1. Earth’s Historical Highlights
Major stages in the history of Earth
Major Extinctions

2. The Beginning Earth is formed from dust and debris orbiting the sun
A process named Accretion
Like snowballing
~4.6 BYA
(billions of years ago)
Then the crust formed

3. This whole time is simply called
The Eons of Time
Eons divided into Eras divided into Periods (what was going on)
COMPLEX
LIFE
Millions of Years Ago
Phanerozoic
Eon
Cenozoic era
Quaternary, Tertiaray
Mammals
200
Mesozoic era
Cretaceous, Jurassic, Triassic
Reptiles, birds
400
Paleozoic
Permian, Carboniferous, Devonian
Fish, amphibians
600
Silurian, Ordovician, Cambrian
Invertebrates
800
Proterozoic
Single Cells & colonial
Neoproterozic
Ediacaran, Cryogenian, Tonian
Stenian,
Ectasian,
Calymmian
1000 MYA (1 BYA)
Mesoproterozic
1200
Colonial Organisms?
1400
1600
1800
Paleoproterozoic
Statherian
Orosirian
Rhyacian
Siderian
2000 MYA (2 BYA)
2200
2400
Eukaryotes?
2600
Archean Eon
Bacteria only
Neoarchean
(not yet divided into periods)
2800
Meoarchean
3000 MYA (3 BYA)
Paleoarchean
3200
Eoarchean
Bacteria?
3400
Hadean Eon
No Life
Early Imbrian
Bombardment ends
3600
Nectarian Era
Earth cools, Oceans form
3800
Basin Group Era
cometary bombardment!
4000 MYA (4 BYA)
Cryptic Era
Sun & Planets form
MICROSCOPIC LIFE
In Your Textbook
This whole time is simply called
Precambrian
BACTERIAL LIFE
NO LIFE
This scale of years is approximate, and may vary from other sources by a million years or so

4. Geological Timetable Era From/to events periods Ends with Cenozoic
“Age of Mammals”
Now
Mammals
birds
Quaternary
65mya
Tertiary
Mesozoic
(middle animals)
“Age of Reptiles”
65 MYA
Dinosaurs
Early mammals Reptiles
Cretaceous
Jurassic
250 MYA
Triassic
Paleozoic
(ancient animals)
“Age of Invertebrates”
540 MYA
Early reptiles
Amphibians
Insects, mollusks
trilobites
Permian
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Earlier Eras
“Precambrian”
4 BYA
bacteria, etc First Life,. Earth cools
Pre-cambrian
See previous slide 5 4 3 2 1

5. ERAS (simplified)
Cenozoic Era: Our era… lots of mammals, birds, flowering plants
Mesozoic Era: Age of reptiles. Dinosaurs and other large reptiles, gymnosperm plants
Paleozoic Era: Age of invertebrates. Molluscs, insects, trilobites, worms etc. Algae and mosses.
“Precambrian”: Age of microscopic life. Bacteria and some protozoans. Algae and cyanobacteria

6. The Major Eras Life begins ~3.8bya Beginning of Precambrian Era
Bacteria and prokaryotes appear

7. Palaeozoic Era “the age of invertebrates”
paleo/old + zoic/animals = ancient life
There was only one continent at the beginning
Rodinia (the mother continent)
The land started off cold, but the seas warmed up quickly
Life proliferates
Extensive variety of sea life
The predominant animal forms were invertebrates (animals without backbones) like trilobites, insects, squids, snails etc.
Then most life dies at the end of the Palaeozoic

8. PALEOZOIC ERA The “age of invertebrates”
The Paleozoic Era started about 543 million years ago, and lasted nearly 300 million years
(until 245 million years ago)
During the Paleozoic Era life proliferated. Many new and strange creatures populated earth’s oceans– sponges, molluscs, trilobites, worms etc.
Predominant life forms were invertebrates (no backbones)
The Paleozoic era is divided into six periods

9. PALEOZOIC ERA: Part I The Cambrian Period (540 MYA)
There was only one continent at the beginning
Rodinia: the first supercontinent (the mother continent)
Most life was aquatic (ocean life)
Sponges (formless animals)
Jellyfish (soft aquatic animals
Tiny molluscs (snails, clams)
Marine Worms
Tiny mollusc shells from Cambrian Period (early Paleozoic)

