Geologic History and Biological Evolution

1. Geologic History and Biological Evolution Fossils Fossils- preserved remains or traces of living things, found in sedimentary rock **For fossil to form we the organism NEEDS to have hard parts ex. Bone, shells, teeth, seeds woody stems 1.) The organism dies 2.) It is buried by sediment 3.) the sediment hardens into rock and preserves the shape of the organism 4.) Uplift, weathering and erosion expose the fossil **Many organisms that become fossils live in or near quiet water (swamps, lakes or shallow seas)

2. Geologic History and Biological Evolution Types of Fossils • Molds and Casts (most common) • Molds-hollow area in sediment in the shape of an organism, organism is buried then decays • Cast-solid copy of the shape of an organism, formed when water deposits minerals in a mold • BOTH can preserve fine details • Video clip of mold and cast formationMold Cast • Trace Fossils- provide evidence of the activities of ancient organisms, ex. Footprint, trails, burrows, coprolite, eggs and nests Burrows • Preserved Remains- • Sticky tar • Tree resin produces amber (hardened tree sap) which traps organisms • Freezing

3. Geologic History and Biological Evolution Fossils help explain Earth’s History • Show how life changed/evolved over time • Show how Earth’s surface has changed • Marine fossils found on the top of mountains • Show how climate has changed • Tropical coral fossils found in northern part of US • Show how appearance and activity of past life has changed • Teeth give clues to what animals ate • Bones give clues to how animals looked

4. Geologic History and Biological Evolution Relative Dating Relative Age-Age compared to the other things around it **Fossils are most often found in sedimentary rock Principle of Uniformitarianism- This geologic principle states the geological processes (Weathering, Erosion, Volcanism, Earthquakes, etc.) that occur today also occurred in the past in the same ways. ***Think about people who wear a uniform – nurses, students, police officers  they all look the SAME • The present is the key to the past Law of superposition -geologic principle that states that in undisturbed horizontal layers of sedimentary rock, each layer is older than the layer above it and younger than the layer below it **More simply—the oldest layer is on the bottom and the youngest is on the top Index Fossils- layers with matching index fossils are the same age To be an index fossil, the species must have 1.) Be geographically widespread 2.) Lived for a short period of geologic time Match the rock layers in locations 2, 3, and 4 with first area shown. Which fossils can be used as index fossils?

5. Geologic History and Biological Evolution Relative Dating (cont.) Principle of Original Horizontality- States that sediments are deposited in flat lying or horizontal layers that are parallel to the surface on which they were deposited. • Sedimentary rocks NOT in horizontal layers have been altered after they were deposited. Anything that disturbs sedimentary rock layers, has to be YOUNGER than the layers if affects Disturbances include: • Faulting • Folding • Tilting • Igneous Intrusion or Extrusion • This means that if rocks are tilted or folded, they have been deformed after deposition. Principle of Cross Cutting Relations- States that if something (such as faults, cracks, veins, or intrusions - magma cooling underground, extrusions - lava cooling on the surface) cuts through rock layers, the rock layers themselves must be older than the thing cutting through them. Extrusion-lava that hardens on Earth’s surface and forms igneous rock (rock that is formed from magma) **An Extrusion is always younger than the rock around it and below it Intrusion-magma that pushes into rock layers and cools as igneous rock below Earth’s surface **An Intrusion is always younger than the rocks around or beneath it

6. Geologic History and Biological Evolution Fault- a break in Earth’s crust due to forces inside Earth which causes movement of the rock on opposite sides (line the arrow is pointing to is a fault) **A fault is ALWAYS younger than the rock that it cuts through Folding: • Occurs when sedimentary rock layers are bent upwards or downwards from their original horizontal position • Folding is YOUNGER than the youngest rock affected • Sometimes forces inside Earth fold layers so much that the layers are over turned • The youngest layers might end up on the bottom

7. Geologic History and Biological Evolution Extrusion-lava that hardens on Earth’s surface and forms igneous rock (rock that is formed from magma) **An Extrusion is always younger than the rock around itandbelow it Intrusion-magma that pushes into rock layers and cools as igneous rock below Earth’s surface **An Intrusion is always younger than the rocks around it (above, below and to the sides) Contact Metamorphism: Occurs when magma (an intrusion or extrusion) “scars” and heats up existing rock layers. This alters the rock into metamorphic rock. **Represented by hash marks around intrusion/extrusion

