1. Theories on the Origin of Life
Spontaneous generation is the theory that life can come from non-living matter. (Frogs come from mud, flies come from garbage, etc.)

2. Disproved by Redi (1600) – covered materials don’t produce flies.

3. Maggots are – larvae stage of a fly

4. Spontaneous generation of microbes was disproved by Louis Pasteur (1860)- theory of biogenesis - life come from life

5. Miller and Urey experiment (1953) formed amino acids
Heterotroph Hypothesis–
life arose from a combination of inorganic chemicals
methane (CH4), ammonia (NH3) + water (H2O) that existed in the ancient
oceans of earth.
Miller and Urey experiment (1953) formed amino acids
Fox – amino acids will form proteins at high temperatures
Proto- cells formed

6. Darwin & Evolution by Natural Selection
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
finch
Tree finches
Ground finches

7. Charles Darwin Proposed a way how evolution works
How did creatures change over time?
by natural selection
Collected a lot of evidence to support his ideas
British naturalist
What did Darwin say?
What evidence supports Evolution by Natural Selection?
What impact did Evolution have on biology?

8. Voyage of the HMS Beagle
Invited to travel around the world
(22 years old!)
makes many observations of nature
main mission of the Beagle was to chart South American coastline
After graduation Darwin was recommended to be the conversation companion to Captain Robert FitzRoy, preparing the survey ship Beagle for a voyage around the world.
FitzRoy chose Darwin because of his education, his similar social class, and similar age as the captain.
Darwin noted that the plants and animals of South America were very distinct from those of Europe
Robert Fitzroy

9. Voyage of the HMS Beagle
Stopped in Galapagos Islands
500 miles off coast of Ecuador
The origin of the fauna of the Galapagos, 900 km west of the South American coast, especially puzzled Darwin.
On further study after his voyage, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland.
It seemed that the islands had been colonized by plants and animals from the mainland that had then diversified on the different islands

10. Galapagos
Recently formed volcanic islands. Most of animals on the Galápagos live nowhere else in world, but they look like species living on South American mainland.
800 km west of Ecuador

11. Darwin found…many unique species
Many of Darwin’s observations made him wonder… Why?
Darwin asked:
Why were these creatures found only on the Galapagos Islands?

12. Darwin found…clues in the fossils
present day Armadillos
Darwin found…clues in the fossils
Darwin found:
Evidence that creatures have changed over time
ancient Armadillo
Darwin asked:
Why should extinct armadillos & modern armadillos be found on same continent?

13. Darwin found… more fossils
present day Sloth
Darwin found… more fossils
Darwin found:
Evidence that creatures have changed over time
(extinct) Giant ground sloth
Darwin asked:
Why should extinct sloths & modern sloths be found on the same continent?

14. Darwin found: Different shells on tortoises on different islands
Darwin asked:
Is there a relationship between the environment & what an animal looks like?

15. Darwin found… birds Darwin found:
Finch?
Sparrow?
Woodpecker?
Warbler?
Darwin found:
Many different birds on the Galapagos Islands.
He thought he found very different kinds…
Finch?
Sparrow?
Woodpecker?
Warbler?

16. But Darwin found… a lot of finches
Darwin was amazed to find out:
All 14 species of birds were finches…
Finch?
Sparrow?
Woodpecker?
Warbler?
But there is only one species of finch on the mainland!
Large ground finch
Small ground finch
Finch?
Sparrow?
Darwin asked:
If the Galapagos finches came from the mainland, why are they so different now?
Warbler finch
Tree finch
Woodpecker?
Warbler?

