1. Evidence For Evolution

2. Sections Artificial Selection From Micro to Macro-evolution
Geologic evidence
Fossil evidence
Embryological evidence
Geographic evidence
Molecular evidence
Vestigial and Homologous structures
Addressing Illogical Arguments

3. Artificial Selection
Breeding for certain traits among plants and animals has been taking place for centuries.
Artificial selection takes the ‘natural’ out of ‘natural’ selection, and thus results in accelerated change.

5. Artificial Selection of Fruit Flies

6. If this kind of change within a species can be bred for in just a few centuries, what kind of change can take place naturally over millennia?

8. Micro-evolution
Even after as few as generations, substantial change has been observed and documented among species in the wild.
Natural selection results in observable change over time.

9. The Path from ‘Micro’ to ‘Macro’
Imagine the change that takes place as natural selection acts on species over millions and millions of generations….

10. Challenge question…
Why, evolutionarily speaking, are whales and dolphins are considered “Re-entrants.”
What other “re-entrants” can you name?

12. Geologic Evidence
Extensive geologic and environmental change is a prerequisite for macro-evolution.
Time, time, and more time is necessary to substantiate the argument of a common ancestry.
Without question, both of these prerequisites exist.

13. Radioactive Clocks: An Example
The half life of Carbon-14 is 5,730 years. Analyzing the amount of Carbon-14 remaining in a fossil indicates its age.
Here’s how…

16. Challenge Question:
The half life of Carbon-14 is 5,730 years. A hominid femur is recovered has mg of Carbon-14 present. If a living human of comparable size has a femur with 0.3 mg of Carbon-14 present, how old is the fossil?
How would you characterize this hominid?

18. Radioactive Clocks
With much longer half-lives, the radioactive decay of Uranium-238 and Potassium-41 provide undeniable proof of the age of igneous rock on Earth’s surface.
According to these radioactive clocks, the Earth is 4.6 Billion years old.

19. The Fossil Record
Contrary to popular (uninformed) opinion, a rich and detailed fossil record exists which dates back countless fossil remains of plants and animals up to 600 million years old.

20. The fossil Record (cont.)
Many fossils provide key evidence of a common ancestry and are often referred to as “links” or “intermediates.”
Here are just a few…
archaeopteryx

21. Eusthenopteron
395 mya

22. Tiktaalik
375 mya

23. Ichthyostega
370 mya

25. Human Evolution
Molecular evidence tells us the common ancestor humans share with chimpanzees lived 6 million years ago.
The most famous of many intermediates, Australopithecus Afarensis, or “Lucy” lived 3.6 million years ago.

26. Out of Africa…
Homo Ergaster
Approx 2
M.Y.A.
Extensive fossil evidence tracks the evolution of our bipedal ancestors out of Africa.
Homo sapiens and Homo erectus were soon to follow as just 2 of numerous transitionary species.

29. Living Fossils: Right Before Our Eyes…
coelacanth
Lungfish
A few species have existed millions of years with little to no evolutionary change, windows into our evolutionary past.
Ginko
Scorpionfly

30. Embryological evidence
During embryonic development, vertebrates and other animals show similarities in their embryos
Many vertebrate embryos show gill slits and tails although they don’t fully develop, strongly suggesting a common ancestor from which all modern animals evolved.

32. Biogeographic Evidence
Biogeographic zones are separated by physical barriers (seas, mountains, rivers, etc).
This physical separation prevents organisms from interbreeding while different selection pressures lead to speciation.

35. Galapagos Tortoises

36. Biochemical Evidence
Recent technological advances have allowed comparison of organisms on a molecular basis.
The amino acid sequences making up universal proteins like Cytochrome C and hemoglobin have remarkable similarity among all organisms.
…Again, what does this suggest?

37. DNA Evidence
DNA sequencing and comparison of various genes aid researchers in classifying modern animals and their ancestry.

38. Hox Genes
Hox genes are a group of related genes that “General purpose” control genes are important elements in building complicated organisms like flies. Some “control” genes are common to many organisms (they are homologous—inherited from our common ancestor).
For example, Hox genes help lay out the basic body forms of many animals, including humans, flies, and worms.

39. Did you know…
According to a comparative, gene by gene DNA analysis, chimpanzees and humans were found to be 98% identical.

40. Vestigial Structures
Challenge Question: Can you explain the significance of these structures? What were they used for?

41. Homologous Structures
The skeletons of vertebrates (especially within classes) are essentially identical.
selection pressures have made the bones themselves different.

42. Same Skeletal Structure
Swimming
Grasping
Running
Flying
Different Selection pressures

43. Did You Know?
The Giraffe and the Okapi are living mammals that share a recent common ancestor.

45. Illogical Argument #1
“If humans evolved from apes, why are there still living apes?”
Humans did not evolve from apes. We share a common ancestry with apes.

47. Illogical Argument #2
“If evolution is true, why are there so many gaps in the fossil record?”
This statement could not me more false. Sedimentary rocks have yielded countless “intermediates” which support a common ancestry among all animals.

49. Illogical Argument #3
“The ‘perfection’ and complexity we see in nature can only be the product of design…”
Living things are far from perfect. Complexity is a product of specialization, brought upon by natural selection and time.

50. Illogical Argument #4
“ I get ‘Micro-evolution,’ but ‘macro-evolution’ is just doesn’t make sense…”
3.5 Billion years, a proof-positive mechanism, and undeniable, overwhelming evidence…
….What more do you need?

52. That’s All Folks!
More to come…