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Geology - Part 3
- 1. Geology - Part 3 Fossils & The Geologic Column
- 2. What do They Study? • Archeologists – study artifacts (evidence of human life on Earth) • Paleontologists – study fossils (preserved remains of plants/animals) • Geologists – study rocks (the crust of Earth’s surface)
- 3. Fossils • Evidence of organisms that once lived on Earth • Most are found in sedimentary rock layers • Very small percentage of living things become fossils
- 4. Fossilization • For a fossil to be discovered, a deceased organism must be: – covered quickly to prevent decay or physical destruction – fossilized (usually by mineralization; requires water) – preserved from further potential destruction • erosion, rock deformation, etc. – unburied by paleontologists
- 5. Types of Fossils • Original Remains (True Form Fossils) – Preserved in amber, tar or ice • Petrified Fossils – Organic materials of dead organism are replaced with minerals deposited out of water & turned to stone • Carbon Films & Impressions – Liquids/gasses from organisms leave a "picture" or indentation • Trace Fossils – preserved evidence of the activities of deceased organisms (footprints, burrows, nests, etc.) • Molds & Casts – Under water, as sedimentary rock forms around dead organism, a mold is made. Later, the space left from the decayed organism is filled with sediment, forming a cast.
- 6. Original Remains (True Form Fossils) – Complete organisms preserved in amber (solidified resin), tar or ice • Organisms must be preserved quickly to prevent: • decomposition • scavengers • crushing/deformation
- 7. Petrifaction (mineralization) • remains are exposed to water containing large amounts of minerals • Over time, organic materials are replaced by minerals • Most fossils are a jumbled mess of petrified bones which paleontologists piece together.
- 8. Carbon Films & Impressions • Impression: • Plant/animal is buried in sediment and liquids/gases are forced out • Carbon film: • Thin, filmy, carbon residue leaves a “picture” of the creature
- 9. Trace Fossils • preserved evidence of the activities of deceased organisms (footprints, burrows, nests, etc.)
- 10. Mold & Cast Fossils • Organic remains become encased in sedimentary rock • Weathering disintegrates remains; hollow mold is formed • Other sediments seep into the rock and fill the space, forming a cast of the original organism
- 11. The Fossil Record • 95% of all discovered fossils are marine invertebrates, mostly shellfish • 4.75% are algae and plants • 0.2375% are non-marine invertebrates and insects • 0.0125% are vertebrates (fish, birds, mammals) • only 0.0025% of all unearthed vertebrate fossils consist of more than a single bone
- 12. Geologic Time • Assumes sedimentation occurs evenly and slowly over millions of years • Large gaps remain in the fossil record – they may be still hidden, have been destroyed, or never existed
- 13. Fossil Sorting • Fossil sorting is thought to represent the history of life on earth. • Fossils in the lowest rock layers are believed to have lived before those in upper layers. • The first appearance of a fossil could indicate when it first evolved. • The last appearance of a fossil is believed to be the time it went extinct.
- 14. • Cenozoic – "new life" • Mesozoic – "middle life" – dinosaurs • Paleozoic – "ancient life" Precambrian
- 15. Extinction • When a species cannot adapt to it’s environment (because of predation, loss of habitat or food supply, cataclysmic events, etc.) all of it’s kind may die. • The fossil record shows many examples of organisms we no longer see living on earth today • In evolutionary terms, extinction can help a more “fit” population flourish because it no longer competes for resources • Widespread extinction may indicate worldwide cataclysmic events such as a global flood or ice age
- 16. Out of Place Fossils • The Coelacanth was thought to have gone extinct with the dinosaurs 65 million years ago until it was discovered off the coast of Madagascar in 1938. • Many other “misplaced” fossils puzzle scientists since they don’t fit within the sorted geologic column (hoof prints with dinosaur bones, etc.) • Sometimes "older" fossils are found in rock layers above less primitive fossil forms. Coelacanth Living Fossil
- 17. Living Fossils • Crocodiles - dates back 230 million years • Army Ants - dates back 100 million years • Cockroaches - dates back 350 million years • Coelacanth - dates back 400 million years • Crinoid or Sea Lilly dates back 150 million years • Cycads dates back 240 million years • Dragonfly dates back 230 million years • Ginkgo dates back 270 million years • Horseshoe Crab - dates back 300 million years • Nautilus - dates back 500 million years • Neopilina molluscs - dates back 400 million years • Salamanders dates back 150 million years • Sturgeon dates back 250 million years • Tuatara dates back 200 million years. • Velvet Worm dates back 500 million years • Wollemi Pine - dates back 150 million years
- 18. Trilobites • Large class of extinct, marine bottom- dwelling arthropods – (group includes insects, spiders and crustaceans like lobsters) – abundant in Cambrian era rock layers – now extinct • Possessed extremely sophisticated compound eyes and vision
- 19. Puzzling Fossil Facts • The fossils found in one layer of stratified rock can be considerably different than the fossils found in another section of the same stratified rock. • It is disputed how long it takes fossils to form. Depending upon the conditions in which it formed, there is evidence that it could be millions of years or less than 50 years. – burial in hot, silica-rich volcanic ash can produced rapid fossilization
- 20. The "Cambrian Explosion" • Evidence in the fossil record shows that all major phylla were established in the transition from Late Precambiran to Early Cambrian time • In the creationist model, these animals represent descendants of original created kinds that became extinct during the Flood of Genesis. • Gradual evolution struggles to account for the sudden appearance of so many types of life at one time. – "Punctuated Equilibrium" is one solution • It is puzzling why there are little to no "precursor" fossils to all these varieties of life.
