Notes on Life & Geologic Time Name:

Transcription

1 Notes on Life & Geologic Time Name: S.W.B.A.T Explain how time can be divided into units Relate changes of Earth s to divisions on the geologic time scale Describe how plate tectonics affects Geologic Time Trilobites - segmented animals that went extinct Good index because they lived over vast areas during time periods Geologic Time Scale divisions based mostly on events in Earth s history rocks on Earth contain no fossils When no life is evident in the fossil record other such as mountain-building is used to mark time Four major subdivisions from the time periods to the are - eons, eras, periods and epochs Eons - include the and the Phanerozoic Precambrian geologic time period (3.9 billion years!) that shows no fossil life at simple marine life-forms show in the rock record Towards the end of the eon more life evolved Phanerozoic shortest eon with an abundance of that shows more complex life about 544 million years ago This was also known as the Cambrian when more complicated marine organisms hard parts

2 Eras - marked by major changes in worldwide life (usually by mass ) Eras include the Paleozoic or ancient ; Mesozoic middle & the Cenozoic Periods - describe in more the types of life forms existing worldwide Epochs - describe (or more local) life forms in smaller than periods Organic Evolution Species - a group of organisms that only within that group Organic Evolution the fossil record shows that species over time Almost all species clearly show change over time or of years Natural Selection - traits within a species allow it to to changes in the environment Charles Darwin first proposed natural or survival of the fittest with If a species is unable to adapt to its it will die out and not pass on traits New species arise if enough traits are passed on where the species can no longer breed with the new species Artificial selection - selection of desired traits in animals & plants Over this has led to many breeds of animals (like & cats) and different plants

3 Trilobites variety of species that lived for 200 million years in oceans Fossils show many that allowed the trilobites to survive than the dinosaurs Pangaea all of Earth s were joined together in one huge landmass finally died out when Pangaea formed about million years ago The of shallow oceans wiped out the Trilobite Class Activity

4 Notes on Life & Geologic Time Earth/Space S.W.B.A.T Explain how geologic time can be divided into units Relate changes of Earth s organisms to divisions on the geologic time scale Describe how plate tectonics affects species Geologic Time Trilobites - segmented marine animals that went extinct Good index fossils because they lived over vast areas during specific time periods Geologic Time Scale divisions based mostly on extinction events in Earth s history Oldest rocks on Earth contain no fossils When no life is evident in the fossil record other evidence such as mountain-building is used to mark geologic time Four major subdivisions from the longest time periods to the shortest are - eons, eras, periods and epochs Eons - include the Precambrian and the Phanerozoic Precambrian longest geologic time period (3.9 billion years!) that shows no fossil life at first Gradually simple marine life-forms show in the rock record Towards the end of the eon more complex life evolved Phanerozoic shortest eon with an abundance of fossils that shows more complex life starting about 544 million years ago This was also known as the Cambrian Explosion when more complicated marine organisms evolved hard parts

5 Eras - marked by major changes in worldwide life (usually by mass extinctions) Eras include the Paleozoic or ancient life ; Mesozoic middle & the Cenozoic recent Periods - describe in more detail the types of life forms existing worldwide Epochs - describe regional life forms in smaller divisions than periods Organic Evolution Species - a group of organisms that only reproduce within that group Organic Evolution the fossil record shows that species change over time Almost all species clearly show change over geologic time or millions of years Natural Selection - traits within a species allow it to adapt to changes in the environment Charles Darwin first proposed natural selection or survival of the fittest with species If a species is unable to adapt to its environment it will die out and not pass on traits New species arise if enough different traits are passed on where the original species can no longer breed with the new species Artificial selection - human selection of desired traits in animals & plants Over time this has led to many breeds of animals (like dogs & cats) and different plants

6 Trilobites variety of marine species that lived for 200 million years in shallow oceans Fossils show many adaptations that allowed the trilobites to survive longer than the dinosaurs Pangaea all of Earth s continents were joined together in one huge landmass Trilobites finally died out when Pangaea formed about 250 million years ago The disappearance of shallow oceans wiped out the Trilobite habitat Class Activity According to Darwin s theory of natural selection, which animal species would more likely survive in a polar climate Cold-blooded animals with skin covered by scales or Warm-blooded animals with fur (explain)