8. Geologic History and Biological Evolution Put the Principles into Practice When I make a PB & J sandwich, I can say: • The way you make a PB & J sandwich is the same now as your parents made it for you (Principle of Uniformatarianism) • The bread had to be flat for me to spread the peanut butter on it (Principle of Original Horizontality) • One piece of bread was there for me to spread the PB on (Principle of Superposition) • The bread is older than the PB bc it was there first • If I slice the sandwich, all those layers (PB, J, and bread—both top and bottom) had to be there before I cut into the sandwich (Principle of Cross Cutting Relations)

9. Geologic History and Biological Evolution Unconformity-buried erosional surface, represents a gap in time in Earth’s history **It is represented by a wavy line • When rock layers erode away, an older rock surface may exposed, it may erode itself then deposition begins again building new rock layers **Due to erosion, most of the geologic rock layers and evidence in them has been lost

10. Geologic History and Biological Evolution Lets see if we can figure out the sequence of events: List in order the layers from oldest to youngest 1.) 2.) 3.) 4.) 5.) Now try the examples in your packet. If you think you have mastered it, try the one on the following slide 

11. Geologic History and Biological Evolution Put the layers in order from oldest to youngest

12. Geologic History and Biological Evolution Absolute Dating Absolute Age-number of years that have passed since the rock was formed Isotope-Atoms of the same element can have different numbers of neutrons; the different possible versions of each element are called isotopes Example: Carbon-12 Carbon-14 The number after carbon indicates the mass number (protons + neutrons) for that isotope Radioactive Dating- Radioactive Decay-the process in which the nuclei of radioactive elements break down, releasing fast moving particles and energy • During radioactive decay, the atoms of one element (isotope) break down (change) to form atoms of another element (isotope) • Radioactive elements occur naturally in igneous rock • Scientists use the decay rate to determine the rocks age

13. Geologic History and Biological Evolution • In the table below, note that the number is the mass number (the total number of protons plus neutrons). • The mass number may vary for an element, because of a differing number of neutrons. Elements with various numbers of neutrons are called isotopes of that element. Parent Element- the original, unstable, radioactive element, decreases through out process Daughter Element- the resulting, stable, non radioactive product due to radioactive decay, increases through out process

14. Geologic History and Biological Evolution Half Life-the time it takes for half of the radioactive atom to decay to the daughter element **The half life for the radioactive element never changes no matter how much the starting mass of the substance is or how much is left Determining the Absolute Age of Rocks 1.) Scientists determine the amount of radioactive material in rock 2.) Compare the radioactive amount to the stable amount **Potassium-40 is useful in dating ancient rocks because of its long half life **Carbon-14 is used to date fossils because all living things contain carbon. --cannot be used to date fossils older than 57, 000 years or more than 10 half lives, because the amount of carbon left is too small to measure

15. Geologic History and Biological Evolution • Draw a circle, shade the circle and fill in the chart according to how it changes as each half life passes

16. Geologic History and Biological Evolution Lets try some practice problems. 1.) You have a fossil that contains Carbon-14, you know that the total mass of that sample was 40mg. You have determined that there is 30 mg of Nitrogen-14 in the fossil. Answer the following: a.) How many half life’s have passed? b.) This fossil was formed how many years ago? c.) What percentage of parent element is present? d.) What percentage of daughter element is present? 2.) You have a sample of rock with an unknown radioactive material in it, but you have information stating that it was formed 3.9 billion years ago. You know that the parent element is 7.5mg and the daughter element is 52.5mg. Answer the following: a.) What % is the parent element b.) What % is the daughter element c.) How many half life’s have passed d.) What is the parent element, what is the daughter element?

17. Geologic History and Biological Evolution The Geologic Time Scale Geologic Time Scale- Record of the geologic events and evolution/extinction of life forms as shown in the fossil record **Remember life started out very simple and evolved to much more complex • Because the time span of Earth’s history are so great, geologists use the geologic time scale to show Earth’s history • They use evidence from • Rock layers (relative dating) • Index fossils • Radioactive dating • Everyday divisions of time (century, decade, year, month, week, day) are not helpful due to the age of the Earth • Major changes in life forms are used to mark where one unit of geologic time starts and another begins • Precambrian = 88% of Earth’s history • Era-three long units of time that divide time after Precambrian to present (Paleozoic- Age of Fish/Amphibians, Mesozoic-age of reptiles, Cenozoic—age of mammals) • Period-Subdivisions of Eras • Names of many geologic periods come from places where geologists first described the rocks and fossils for that period

18. Geologic History and Biological Evolution Earth's History in a Day The table shows the times at which some major events would take place. Visualize each event on the clock diagram.