10. PALEOZOIC ERA: Part II The Ordovician Period
The supercontinent began to break apart
Into Gondwana ,Laurentia and Baltica
Africa, South America
Antarctica & India
North America
Europe
Common life forms included:
Trilobites (ancient arthropods)
Jawless Fish (eels)
Cartilage Fish (ancestors of sharks)
Plants and animals began to colonize the land

11. PALEOZOIC ERA: Part III
Silurian Period ( MYA):
Plants spread across the land
Mostly mosses and primitive fern ancestors.
No really big trees yet

12. PALEOZOIC ERA: Part IV Devonian Period: (409-363 MYA)
First amphibians appeared
First insects appeared
Plants became larger and more varied
Underwater, fish were becoming larger and more diverse

13. PALEOZOIC ERA: Part V The Carboniferous era (363-290 MYA)
AKA: Mississippian/Pennsylvanian Era
Great forests covered the land.
Much of our fossil fuel (coal and oil) comes from plants that died in the carboniferous period.

14. PALEOZOIC ERA: Part VI Permian Period. (290-245 MYA)
By the end of the Paleozoic era, some of the continents had rejoined, forming a new supercontinent called Pangea.
More varied reptiles appeared.
Dimetrodon
The Permian period ended with the greatest of all mass extinctions.
90% of aquatic life became extinct
75% of terrestrial life
This also brought the paleozoic era to an end.

15. The Palaeozoic Earth

17. End of the Palaeozoic
Although the palaeozoic era is called the “age of invertebrates”, towards the end of the era some primitive fish, amphibians and reptiles had evolved.
A mass extinction occurred to end the era.
We can identify mass extinctions in the fossil record by finding a layer with very few fossils just above a layer with lots of fossils.
This extinction was one of the biggest:
95% of marine life and 75% of land life disappeared.

18. The Mesozoic Era: Age of Reptiles
Meso/middle + zoic/animal = middle animals
AKA the Dinosaurs’ era
Albertosaurus

19. Mesozoic Earth

20. Periods of the Mesozoic Era
Triassic Period:
Dinosaurs appeared
Jurassic Period
Dinosaurs grew larger and more diverse. Small mammals and primitive birds may have developed
Cretaceous Period
Pangea broke up into the modern continents
The largest dinosaurs appeared

22. The End of the Mesozoic Era
The Mesozoic era ended when a large asteroid smashed into Mexico, about 65 million year ago.
The dinosaurs and many other life forms became extinct during the climate changes that followed.
This was the 5th mass extinction

23. Cenozoic Era: The age of Mammals
Known for the success and diversification of mammals

24. Periods of the Cenozoic Era
Tertiary period: there were many large and unusual mammals
Quaternary Period: primates and hominids evolved

25. The Quaternary Period (Periods are smaller divisions of Eras)
Known for global glaciations
Ice ages
Modern man has been evolving for
Over a million years (perhaps as much as three million years)
But has been sedentary for only ~10000 years
civilized

26. Chapter 17: Human Evolution

27. Hominid Fossils
Humans and some of their extinct relatives belong to a family known as hominids.
Hominids are classed within the order primates, along with apes and monkeys.
The oldest hominid fossils have been found in Africa.
“Lucy” a hominid fossil from
About 3 million years ago

28. The complete classification of humans is:
Kingdom Animalia (animal kingdom)
Phylum Chordata (chordates have a notochord)
Subphylum Vertebrata (with proper backbone)
Superclass Tetrapoda (decendants of four-limbed vertebrates)
Class Mammalia (the mammals)
Subclass Theria (live-birth mammals),
infraclass Eutheria (placental mammals)
Order Primates (the primates: monkeys, apes, hominids)
Superfamily Hominoidae (anthropoids, greater apes)
Family Hominidae (the hominids: humanlike. All other hominids except humans are now extinct)
Genus Homo (Humans and early humans)
Species sapiens (Modern “wise” humans)
This is presented for your information. You don’t need to copy or memorize it

29. The First Hominid? A newly discovered fossil
Ardipithicus ramidus (Ardi): a chimpanzee sized hominid found in Africa and dated to about 4.4 million years, making it the oldest nearly intact hominid skeleton ever found.
On October 1, 2009, paleontologists formally announced the discovery of the relatively complete A. ramidus fossil skeleton first unearthed in The fossil is the remains of a small-brained 50-kilogram (110 lb) female, nicknamed "Ardi", and includes most of the skull and teeth, as well as the pelvis, hands, and feet

