Presentation on theme: "Earths Historical Highlights Major stages in the history of Earth Major Extinctions."— Presentation transcript:
Earths 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 Millions of Years Ago Phanerozoic Eon Cenozoic eraQuaternary, TertiarayMammals 200Mesozoic eraCretaceous, Jurassic, TriassicReptiles, birds 400PaleozoicPermian, Carboniferous, DevonianFish, amphibians 600Silurian, Ordovician, CambrianInvertebrates 800 Proterozoic Eon Single Cells & colonial NeoproterozicEdiacaran, Cryogenian, Tonian Stenian, Ectasian, Calymmian 1000 MYA (1 BYA)Mesoproterozic 1200Colonial Organisms? PaleoproterozoicStatherian Orosirian Rhyacian Siderian 2000 MYA (2 BYA) Eukaryotes? 2600 Archean Eon Bacteria only Neoarchean(not yet divided into periods) 2800Meoarchean 3000 MYA (3 BYA)Paleoarchean 3200EoarcheanBacteria? 3400 Hadean Eon No Life Early ImbrianBombardment ends 3600Nectarian EraEarth cools, Oceans form 3800Basin Group Eracometary bombardment! 4000 MYA (4 BYA)Cryptic EraSun & Planets form Eons divided into Eras divided into Periods (what was going on) This scale of years is approximate, and may vary from other sources by a million years or so NO LIFE BACTERIAL LIFE COMPLEX LIFE In Your Textbook This whole time is simply called Precambrian MICROSCOPIC LIFE
Geological Timetable EraFrom/toeventsperiodsEnds 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 250 MYA 540 MYA Early reptiles Amphibians Insects, mollusks trilobites Permian Carboniferous Devonian Silurian Ordovician Cambrian Earlier Eras Precambrian 540 MYA 4 BYA bacteria, etc First Life,. Earth cools Pre-cambrian See previous slide
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
The Major Eras Life begins ~3.8bya Beginning of Precambrian Era –Bacteria and prokaryotes appear
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
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 earths oceans– sponges, molluscs, trilobites, worms etc. PALEOZOIC ERA The age of invertebrates Predominant life forms were invertebrates (no backbones) The Paleozoic era is divided into six periods
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)
PALEOZOIC ERA: Part II The Ordovician Period The supercontinent began to break apart –Into Gondwana,Laurentia and Baltica Africa, South America Antarctica & India North AmericaEurope Common life forms included: Trilobites (ancient arthropods) Jawless Fish (eels) Cartilage Fish (ancestors of sharks) Plants and animals began to colonize the land
Silurian Period ( MYA): Plants spread across the land –Mostly mosses and primitive fern ancestors. –No really big trees yet PALEOZOIC ERA: Part III
PALEOZOIC ERA: Part IV Devonian Period: ( MYA) –First amphibians appeared –First insects appeared –Plants became larger and more varied Underwater, fish were becoming larger and more diverse
PALEOZOIC ERA: Part V The Carboniferous era ( 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.
PALEOZOIC ERA: Part VI 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. Permian Period. ( 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 Palaeozoic Earth
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.
The Mesozoic Era: Age of Reptiles Meso/middle + zoic/animal = middle animals AKA the Dinosaurs era Albertosaurus
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
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 5 th mass extinction
Cenozoic Era: The age of Mammals Known for the success and diversificati on of mammals
Periods of the Cenozoic Era Tertiary period: there were many large and unusual mammals Quaternary Period: primates and hominids evolved
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
Chapter 17: Human Evolution
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
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 dont need to copy or memorize it
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
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 * These two were formerly placed in genus Australopithicus Australopithicus Paranthropus
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.
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
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.
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
Hominids (Human Ancestors) Ardipithicus sp. Australopithicus sp. Paranthropus sp. Homo Habilis Homo Ergaster Homo Erectus H. Heidelbergensis Homo antecessor Neanderthal ? H. Floresiensis ? H.sapiens 1 million Years ago 2 million Years ago 3 million Years ago 4 million Years ago Now | Ardi Lucy Nutcracker man
Ancestral Tree of Humans
Homo Sapiens Homo Erectus (Homo Heidelbergensis) Homo Habilis (Homo Floresiensis) Paranthropus Boisei Neanderthal
Probable Brain Sizes 500 cm cm cm cm cm 3 He thinks Hes so Smart! Homo neanderthalensis to 1.8 million years ago Homo sapiensHomo erectus to 1 million years ago. Homo habilis 1-2 million years ago Paranthropus robustus 1-2 million years ago
Geological Timetable: Extinctions EraFrom/toeventsperiodsEnds with Cenozoic Age of Mammals Now Mammals birds QuaternaryExtinction ? 65mya Tertiary Mesozoic ( middle animals ) Age of Reptiles 65 MYA Dinosaurs Early mammals Reptiles CretaceousExtinction! Jurassic 250 MYA Triassic Extinction. Paleozoic ( ancient animals ) Age of Invertebrates 250 MYA 540 MYA Early reptiles Amphibians Insects, mollusks trilobites PermianExtinction!! Carboniferous Devonian Extinction. Silurian Ordovician Extinction. Cambrian Earlier Eras Precambrian 540 MYA 4 BYA bacteria, etc First Life,. Earth cools Pre-cambrian See previous slide
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.
Answers to Questions Page 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
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.
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)
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.
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
6. EventEraPeriod Appearance of our speciesCenozoicQuaternary Extinction of dinosaursMesozoicCretaceous Appearance of dinosaursMesozoicTriassic Extinction of 90% marine lifePaleozoicPermian Appearance of amphibians, insectsPaleozoicDevonian Appearance of fishPaleozoicOrdovician Appearance of vertebratesPaleozoicOrdovician Appearance of soft invertebratesPrecambrian First evidence of lifePrecambrian*
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.
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..
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.
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.
14. FossilTypeFormation FootprintsTrace The traces left in soil hardened BonesPetrified The bones hardened and mineralized TrilobiteCast 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
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
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
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
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
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.