19. Geologic History and Biological Evolution Early Earth Age of Earth • Scientists dated the oldest rock to 4 billion years old, but think the Earth formed before that • Moon formation- young Earth collided with another object, due to this Earth and moon must be similar in age • Rocks from moon have been radioactively dated at 4.6 billion years old via carbon dating Earth takes shape • Scientists think that Earth began as a ball of dust, rock and ice in space. • Gravity pulled this “junk” together • As the Earth grew larger, its gravity increased and it pulled in more and more “junk” • Due to the collision of this material, energy was released which raised Earth’s temp until it was VERY HOT—to the point where it melted • Dense materials sank toward the bottom (hence the dense iron core), less dense, molten material hardened forming crust and mantle

20. Geologic History and Biological Evolution Early Earth This artist’s illustration shows Earth shortly after the moon formed. Earth was hot and volcanic, and contained no liquid water. The moon was much closer to Earth than it is today. Over time, Earth’s surface began to cool, forming solid land.

21. Geologic History and Biological Evolution The Atmosphere: • First atmosphere composed of light gases- hydrogen and helium • Solar wind (strong bursts of particles released from the sun) blew away first atmosphere because gravity was not strong enough to hold on to it. • Second atmosphere-CO2, H2O and N added due to volcanic explosions and comets colliding with Earth • Comet- a ball of dust, gas, and ice that orbits the sun Development of the Atmosphere The illustration shows the difference between Earth’s first and second atmospheres. What is the missing information for each atmosphere? The Oceans: • At first = no oceans, Earth was too hot • All H2O was vapor • As Earth cooled, water vapor condensed to form rain, which accumulated to form oceans which absorbed much of the CO2 from the atmosphere The continents: • Early Precambrian- Earth’s rock cools and hardens • 500 million years later-continents formed • Over billions of years, Earth’s landmasses have repeatedly formed, broken apart and crashed together again

22. Geologic History and Biological Evolution Early Organisms • When or where life began is unknown for sure • Single celled organisms is rock that was formed 3.5 billion years ago • Other life forms arose from these single celled organisms • 2.5 billion years many organisms started producing food via photosynthesis which resulted in an increase of O in the atmosphere • Some of this O changed into O3 which is ozone • Ozone layer blocks UV rays from sun allowing organisms to thrive on land

23. Geologic History and Biological Evolution Precambrian Time (not an era) 4.6 billion years ago – 542 million years ago • Formation of earth 4.6 billion years ago • 4 billion years ago—oceans form, they cover earth • First sedimentary rocks form 3.8 billion years ago • Single celled organisms evolve to multi-celled near the end of the Precambrian Three Eras of Geologic Time (oldest to now) 1.) Paleozoic (542-251 mya) 2.) Mesozoic (251-66 mya) 3.) Cenozoic (66mya to present)

24. A trip through Geologic Time Paleozoic (542-251 mya) • 542-444 mya Age of Invertebrates (Cambrian and Ordovician Period) • First organisms with shells (beginning) • Trilobites dominate • First fishes (end) • 444-359 mya “Age of Fishes” (Silurian and Devonian Period) • First land plants (beginning) • Fishes dominate • First insect fossils (end) • 359-251 mya “Age of Amphbians (Carboniferous and Permian Period) • Largest amphbians abundant, coal swamps (beginning) • First reptiles • Extinction of trilobites, many other marine animals (end) • The Paleozoic Era ends with a mass extinction • 90% of ocean species and 70% of land species died out • Scientists not sure what caused extinction • Asteroid struck Earth—creating huge dust clouds • Volcanic eruptions released CO2 and S—temperatures rise • CO2 in oceans increase and O declines • ALL may have contributed

25. Geologic History and Biological Evolution Mesozoic Era (251-66 mya)AGE OF THE REPTILES • 251-200 mya (Triassic Period) • Dinosaurs dominate • 200-146 mya (Jurassic Period) • First birds • 146-66 mya (Cretaceous Period) • First flowering plants The Mesozoic Era ends with a mass extinction • Wipes out more than half of all plant and animal groups

26. A trip through Geologic Time Cenozoic Era (66 mya to present)AGE OF THE MAMMALS • 66-23 mya (Paleogene Period) • Modern groups of mammals appear, grasses first spread widely • 23–1.8 mya (Neogene Period) • Large carnivorous and grazing mammals • 1.8 mya to present (Quaternary Period) • Humans develop

27. Geologic History and Biological Evolution What evidence is there for the evolution of organisms in the Geologic Time Scale? First…..what is evolution? Evolution- Change over time Here is something familiar to us…..something that we have watched evolve…. What about video game consoles? • How are PSP and WiiU related? • How do I know that the Magnavox Odyssey ever existed?

