Geologic Change

1. Geologic Change Alexander Crumpton Fuqua

2. 8.E.2.1 Fossils

3. Paleontology • The science involved with the study of a past life. • The data used for this study of a past life are fossils

4. Fossils • Fossils are the preserved remains or traces of organisms that have been preserved by geologic processes. • Provide evidence of how life and the environment has changed • The processes we see today are similar to those in the past.

5. Uniformitarianism • The idea that the same geologic processes shaping the earth today have been at work throughout history. • Erosion • Deposition • Movement of Lithospheric Plates • Changes in atmosphere

6. Catastrophism • The principle that states that all geologic changes occur suddenly . • Through catastrophes such as: • Impact of an asteroid or comet • Earthquakes

7. 6 Types of Fossils • Mold Fossil • Cast Fossil • Petrified (Permineralized) Fossil • Preserved Fossil • Carbonized Fossil • Trace Fossil

8. Mold Fossil • Forms when sediments bury an organism and the sediments change into rock • The organism decays leaving a cavity in the shape of the organism

9. Cast Fossil • Forms when a mold is filled with sand or mud that hardens into the shape of the organism

10. Petrified Fossil • Also known as permineralized fossils • Forms when minerals soak into the buried remains, replacing the remains, and changing them into rock

11. Preserved Fossils • Forms when entire organisms or parts of organisms are prevented from decaying by being trapped in rock, ice, tar, or amber.

12. Carbonized Fossils • Forms when organisms or parts, like leaves, stems, flowers, fish, are pressed between layers of soft mud or clay that hardens squeezing almost all the decaying organism away leaving the carbon imprint in the rock.

13. Trace Fossil • Forms when the mud or sand hardens to stone where a footprint, trail, droppings, or burrow of an organism was left behind • Helps to give clues to an animals diet and lifestyle.

14. Geologic Time Scale • A record of the major events and the diversity of life forms in Earth’s history • At the end of each era, a mass extinction occurred, many kinds of organisms died out.

15. Divisions of Time • Eon: largest division of time • Containing two or more Era • Era: a defined period of time with a start event and an end event • Period: form a division which geologist use to divide earth’s history. • Epoch: a division of time that is longer than an age, but shorter than a period

16. Precambrian Era • First era of time • Bacteria and simple algae, leading to jellyfish and sea worms • Few fossils • Paleozoic Era • Early invertebrates, trilobites, leading to early vertebrate fish, arachnids, insects, first amphibians, reptiles become dominant by the end. • Early land plants, mosses, ferns, cone-bearing plants • Mesozoic Era • Reptiles were dominant animals, dinosaurs • Small mammals and birds appeared • Flowering plants and types of mammals increased • Dinosaurs became extinct at the end of this era • Cenozoic Era • New mammals appeared • Diversity of life increased

17. Relative age of rocks does not tell exact age • Can be determined using 2 different methods: • Ordering of Rock Layers • Index Fossils • Ordering of rock layers • The Law of Superposition • Each rock layer is older than the one above it. • Younger layers lie on top of older layers, unless disturbed. • Index Fossils • Used to find the relative age • To be considered an index fossil: • An organism must have lived for a short period of time in Earth’s history and must be widespread across the globe. • Trilobites

18. Trilobites • Hard shelled animals • 3 body sections • Lived in shallow seas • Became extinct about 245 million years ago.

19. Absolute Dating • Absolute dating is any method of measuring the age of an event or object in years. • Radiometric dating • Radioactive “Parent atoms” decay into “daughter atoms” at a predictable rate. • They become trapped in rock when it forms. • By measuring amount left after decay, scientist can predict how much time has passed. • Carbon-14 dating is most frequently used. • Half-life: the amount of time needed for half of a radioactive isotope to disappear.

20. 8.E.2.2 Artifacts of Geologic Change

21. Other artifacts scientist can use to determine geological history: • Ice cores • Cylinders of ice drilled out of glaciers and polar ice sheets • Help understand how the climate has changed over time • Record of atmosphere and compounds in the air where it formed. • Examining layers of sedimentary rock • Makes up about 75% of earths surface • Forms where sand, mud, or other sediments collect • Can be disturbed by igneous rock, which is formed from molten rock (magma), causing intrusions.

22. Geologic Column • An arrangement of rock layers in which the oldest rocks are at the bottom.

23. Disturbed Rocks • Folding: rock layers bend and buckle • Faulting: a break in the earths crust • Intrusion: molten rock that squeezes into existing rock. Always younger than the layer it cuts through. • Tilting: when internal forces in the earth slant the layers

24. Gaps in the Record • Unconformities: a break in the geologic record created when rock layers are eroded or when sediment is not deposited for a long time • Represent missing time that was not recorded.

25. 8.L.4.1 Evolution

26. Biological evolution: the change over time of living organisms • Acquire characteristics through adaptations • Change in structure, behavior, or physiology that helps an organism survive a particular environment • Homologous Structures: same structure, different function (wing of a bat and arm of a human) • Analogous Structures: same function, different structure (wing of a bird and wing of a butterfly) • Fossils can be compared to each other and living organisms to observe any changes over time • Transitional fossils

27. Extinction • It occurs when an environment changes and the organism does not have traits necessary to survive and reproduce. • Most species that have lived on earth are now extinct. • Extinction is apparent in the fossil record.

28. Biological Classification • System used to organize all life on Earth. • Used to: • Describe organisms • Examine the relationships between organisms • Also referred to as taxonomy (KPCOFGS)

29. Theory of Evolution • States that species change over time • Change in response to their environment • Charles Darwin is known as the “Father of Evolution” • Theory that all life is related from a common ancestor • As genetic mutations occur, the beneficial mutations are kept and passed on, because they aid in survival • The process known as natural selection • The beneficial mutation builds and creates an entirely different organism.

30. Charles Darwin Charles Darwin was a naturalist who sailed around the world from 1831 to 1836 to study biology and geology. With some of the information about plants and animals he observed on this trip in mind, he later published a book about the theory of evolution by natural selection.

31. Darwin’s Finches Here is an example of a Galapagos finch that Darwin researched that adapted their beaks to eat a type of food source common to the area.

32. Factors impacting survival of a species: • Phenotype • Body structure and characteristics • Can influence the ability to find, obtain, or utilize resources (Food, water, shelter, etc) and even reproduce • Genotype • The genetic code of an organism • Beneficial vs Harmful Mutations • Physical Conditions • If the environment changes, the organisms with favorable traits to survive, will reproduce and pass on those traits. • Those without the traits, most likely die or produce fewer offspring. • The greater the diversity of a species, the greater the chance for survival during environmental changes.

33. Geological Evolution: change in landforms over time. • Theory of Plate Tectonics • Movement of earth’s continental and oceanic plates • Caused mountains and trenches to form which continually shape the earth’s surface. • Movement of the plates causes changes in climate, geographic features, sea levels, and types of organisms in a location. • Pangaea • Theory of Continental Drift • Law of Superposition: • In any undisturbed sequence of rocks deposited in layers, the youngest layer is on top and the oldest on the bottom.