- 22. Transitional Fossils • Intermediate fossils are few and far between (and some say non-existent). – Archaeopteryx and Tiktaalik are two impressive (and relatively recent) finds – All are "mosaics", lacking in-between features such as scaly feathers Archaeopteryx – Some modern-day mosaic species have - feathered bird with teeth similar characteristics • platypus and hoatzin chicks Tiktaalik - four-legged fish?
- 23. Fossil Dating Methods • Relative Age – Geologic time scale created with the belief that younger fossils are deposited on top of older fossils (referred to as "stratigraphy" and based on the "principle of superposition") • Absolute Age – Dendrochronology (using cross-dating of tree ring patterns of petrified wood buried along with other fossils to date the rock layer) – Radioisotope dating • Molecular Clocks – Genetic divergence used to "count backwards" • Known Age – There really is no way to “absolutely” know the exact age of a fossil • unless a written date is found on or near it or it is referred to in a historical document
- 24. Relative Dating • Gives approximate age relative to where it is found • Performed by estimating fossil age compared with that of surrounding fossils and rock layers • Drawbacks – provides no info about age in years – based on assumptions of worldwide, uniform sedimentation similar to rates we see now – large gaps in the geologic record leave room for much speculation
- 26. Index Fossils • Geologists use these common fossils to “date” rock layers • Paleontologists use age of rock layers to “date” these fossils • These are all marine fossils - found all over the world
- 29. Absolute dating • Offers a numeric age • Performed by radiometric dating or dendrochronology • Drawbacks – part of the fossil is destroyed during the test – large margin of error – Assumptions of test question validity of dates
- 30. Radiometric Dating Timeline first life dinosaurs © NASA origin of Earth first complex cells humans
Hinweis der Redaktion
- Why do you think very few fossils are found in igneous or metamorphic rock? Fossils are usually found in sedimentary rock. Since most sedimentary rock is laid down by water, it follows that most fossils were laid down by water as well. The vast majority of the fossil record is made up of clams and other hard-shelled creatures. Most of the remaining fossils are of either water-dwelling creatures or insects. Only a tiny, tiny fraction of the fossils we find are of plants, reptiles, birds, and mammals. Many of the fossils we find are of plants and animals which are still alive today. Some of the fossils we find are of plants and animals which are now extinct. The fossils found in one layer of stratified rock can be considerably different than the fossils found in another layer of the same stratified rock.
- Penguin fossil discovery off the coast of Peru.
- Honeypot ant in amber: organism inside has decayed, but no external scavengers or decomposers had the chance to do their work. Some resin or frozen samples have allowed scientists to extract DNA samples. Baby wooly mammoth found frozen alongside a river in Siberia (found by a reindeer herder). Wooly mammoth pelvis excavated from the La Brea Tar Pits , in urban Los Angeles. Tar seeps up from the ground and is often camophlaged with dust, leaves, or water. Animals, plants, and microbes trapped in the tar are preserved. As the bones of dead animals sink into the asphalt, it soaks into them, turning them a dark-brown or black color. Lighter fractions of petroleum evaporate from the asphalt, leaving a more solid substance, which holds the bones. Apart from the dramatic fossils of large mammals, the asphalt also preserves microfossils : wood and plant remnants, rodent bones, insects, mollusks, dust, seeds, leaves, and even pollen grains.
