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Earth’s Historical Highlights

Earth’s Historical Highlights. Major stages in the history of Earth Major Extinctions. 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. The Eons of Time.

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Earth’s Historical Highlights

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  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. The Eons of Time Eons divided into Eras divided into Periods (what was going on) COMPLEX LIFE 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 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 ERAThe “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 (439-409 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

  16. 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.

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

  18. Mesozoic Earth

  19. 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

  20. 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

  21. Cenozoic Era: The age of Mammals Known for the success and diversification ofmammals

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

  23. 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

  24. Chapter 17: Human Evolution

  25. 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

  26. 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

  27. 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 1994. 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

  28. 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

  29. 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.

  30. 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

  31. 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.

  32. Some lesser-known and disputed hominid fossils • Homo Floresiensis? “hobbit”: a very small hominid fossil recently found in Malasia dating to about 13000 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

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

  34. Ancestral Tree of Humans

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

  36. Probable Brain Sizes 500 cm3 700 cm3 1000 cm3 1450 cm3 1400 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

  37. Geological Timetable: Extinctions 5 4 3 2 1

  38. 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.

  39. 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

  40. 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.

  41. 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)

  42. 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.

  43. 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

  44. 6.

  45. 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.

  46. 9. • 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..

  47. 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.

  48. 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.

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