28. Geologic History and Biological Evolution How do these examples relate to evolution of life on Earth? In your notebook, write down each term and compare it to our previous examples—cell phones OR the video game consoles • Comparative Anatomy • Embryology and development • Fossil Record • DNA Comparisons

29. Geologic History and Biological Evolution A real-life example of evolution…. Galapagos Islands The Galapagos Islands are a chain of islands in the Pacific Ocean, west of South America • At some point in history, a group of finches arrived on these islands from the mainland of South America. • Initially, there was just one species of finch. All of the birds had the same features. • As the finches traveled from island to island, they discovered that there was a variety of food choices available: fruit, insects, cactus and seeds. • Make a hypothesis as to how these finches may have changes as they ate different types of foods over the years.

30. Geologic History and Biological Evolution • As the groups of finches changed their diet, different beak shapes became more or less common. • For example, in groups that ate seeds, birds with thick, strong beaks did very well because they could break the seeds open. • Those with small, skinny beaks could not and did not survive. • The initial type of finch that arrived on the Galapagos Islands evolved into several different species. **Despite the differences in the warbler finch and the large ground finch, they evolved from the same finch that first came over from South America.

31. Geologic History and Biological Evolution Evidence of Evolution 1.) Fossil Record- all of the information that paleontologists have gathered about past life provides evidence about: A.) The Earth itself • Conditions of past environments • How the Earth’s surface has changed • Fossils can tell how much water in an area and what type of water is in an area (bay, ocean bottom, swamp) • Fossils can indicate what past climate was like • ex. Coal found in Antarctic • coal only forms from plants that grow in warm, swampy regions • this shows that the climate of Antarctica used to be warmer than it is today B.) Life on Earth • What life existed/dominated • The biodiversity on Earth • How life has changed over time • older rocks contain fossils of simpler organisms, younger rocks contain fossils of both simple and more complex organisms • the fossil record shows how organisms have EVOLVED and become EXTINCT

32. Geologic History and Biological Evolution Fossil Record (cont.) -Rock Strata • As we learned earlier in this unit, we can use a fossil's location in rock to try to trace the history of living things in a given area. • Layers of rock are called rock strata. • The further down in the Earth a fossil is, the older it is. -The Fossil Record • Since fossils show organisms in a sequential order, Youngest they provide evidence of the evolutionary changes of specific organisms. Oldest

33. Geologic History and Biological Evolution Fossil Record (cont.) Now we will look at a specific case--- The evolution of the modern horse

34. Geologic History and Biological Evolution Evidence of Evolution 2. Comparative Anatomy • Studying the similarities between different plants and animals reveal/show one specie's body parts can resemble another specie's body parts. Even though they live in vastly different environments, whales and hummingbirds share remarkably similar bone structures. These similarities provide evidence for evolution

35. Geologic History and Biological Evolution Anatomy (cont.) • Humans, dogs, birds and whales all have the same skeletal (bone) structure in their forearms. How do you think these similarities occurred?

36. Geologic History and Biological Evolution Anatomy (cont.) Two possibilities: 1.) Humans, dogs, birds and whales all independently evolved to have the same forelimb skeletal structure. 2.) Humans, dog, birds and whales have a common ancestor and each slowly evolved to have slightly different structures over time. ***The second option is the least complicated and, therefore, the most likely. Homologous Structures--structures that are anatomically similar, but could have different functions

37. Geologic History and Biological Evolution What similarities can you see between the limbs of a bat and a mouse? Although they are completely different animals, the anatomical homologies of bats and mice indicate tha they evolved from the same ancestor.

38. Geologic History and Biological Evolution Anatomy (cont.) • Vestigial Structures-a structure of an organism that has no apparent purpose • Vestigial structures provide clues about the evolution of the organism. Example: • The tailbone is a vestigial structure in humans. • We do not have a tail but we still have the bone to which a tail would be attached. • The underside of this boa constrictor shows tiny limbs that used to be legs. What does this tell us about the evolution of the boa?

39. Geologic History and Biological Evolution Evidence of Evolution 3. Embryology Embryo- early stage of development in a multi-cellular organism, (weeks 5-11 in humans) • Some homologies appear in the embryo but disappear before the organism is born. Studying the development of organisms provides evidence for evolution. • What do you think the gill slits tell us about the evolution of humans?

40. Geologic History and Biological Evolution • Ernst Haeckle studied the embryos of different vertebrates (animals with a backbone). • As embryos, these species shared similar features despite being incredibly different once fully grown! • What does this tell us about the evolution of these animals?