- The oldest fossils of a particular plant or animal are always fully-formed (not some simpler version), and look identical in all significant aspects to the same plant or animal living today (although many fossil types are extinct). The near-oldest rocks, so-called “Cambrian” rocks, contain many complex creatures, like Trilobites (now extinct). They are fully-formed, and there is not the slightest trace of a more primitive ancestor to be found in the older, “Pre-Cambrian” rocks. This period in earth history is called the “Cambrian Explosion” because of the vast number of new life forms that seem to appear from nowhere. What is true between the Pre-Cambrian and Cambrian ages is also true between every other age - no transitional forms are found! The most frequently cited “intermediate form”, the reptile/bird “Archaeopteryx” is really a bird that has some reptilian features (like teeth). It has a “mosaic” of traits (some bird, some reptile), but each trait is fully-formed (including the feathers). There are animals alive today that are mosaics (e.g. the duckbill platypus and Haotzin chicks). A true reptile/bird intermediate would show reptilian scales “half-way” transformed into feathers. Because the fossil record show abrupt appearance and “stasis” (no change), the evolutionary theory of “punctuated equilibrium” was developed by Gould and Eldredge, which basically says we don’t see evolution in the fossil record because it happens fast in small isolated groups. It is an argument from lack of evidence.
- Coelacanth fossils are found in marine deposits below dinosaurs and in other marine layers that date about the same age as dinosaurs.9 It was once thought the coelacanth became extinct about 70 million years ago because their fossils are not found in any deposits higher than this. However, in 1938 living populations were found in the Indian Ocean.10 It appears that coelacanths were buried with other sea creatures during the Flood—as we would expect. The example of the coelacanth shows that animals are not necessarily buried in the same place as other animals from different environments. We don’t find human bones buried with coelacanths, either, but we live together today, and people are enjoying them for dinner in some parts of the world. Frequently, fossils are not vertically sequenced in the assumed evolutionary order. For example, in Uzbekistan, 86 consecutive hoof prints of horses were found in rocks dating back to the dinosaurs. Hoof prints of some other animal are alongside 1,000 dinosaur footprints in Virginia. A leading authority on the Grand Canyon published photographs of horse-like hoof prints visible in rocks that, according to the theory of evolution, predate hoofed animals by more than 100 million years. Dinosaur and humanlike footprints were found together in Turkmenistan and Arizona. Sometimes, land animals, flying animals, and marine animals are fossilized side-by-side in the same rock. Dinosaur, whale, elephant, horse, and other fossils, plus crude human tools, have reportedly been found in phosphate beds in South Carolina. Coal beds contain round, black lumps called coal balls, some of which contain flowering plants that allegedly evolved 100 million years after the coal bed was formed. In the Grand Canyon, in Venezuela, in Kashmir, and in Guyana, spores of ferns and pollen from flowering plants are found in Cambrian rocks— rocks supposedly deposited before flowering plants evolved. Pollen has also been found in Precambrian rocks deposited before life allegedly evolved.
- The trilobite eye is the “oldest eye of which we have record” (Sinclair, 1985, p. 9). Trilobites lived, by evolutionist reckoning, over 500 million years ago. Duke-Elder wrote a half century ago that a major problem for vision evolution is that “among the earliest fossils known to man” the Trilobites, Arthropods which crept over the sea-bed… both median ocelli [simple eye] and lateral compound eyes were present which have reached a high stage of complexity ” (1958, pp. 156-157). Trilobite scientists now conclude that trilobites “possessed the most sophisticated eye lenses ever produced,” and their vision may actually have “been superior to current living animals” (Shawver, 1974, p. 72). Based on careful examination of fossils, researchers have concluded that trilobites could see exceptionally well, even though they often lived in the deep (thus very dark) sea bottom. One reason why is that their eye lenses were designed specifically to function in low-light, watery environments. A compound eye is constructed from a large array of separate eye optical elements called ommatidia. Each eye component (ommatidium) was pointed in a different direction, allowing the trilobite to simultaneously see in front, on each side, and behind it, giving it a panoramic view of the world (Fortey, 2004, p. 449). A network of photoreceptors and neurons then translated the many optical images picked up by the compound eye into a single composite picture. Evidence of the effectiveness of this eye design is the fact that it is still widely used in both insects and crustaceans today (Levi-Setti, 1993, p. 29).
- Polystrate fossil tree passing through sedimentary rock suggesting rapid deposition. Joggins, Nova Scotia. Geological Survey of Canada, 1910. Neg. 15092. In 1987 Jerry MacDonald discovered a wide variety of beautifully preserved fossil footprints in the Robledos Mountains of New Mexico. Rumors were heard about "out of place" fossils but the site remained top secret. Finally a tantalizing article appeared in the Smithonian Magazine, July, 1992. The article acknowledged "what paleontologists like to call, 'problematica.'" It described what appeared to be large mammal and bird tracks that, "evolved long after the Permian period, yet these tracks are clearly Permian." With a little detective work and some luck we located the area and even more obvious "problematica."
