Presentation on theme: "Earth’s Historical Highlights"— Presentation transcript:
1 Earth’s Historical Highlights Major stages in the history of EarthMajor Extinctions
2 The Beginning Earth is formed from dust and debris orbiting the sun A process named AccretionLike snowballing~4.6 BYA(billions of years ago)Then the crust formed
3 This whole time is simply called The Eons of TimeEons divided into Eras divided into Periods (what was going on)COMPLEXLIFEMillions of Years AgoPhanerozoicEonCenozoic eraQuaternary, TertiarayMammals200Mesozoic eraCretaceous, Jurassic, TriassicReptiles, birds400PaleozoicPermian, Carboniferous, DevonianFish, amphibians600Silurian, Ordovician, CambrianInvertebrates800ProterozoicSingle Cells & colonialNeoproterozicEdiacaran, Cryogenian, TonianStenian,Ectasian,Calymmian1000 MYA (1 BYA)Mesoproterozic1200Colonial Organisms?140016001800PaleoproterozoicStatherianOrosirianRhyacianSiderian2000 MYA (2 BYA)22002400Eukaryotes?2600Archean EonBacteria onlyNeoarchean(not yet divided into periods)2800Meoarchean3000 MYA (3 BYA)Paleoarchean3200EoarcheanBacteria?3400Hadean EonNo LifeEarly ImbrianBombardment ends3600Nectarian EraEarth cools, Oceans form3800Basin Group Eracometary bombardment!4000 MYA (4 BYA)Cryptic EraSun & Planets formMICROSCOPIC LIFEIn Your TextbookThis whole time is simply calledPrecambrianBACTERIAL LIFENO LIFEThis 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”NowMammalsbirdsQuaternary65myaTertiaryMesozoic(middle animals)“Age of Reptiles”65 MYADinosaursEarly mammals ReptilesCretaceousJurassic250 MYATriassicPaleozoic(ancient animals)“Age of Invertebrates”540 MYAEarly reptilesAmphibiansInsects, molluskstrilobitesPermianCarboniferousDevonianSilurianOrdovicianCambrianEarlier Eras“Precambrian”4 BYAbacteria, etc First Life,. Earth coolsPre-cambrianSee previous slide54321
5 ERAS (simplified)Cenozoic Era: Our era… lots of mammals, birds, flowering plantsMesozoic Era: Age of reptiles. Dinosaurs and other large reptiles, gymnosperm plantsPaleozoic 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 lifeThere was only one continent at the beginningRodinia (the mother continent)The land started off cold, but the seas warmed up quicklyLife proliferatesExtensive variety of sea lifeThe 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 beginningRodinia: the first supercontinent (the mother continent)Most life was aquatic (ocean life)Sponges (formless animals)Jellyfish (soft aquatic animalsTiny molluscs (snails, clams)Marine WormsTiny mollusc shells from Cambrian Period (early Paleozoic)
10 PALEOZOIC ERA: Part II The Ordovician Period The supercontinent began to break apartInto Gondwana ,Laurentia and BalticaAfrica, South AmericaAntarctica & IndiaNorth AmericaEuropeCommon 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 landMostly mosses and primitive fern ancestors.No really big trees yet
12 PALEOZOIC ERA: Part IV Devonian Period: (409-363 MYA) First amphibians appearedFirst insects appearedPlants became larger and more variedUnderwater, fish were becoming larger and more diverse
13 PALEOZOIC ERA: Part V The Carboniferous era (363-290 MYA) AKA: Mississippian/Pennsylvanian EraGreat 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.DimetrodonThe Permian period ended with the greatest of all mass extinctions.90% of aquatic life became extinct75% of terrestrial lifeThis also brought the paleozoic era to an end.
17 End of the PalaeozoicAlthough 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 animalsAKA the Dinosaurs’ eraAlbertosaurus
20 Periods of the Mesozoic Era Triassic Period:Dinosaurs appearedJurassic PeriodDinosaurs grew larger and more diverse. Small mammals and primitive birds may have developedCretaceous PeriodPangea broke up into the modern continentsThe 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 mammalsQuaternary Period: primates and hominids evolved
25 The Quaternary Period (Periods are smaller divisions of Eras) Known for global glaciationsIce agesModern man has been evolving forOver a million years (perhaps as much as three million years)But has been sedentary for only ~10000 yearscivilized
27 Hominid FossilsHumans 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 fromAbout 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 agoAustralopithicus africanus, Taller and heavier than “Lucy” lived in Africa between 2.3 and 3 million years agoParanthropus* robustus and Paranthropus* boisei “nutcracker man” both lived between 1 and 2 million years ago in AfricaAustralopithicusParanthropus* 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 AntecessorHomo 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
37 Homo Sapiens Homo Erectus (Homo Heidelbergensis) Homo Habilis (Homo Floresiensis) Paranthropus Boisei Neanderthal
38 Paranthropus robustus Homo neanderthalensis Probable Brain Sizes500 cm cm cm cm cm3He thinksHe’s soSmart!Paranthropus robustus1-2 millionyears agoHomo habilis1-2 millionyears agoHomo erectus40000 to 1 millionyears ago.Homo neanderthalensis30000 to 1.8 million years agoHomo sapiens
39 Geological Timetable: Extinctions EraFrom/toeventsperiodsEnds withCenozoic“Age of Mammals”NowMammalsbirdsQuaternaryExtinction?65myaTertiaryMesozoic(middle animals)“Age of Reptiles”65 MYADinosaursEarly mammals ReptilesCretaceousExtinction!Jurassic250 MYATriassicExtinction.Paleozoic(ancient animals)“Age of Invertebrates”540 MYAEarly reptilesAmphibiansInsects, molluskstrilobitesPermianExtinction!!CarboniferousDevonianSilurianOrdovicianCambrianEarlier Eras“Precambrian”4 BYAbacteria, etc First Life,. Earth coolsPre-cambrianSee previous slide54321
40 AssignmentRead 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 lowD) 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 extinctC) The “Precambrian” Era was the longest eraD) 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 dinosaursMesozoicCretaceousAppearance of dinosaursTriassicExtinction of 90% marine lifePaleozoicPermianAppearance of amphibians, insectsDevonianAppearance of fishOrdovicianAppearance of vertebratesAppearance of soft invertebratesPrecambrianFirst evidence of lifePrecambrian*
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 periodI 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 HomoB) the scientific name of humans is homo sapiens.aC) 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 toolsB) Our brain allowed us to reason, become inventive, develop tools, and communicate using complex languages.C) Our fine hair allowed us to keep coolD) 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.FossilTypeFormationFootprintsTraceThe traces left in soil hardenedBonesPetrifiedThe bones hardened and mineralizedTrilobiteCastImpression of trilobyte filled in with minerals15. a) a body fossil is not shownb) 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 treesC. False most fossils come from sedimentary rocksD. False most organisms just decayE. True some fossils show both bones and impressions(like archaeopteryx, the first bird, on page 322)F. False relative dating is less accurateG. 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 18A) If you think a tree is older because it is larger, you are using relative datingB) If you count the tree rings it is absolute dating
55 19A. 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 deepestB. Species “B” probably appeared first, since its fossils appear in an older layerC. Species “B” probably disappeared last, since its fossils are also found in a higher layerD. Yes, they both existed during the time the middle layer was deposited.E. Relative dating helps us establish the dates of the stratigraphic layersF. Elements like uranium would be better than carbon 14 for determining the age of these fossils.