1. History of Earth Recap

2. 1. Important Terms:
A. Radioisotope – an unstable atom that breaks down and gives off energy in the form of radiation.
i. An important characteristic of all radioisotopes is that the amount of time it takes to breakdown is always the same.

3. 2. Important Terms:
B. Half-life – the time it takes for ½ of a given amount of radioisotopes to breakdown.

4. 3. How Life Began
A. Most scientists think that life on Earth developed through natural processes (spontaneous origin).
i. )Atoms that became energized, from the sun or volcanoes, reacted to form simple molecules.
ii.) Gradually these reacted to form more complex organic molecules.
iii.)Eventually they formed the first cell.

5. 2. B.Primordial Soup Model
i. Oparin & Haldane (1920) hypothesized that the early earth’s oceans once had lots of organic molecules that had been created in chemical reactions from the sun, lightning, or volcanoes.

6. 2.b.) Primordial Soup Model
ii. Miller & Urey (1953) tested this hypothesis by building an apparatus to simulate the conditions of the earth at that time.

7. 2. B. ii) Primordial Soup Model
SUCCESS!
1. The experiments produced amino acids and other organic compounds including ATP, lipids, sugars, RNA, and DNA.
2. The results indicate that the basic molecules essential for life could have arisen spontaneously in the early earth conditions.

8. C) Bubble Model
Lerman (1986) hypothesized that the key chemicals processes needed for life took place within bubbles on the oceans surface.

9. B) Bubble Model
ii. Simple molecules (ammonia, methane, etc.) were released from volcanoes underneath the oceans and together they traveled in bubbles to the surface.
iii. While traveling upwards they reacted together to create even more advanced molecules.

10. C) Bubble Model
Once at the surface they became airborne and exposed to UV light and lightning. This caused new reactions to occur and the molecules became more complex.
Afterward the more complex molecules fell back to the ocean and the process repeated.

11. D) Molecules Formed Cells
Cech & Altman (1980) showed RNA could be formed in water. (Heredity Information)
Simple observations show that lipids group together in water like oil in water. (Membranes)
Further examination shows that amino acids group together into microspheres. (Proteins)

12. D) Molecules Formed Cells
iii. All of these observations provide the framework from which the first cell could have arisen.
iv. However, the formal process as to how all of the pieces came together is of intense interest and research among scientists currently.

13. 3. Prokaryotes to Eukaryotes
Prokaryotes gave rise to eukaryotes through the process of endosymbiosis.
The mitochondria formed a partnership with other bacteria species. In exchange for protection, the mitochondria provided the host bacteria with energy.
B. From prokaryotes came Eukaryotes!

14. Prokaryotes to Eukaryotes

15. 3.C. Eukaryotes to Multicellularity
i. Eukaryotes then branched into four new kingdoms of more complex organisms:
1) Protists
2) Fungi
3) Plants
4) Animals
Cambrian Explosion
[540 mya to 505mya]

16. 4. Not all Organisms Survive
There have been 5 MAJOR MASS EXTINTIONS that have occurred on the Earth.
Mass extinctions are usually caused by a large ecological disaster.

17. 5. Life Invaded Land
a. 2.5 MYA, Cyanobacteria appeared and began to change the atmosphere on earth. They provided 03 for the Ozone layer (protect against UV rays from the sun) and 02 to make the Earth’s surface more habitable.

18. 5. B. Plants & Fungi Take Over The Land
Plants can do photosynthesis but cannot get minerals from bare rock.
Fungi can harvest minerals but cannot photosynthesize. The two form a mutual partnership called a mycorrhizae.

19. C. Arthropods Crawl Out Of Sea
Plants and fungi created habitats that could support (feed, protect) other organisms.
The first animals to successfully invade the land from the sea were arthropods (lobsters, crabs, insects, spiders, scorpions, etc.)
The insects have become the most plentiful and diverse group of animals in the history of the Earth.

20. D. Fish Evolve In The Sea
The first vertebrates (animals with backbones) were jawless fish.
The jaw formation helped fish bite and chew instead of suction up their food.
Fish became the most abundant animals in the history of the Earth making up about ½ of all vertebrates.

21. E. Amphibians Move Out Of Sea
The first vertebrates to inhabit the land were amphibians.
They were able to live in live on land because they had smooth skin and lungs, but their eggs needed water.