17. The finches cinched it! different beaks are inherited variations
serve as adaptations that help birds compete for food
these birds survive & reproduce
pass on the genes for those more fit beaks
over time nature selected for different species with different beaks
Darwin found:
The differences between species of finches were associated with the different food they ate.
Finch?
Sparrow?
Woodpecker?
Warbler?
Darwin said:
Ahaaaa! A flock of South American finches were stranded on the Galapagos…
Large ground finch
Big seed eater
Small ground finch
Small seed eater
Insect eater
Warbler finch
Leaf & bud eater
Tree finch

18. Relationship between species (beaks) & food

19. Darwin’s finches Darwin’s conclusions variations in beaks
differences in beaks in the original flock
adaptations to foods available on islands
natural selection for most fit
over many generations, the finches were selected for specific beaks & behaviors
offspring inherit successful traits
accumulation of winning traits: both beaks & behaviors
separate into different species

20. From 1 species to 14 species…
Warbler finch
Woodpecker finch
Small insectivorous
tree finch
Large
insectivorous
Vegetarian
Cactus finch
Sharp-beaked finch
Small ground
finch
Medium
ground finch
Large ground
Insect eaters
Bud eater
Seed eaters
Cactus
eater
Warbler
Tree finches
Ground finches
natural selection for best survival & reproduction
variation

21. Earlier ideas on Evolution
LaMarck
evolution by acquired traits
creatures developed traits during their lifetime
give those traits to their offspring
example
in reaching higher leaves giraffes stretch their necks & give the acquired longer neck to offspring
not accepted as valid

22. Darwin’s view of Evolution
giraffes that already have long necks survive better
leave more offspring who inherit their long necks
variation
selection & survival
reproduction & inheritance of more fit traits 

23. Darwin’s Theory of Natural Selection
#1 Overproduction
Organisms tend to have many more than two offspring so at least some will survive (yet populations usually do not grow rapidly in the wild)

24. #2 Competition - Therefore they
must compete for resources
(food, space, mates)

25. Natural Selection #3 Variation - variation within the population.
#4 Adaptation - Therefore some of them must be better adapted to their environment

26. Sources of Variation A. Mutation
A mutation is a change in the DNA of an organism due to external or internal factors. (toxins, radiation, random,etc.)
Most mutations are NOT beneficial to the organism.
Some may become beneficial if the environment changes, provided they do not harm the individual. (ex. Giraffe’s neck)

27. #5. Natural Selection- the ability of organisms that are best adapted to survive and reproduce . Those that are less adapted will not survive.

28. Speciation
Eventually, over generations and time, new species will evolve from older forms by natural selection of better adapted forms.

30. Divergent Evolution

31. Evidence for Evolution All of the fields of Life Science show evidence of evolution.
A. The Fossil Record
Fossil: the remains or evidence of past life recorded in rock.
(molds, impressions, bones, shells, teeth, preserved in ice, etc.)
1. Fossils are found most often sedimentary rock.
2. Relative age can be determined by the fossils position in the layers. The oldest fossils are found below the younger ones.

32. 3. Absolute dating uses the principal of radioactive dating
The half-life of known radioactive compounds never changes.
(ex. Carbon 14 found in bones and shells can determine their actual age in years).
Ex. Fossil remains clearly show the gradual evolution of the modern horse.

33. B. Comparison of Similar Anatomy or Structures
1. Homologous structures - those that appear to have come from a common ancestor. These indicate that species are related.
Ex. Bats wing, human arm and whale flipper bones.

34. 2._ananlogous__________ structures that are used for the same function but are not similar. These indicate species are not related.
Same function different structure

35. vestigial _______-
a structure, or organ, that appears to have lost all, or most, of its functions

36. Comparative Anatomy

37. Comparative Embryology
Comparative Embryology – examination of differences and similarities in embryo development (before birth).
ex. Comparison of bird, fish and early human embryos

38. Biochemical Comparisons
Recent developments (Human Genome Project) have allowed for the comparison of DNA from different species and groups within species. This new evidence is the strongest yet that consistently supports accepted evolutionary theory.
DNA - our DNA and that of a Chimpanzee is more than 99% identical. Gorillas and Baboons have somewhat less (95-97%) and mice have 80% identical DNA.
Ex. Cytochrome C, a respiratory enzyme common to all animals is slightly different in different species. Humans differ from monkeys by one amino acid in their cyt C. We differ from pigs by 10 amino acids. Chicken cyt C has 13 different amino acids and fish differ by 21. This clearly shows the accepted evolutionary relationship between vertebrates. F.

39. Asking Questions is a good adaptation!