30. Some Other Identified Hominid Species
Australopithicus afarensis “Lucy” is a species found in the Afar valley of Africa. They lived between 3 million and 4 million years ago
Australopithicus africanus, Taller and heavier than “Lucy” lived in Africa between 2.3 and 3 million years ago
Paranthropus* robustus and Paranthropus* boisei “nutcracker man” both lived between 1 and 2 million years ago in Africa
Australopithicus
Paranthropus
* These two were formerly placed in genus Australopithicus

31. More Identified Hominid Species
Homo Habilis “Handy Man” lived in Africa about 2.5 million years ago. This fossil used tools and may be the earliest representative of the human genus.
Homo Erectus, “upright human” was first discovered in Java, and since then all over Asia, Africa and Europe. This may well be the ancestor of modern humans. They existed from 1.8 million years ago to as recently as 40,000 years.

32. Two Modern Human Species
Homo neanderthalensis (or possibly Homo sapiens- neanderthalensis) lived in Europe from about 1.8 million years ago to as recently as 30,000 years ago. It has not been established if this was a separate species of human, or a “race” that would be capable of breeding with “modern” humans (hence the disputed classification)
The most recent evidence is that these two types of human were different species, so I will use the terms homo sapiens and homo neanderthalensis

33. Homo sapiens (or perhaps Homo sapiens sapiens) is the designation of modern humans. The first fossils of modern humans were found in the Cro-magnon caves in southern France.
Because of where they were first found, early homo sapiens are occasionally referred to as “Cro-magnon man”. This is not an official designation, as they were undoubtedly the same species as modern man.

34. Some lesser-known and disputed hominid fossils
Homo Floresiensis? “hobbit”: a very small hominid fossil recently found in Malasia dating to about years ago. Its authenticity is still under dispute. It may be a malformed human.
Homo Heidelburgensis “Goliath” is a large fossil homind found in Germany. It may be a separate species or a variety of Neanderthal, Homo Erectus or Antecessor
Homo Antecessor is a fossil found in Spain which may be an ancestor of both Neanderthals and modern humans, or it may simply be a variety of Neanderthal or Homo Erectus

35. Hominids (Human Ancestors)
4 million
Years ago
3 million
Years ago
2 million
Years ago
1 million
Years ago
Now |
Ardi
Lucy
“Nutcracker” man
Ardipithicus sp.
Australopithicus sp.
Paranthropus sp.
Homo Habilis
Homo Ergaster
Homo Erectus
Homo antecessor
H. Heidelbergensis
? H. Floresiensis ?
Neanderthal
H.sapiens

36. Ancestral Tree of Humans

37. Homo Sapiens Homo Erectus (Homo Heidelbergensis)
Homo Habilis (Homo Floresiensis) Paranthropus Boisei Neanderthal

38. Paranthropus robustus Homo neanderthalensis
Probable Brain Sizes
500 cm cm cm cm cm3
He thinks
He’s so
Smart!
Paranthropus robustus
1-2 million
years ago
Homo habilis
1-2 million
years ago
Homo erectus
40000 to 1 million
years ago.
Homo neanderthalensis
30000 to 1.8 million years ago
Homo sapiens

39. Geological Timetable: Extinctions
Era
From/to
events
periods
Ends with
Cenozoic
“Age of Mammals”
Now
Mammals
birds
Quaternary
Extinction?
65mya
Tertiary
Mesozoic
(middle animals)
“Age of Reptiles”
65 MYA
Dinosaurs
Early mammals Reptiles
Cretaceous
Extinction!
Jurassic
250 MYA
Triassic
Extinction.
Paleozoic
(ancient animals)
“Age of Invertebrates”
540 MYA
Early reptiles
Amphibians
Insects, mollusks
trilobites
Permian
Extinction!!
Carboniferous
Devonian
Silurian
Ordovician
Cambrian
Earlier Eras
“Precambrian”
4 BYA
bacteria, etc First Life,. Earth cools
Pre-cambrian
See previous slide 5 4 3 2 1

40. Assignment
Read through chapter 10 in your text book, and answer the questions on pages 325 to page 329.
There are 20 questions in all .
See blackboard for due date.