- Because the fossil record show abrupt appearance and “stasis” (no change), the evolutionary theory of “punctuated equilibrium” was developed by Gould and Eldredge, which basically says we don’t see evolution in the fossil record because it happens fast in small isolated groups. It is an argument from lack of evidence. The Cambrian Explosion makes a shipwreck of their nice neat chart. Rather than seeing simple life forms such as worms and jellyfish appear to be folowed by trilobites and fish and the like, we instead see representations of all major phyla appearing AT THE SAME TIME! This obvious slap in darwin’s face has caused not a few Darwinists to famously modify the theory. Punctuated equilibrium, or “punk eek,” suggests that life exists with only minor adaptations within established kinds [observable microevolution, which no one disputes], but then goes rapid changes in short spurts which leave behind no transitional forms!
- The unusual appearance of this egg-laying, venomous , duck-billed, beaver-tailed, otter-footed mammal baffled European naturalists when they first encountered it, with some considering it an elaborate fraud. It is one of the few venomous mammals, the male platypus having a spur on the hind foot that delivers a venom capable of causing severe pain to humans. ‘ [T]here are functional challenges to Darwinian interpretations. For instance, in fish the head, shoulder girdle, and circulatory systems constitute a single mechanical unit. The shoulder girdle is firmly connected to the vertebral column and is an anchor for the muscles involved in lateral undulation of the body, mouth opening, heart contractions, and timing of the blood circulation through the gills.6 However, in amphibians the head is not connected to the shoulder girdle, in order to allow effective terrestrial feeding and locomotion. Evolutionists must suppose that the head became incrementally detached from the shoulder girdle, in a step-wise fashion, with functional intermediates at every stage. However, a satisfactory account of how this might have happened has never been given.’ Indeed, Tiktaalik’s fin was not connected to the main skeleton, so could not have supported its weight on land. The discoverers claim that this could have helped to prop up the body as the fish moved along a water bottom,3 but evolutionists had similar high hopes for the coelacanth fin. However, when a living coelacanth ( Latimeria chalumnae ) was discovered in 1938, the fins turned out not to be used for walking but for deft manœuvering when swimming. What is true between the Pre-Cambrian and Cambrian ages is also true between every other age - no transitional forms are found! The most frequently cited “intermediate form”, the reptile/bird “Archaeopteryx” is really a bird that has some reptilian features (like teeth). It has a “mosaic” of traits (some bird, some reptile), but each trait is fully-formed (including the feathers). There are animals alive today that are mosaics (e.g. the duckbill platypus and Haotzin chicks). A true reptile/bird intermediate would show reptilian scales “half-way” transformed into feathers.
- A tree typically grows one ring each year. Thus, if you cut a tree down and count the tree rings, you can determine how old the tree is. If there are 123 rings, the tree is, most likely, 123 years old. Counting tree rings is a good method for determining the age of a tree, but how does that help determine the age of artifacts in archaeology? Well, the first thing that you have to realize is that the appearance of a tree ring depends on several environmental factors for the year in which the ring was formed. The length of the growing season, the amount of rain, the average temperature, and several other factors all play a role in determining how wide and dark the ring being grown that year will be. As you look at a tree's rings, then, you will see patterns of wide rings, thin rings, dark rings and light rings. Those patterns are a result of the weather patterns that occurred in the tree's environment over its lifetime. Okay, fine, but how does that help an archaeologist? Well, since the weather in a given region affects the appearance of tree rings, archaeologists studying a certain region can cut down an old tree that is still alive. They can then look for distinct patterns of tree rings that correspond to several years of a given weather pattern for that region. Counting from the outside of the tree to the start of this special pattern will then tell archaeologists how many years ago that weather pattern occurred. Archaeologists find several such patterns and catalog them as master tree ring patterns for that region of the world. So, when an archaeologist discovers a log that was once used to build a home or something like that, he or she can look at the rings in the log and try to find one of those master tree ring patterns. If the archaeologist finds one, then he or she knows how many years ago the ring patterned formed, because that has already been determined. Since the archaeologist knows when that ring pattern was formed, he or she can then count the remaining rings on the tree that was discovered and determine when that tree was cut down. That will tell the archaeologist how long ago the people who cut down the tree were alive, and that will determine the age of the artifacts left by those people. Archaeologists have cataloged master tree rings patterns which have allowed them to date certain artifacts to as far back as 6600 B.C. Now before I go any further, I have to point out something that is very important. You must pay close attention here:
- How do you think ocean-dwelling creatures ended up fossilized under layers of sediment on the tops of mountain ranges? Marine fossils are found on almost every mountain range in the world (Alps, Andes, etc.), and provide clear evidence that the oceans covered the continents.
- requires guessing based on rock layers, which are determined by fossils