22. F. Amphibians Lead To Reptiles
Reptiles were new species of animals that arose from amphibians.
Reptiles had watertight skin and eggs that could survive on dry land.

23. G. Reptiles Take Flight, Grow Hair
Birds emerged from the reptiles and were able to populate new habitats.
Mammals also emerged from reptiles and were able to reproduce without laying eggs.

24. H. Mammals Take Charge
i. When the dinosaur (large reptile) extinction occurred 65mya it opened new chances for the mammals to emerge.

25. Evidence of Evolution
The Fossil Record

26. 6. How do changes happen? A. Mutations-changes in DNA
Types of mutations-
Point mutation ATACGTAAT-> AGACGTAAT
Frameshift TTACGTAGTTAG-> ATTTADGTAGTTAG
Insertion GATCATGGT-> GATCATAGGT
Deletion TATCATAGGT-> TATCTAGGT

27. How do we know that changes have been happening?
8. There is evidence from:
Fossils
DNA
Embryonic development

28. 9. The Fossil Record
A. Fossils of animals show a pattern of development from early ancestors to modern decedents.
i. Older fossils are found deeper in the ground.
Fossil is the preserved or mineralized remains or imprint of an organism that lived long ago

29. The Fossil Record
B. Darwin predicted that intermediate forms between the great groups of organisms would eventually be found.
i. Many of them have been found:
Fishes to amphibians
Reptiles and birds
Reptiles and mammals

30. The Fossil Record
10. Most scientists agree on the following three major points:
Earth is about 4.5 Billion years old
Organisms have inhabited the Earth for most of its history
All organisms living today share common ancestry with earlier, simpler life-forms

31. Dinosaur Eggs

32. 11. How do Fossils Form?
a. Most fossils form when organisms and traces of organisms are rapidly buried in fine sediments deposited by water, wind, or volcanic eruptions.

33. Woolly Mammoth Fossil

34. Tubeworm Fossil

35. What kind of Environment Is Needed?
11. b. The environments that are most likely to cause fossil formation are:
Wet lowlands
Slow-moving streams
Lakes
Shallow seas
Areas near volcanoes that spew out volcanic ash.

36. Age of Fossils A. Paleontologist: Scientists who study fossils
B. Determine aging by radiometric dating
Radiometric Dating- the estimation of the age of an object by measuring its content of a certain radioactive isotope.
Isotope- is a form of an element whose atomic mass differs from that of other atoms of the same element

37. 12. Age of Fossils
c. Certain rocks contain traces of potassium-40, an isotope of the element potassium.
When Potassium 40 decays, it produces two other isotopes; argon-40 and calcium-40
ii. Potassium is a chemical element in the periodic table that has the symbol K and atomic number 19. This is a soft, silvery-white metallic alkali metal that occurs naturally bound to other elements

38. 14. Anatomy and Development
A. Comparisons of the anatomy of different types of organisms often reveal basic similarities in the body structure even though the structure functions may differ between organisms

39. Vestigial Structures
Alligator /Human Fingers

40. b. Vestigial Structures
Sometimes bones are present in organisms that have not use or are less important as they are in other organisms
These structures are called vestigial structures
Examples: hind limbs of whales, snakes, the appendix and tailbone in humans…

41. Examples of Vestigial Structures

42. Whale Ancestry

43. 14. Anatomy and Development
C. Homologous Structures- are structures that share a common ancestry.
That is a similar structure in two organisms can be found in the common ancestor of the organism

45. Embryos
At some time in their development, all vertebrae embryos have a tail, buds that become limbs, and pharyngeal pouches

47. 15. Biological Molecules
ALL living things have DNA as their basic code…not just animals or groups like plants and animals.
As species evolved, they changes in their structures should stem from changes in their genetic instructions
Proteins – comparing the amino acid structure of a protein that is present in several species should show that the most related species have fewer differences than less related species
DNA sequences – DNA sequences in organisms tends to line up with evolutionary histories seen in the fossil record

48. Hemoglobin Comparison
Species
Amino Acid Differences from Human Hemoglobin Protein
Gorilla 1
Rhesus monkey 8
Mouse 27
Chicken 45
Frog 67
Lamprey
125

49. 16. Modern Science
As species evolves, one change after another should have become part of their genetic instructions.
Therefore, more and more changes in a gene’s nucleotide sequence should build up over time
Scientists can now compare proteins and nucleic Acids to determine how organism are related

50. Portions of skulls belonging to people who lived 160,000 years ago.