41. Answers to Questions Page 325
1. a) The matter that formed our planet came from a great cloud of dust and gas that orbited our sun after it first formed.
B) The earth formed about 4.6 billion years ago (but it took about a billion years for it to cool off and form oceans).
C) The moon may have formed when a large celestial body collided with Earth with such force that it broke off a piece of the planet. The debris from the impact condensed, eventually forming the moon

42. 2 A) The photo illustrates the presence of liquid water.
B) The photo illustrates lightning, a source of energy for the formation of life.
C) Other conditions not illustrated are:
Presence of elements necessary for life.
A long period of time.

43. 3. A) The elements most needed for life include carbon, hydrogen, oxygen, nitrogen and sulfur.
B) Scientists believe that these elements came from the atmosphere of earth.
C) It took a long time to form cells because the probability of them forming was low
D) Life appeared between 3.5 and 3.8 billion years ago.
E) The earliest forms of life resembled bacteria
(your textbook mentions cyanobacteria, but I think they more closely resembled archaebacteria)

44. 4 A) the slow process that brings about modification of living beings is evolution
B) Natural Selection gradually results in organisms better adapted to their environment.

45. 5 A) Cenozoic is the era we live in
B) The Mesozoic era is when the dinosaurs lived and became extinct
C) The “Precambrian” Era was the longest era
D) The Cenozoic era is when most of the mammals appeared.
E) The Paleozoic era ended with the largest mass extintion

46. 6. Event Era Period Appearance of our species Cenozoic Quaternary
Extinction of dinosaurs
Mesozoic
Cretaceous
Appearance of dinosaurs
Triassic
Extinction of 90% marine life
Paleozoic
Permian
Appearance of amphibians, insects
Devonian
Appearance of fish
Ordovician
Appearance of vertebrates
Appearance of soft invertebrates
Precambrian
First evidence of life
Precambrian*

47. 7. The 380 million year old fish lived in the Paleozoic era and the Devonian period.
8. Jurassic Park was an appropriate name for a movie about dinosaurs, because many types of dinosaur existed in the Jurassic period
I personally think a better name would have been Cretaceous Park, because the two “Star” dinosaurs (T-Rex and velociraptor) were more common in the Cretaceous Period.

48. 9. 10. A) The chimpanzee is our closest “cousin”
B) The main feature used to distinguish between humans and apes is bipedalism (the ability to walk upright)
10.
A) Three human genera are Australopithicus, Paranthropus, and Homo
B) the scientific name of humans is homo sapiens.a
C) Two other human species were Homo floresiensis, and Homo neanderthalensis..

49. 11. Adaptations include:
A) Bipedalism, allowed us to use our hands to carry things and use tools
B) Our brain allowed us to reason, become inventive, develop tools, and communicate using complex languages.
C) Our fine hair allowed us to keep cool
D) Our sweat glands also allowed us to cool off during hot African days.

50. 12. It is difficult to establish exactly how humans evolved because there is not as much fossil evidence as we would like.
13. Fossils are usually found in sedimentary rock.

51. 15. a) a body fossil is not shown
14.
Fossil
Type
Formation
Footprints
Trace
The traces left in soil hardened
Bones
Petrified
The bones hardened and mineralized
Trilobite
Cast
Impression of trilobyte filled in with minerals
15. a) a body fossil is not shown
b) A mammoth frozen in ice or an insect preserved in amber are examples of body fossils

52. 16 A. False a palaeontologist studies fossils
B. True there are petrified trees
C. False most fossils come from sedimentary rocks
D. False most organisms just decay
E. True some fossils show both bones and impressions
(like archaeopteryx, the first bird, on page 322)
F. False relative dating is less accurate
G. True The carbon 14 gradually disappears

53. 17.
The law of continuity says that all sedimentary rock in a single layer formed at the same time. The law of superposition says that the deeper a layer is, the older it is

54. 18
A) If you think a tree is older because it is larger, you are using relative dating
B) If you count the tree rings it is absolute dating

55. 19
A. Carbon-14 dating is based on the decay of radioactive isotopes (radiometric dating)
B. The older the fossil, the less radioactive carbon-14 it will have in it

56. 20.
A. The orange layer is the oldest, since by the law of superposition the oldest layer is the deepest
B. Species “B” probably appeared first, since its fossils appear in an older layer
C. Species “B” probably disappeared last, since its fossils are also found in a higher layer
D. Yes, they both existed during the time the middle layer was deposited.
E. Relative dating helps us establish the dates of the stratigraphic layers
F. Elements like uranium would be better than carbon 14 for determining the age of these fossils.