce.
Despite over-production, population levels remain the same.
Over-production leads to competition for resources.

13. Natural selection as a possible driving force for speciation.
Darwin’s theory of evolution by natural selection comes down to the following points:
The fittest, or best adapted organisms, survive.
The survivors reproduce and pass on their adaptive genes to the next generation.
Over time, the population’s gene pool changes and new species emerge.

14. Natural selection as a possible driving force for speciation.

15. What is a species…
Species definition was made by humans, and fails to fully define nature.
These two ants look different are the same species of ant fulfilling different roles in a colony.
Pheidole barbata

16. Species definition is not always black and white Are we the same?+

17. Photo: Wiki Commons/GNU
ZONKEY
Photo: Wiki Commons/GNU

18. Isolation Geographical, behavioral, genetic, or reproductive factors.
If gene flow between the two sub- populations is prevented, new species may evolve.

19. This leads to geographic isolation
Speciation occurred on the earth over a very long period of time when the continents slowly drifted apart
This leads to geographic isolation
Continental Drift Animation

20. Isolation
The isolated population is an isolated gene pool since it does not breed with other populations.
The gene pool can therefore change as it adapts to the new conditions by natural selection. .

21. Isolation

22. Behavioral Isolation
Changes to the appearance or behavior of the populations
No longer attraction among the two types, and therefore no longer breed.

23. Reproduction Isolation
Two populations can no longer physically breed due to changes to reproductive organs.

24. Genetic Isolation
Too many genetic differences for the two populations to produce fertile young.

25. Northern population Arctic Fox Spreads northward and southward
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Gray Fox
Arctic Fox
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Southern population
Northern population
Spreads
northward
and
southward
separates
Early fox
population

26. Speciation
Read through your packet about Speciation

27. Plate Tectonics

28. Plate Tectonics PLATE = a portion of the Earth’s crust
TECTONICS = movement

29. Plate Tectonics
The Earth’s crust (lithosphere) is divided into many different plates.

30. Plate Tectonics
Plates are carried on the mantle (asthenosphere), which can flow like a liquid on a geological time scale.

31. Plate Tectonics
Edges of adjacent plates can either move parallel to one another, push one under the other, or collide.

32. Theory of Plate tectonics
Earth’s crust is broken into large pieces called plates

33. Theory of Plate tectonics
Plates move over time creating many landforms & geologic events such as earthquakes and volcanoes

34. Earth Through History
Because Earth’s plates are moving, the continents have not always been in their present location.

35. Earth Through History Pangaea – large supercontinent
As continents move apart – physical isolation may occur

36. Earth Through History
Geologic events – volcanoes & earthquakes can bring about loss of habitat and potential loss of species

37. Plate Tectonics
The movement of the major and minor plates in relation to one another is called plate tectonics.

38. Plate Tectonics
Movement of tectonic plates can produce barriers such as mountain ranges, oceans and rift valleys that can lead to isolation of gene pools and then speciation.

39. Types of Plate Movements
Convergent: pushed together
Divergent: moving apart
Transform: sliding past
What happens at plate boundaries can be constructive: building new land (ie: habitats) or destructive; destroying land

40. TRANSFORM BOUNDARIES Plates slide past with friction EARTHQUAKE ZONES
No new land or habitats

41. Divergent Physical separation of the plates Creates a rift
Rifts on land result in large lakes
Results in the formation of a physical barrier

42. Convergent Physical separation
Large changes due to mountains and islands

43. Convergent Boundaries (colliding)
3 Scenarios:
2 Continents Collide = folded mountains
Could lead to isolation – mountain range separates a population
Creates new habitat
Both constructive (building mountain) and destructive (one plate subducting)

44. Convergent Boundaries (colliding)
2 Oceanic Plates Collide
More dense plate subducts
Deep sea trench
Oceanic Islands
New Land formation = new habitat
Aleutian Island Arc: Possibility of future land bridge?? Affect on evolution & biodiversity?

45. Plate Tectonics
Land bridges can form from previously unconnected plates allowing species to spread.

46. Plate Tectonics
The movement of plates through different climatic zones allows new habitats to present themselves, and allow for different adaptations.

47. APPLY
Explain how plate tectonics has influenced evolution and biodiversity. Give specific examples.

48. Mass Extinction

49. Evolution Extinction
Extinction is the process by which a species, genus, or family, becomes extinct — no longer existing and living in the world
99% of all species that were on earth no longer exist

50. Mass Extinctions
There have been several major extinctions since the beginning of life 3.5 billion years ago

51. Evolution Extinction Background Extinction Mass Extinction
Not fit for the environment
Mass Extinction
More than ½ of the species extinct in 2 million years

52. End of Ordovician (440 mya)
2nd most devestating in Earth’s history
Effecting marine species
Probably due to glaciation
Source:

53. Late Permian (225 mya) Largest extinction
estimated that as many as 95% of all marine species were lost
Possible causes
continents merging to
form Pangea
global warming caused
by volcanic eruptions
glaciation
Source:

54. Cretaceous/Tertiary Extinction
All dinosaurs and half of other animals and plants went extinct. Possible asteroid
Brought about the rise of the mammals

55. Mass Extinction Plate Tectonics Super Volcanoes Climate Changes
Meteorite Impacts

56. 6th Extinction
There are have been at least 5 in the history of the Earth so far, and it has been well argued that we are currently in the midst of a 6th mass extinction event, the Holocene extinction, or alternately, the Anthropocene extinction

57. 6th Extinction Past extinction were geological and extra terrestrial
This is Human Caused.
Must shorter time period
Last year loss is compared to 2-3 million years

58. Discussion Question
Why does Australia have such strange animals??

59. Evolutionary Timeline of mammals
Platypus (Monotreme)
Dingo (Placental Mammal)
Kangaroo (Marsupial)