The Fossil Record

Depict the history of life on this timescale. On your timeline, show: Mesozoic, Paleozoic and Cenozoic eras Two major climate changes characteristic of each era Major changes to plant and animal life that took place during this time Activity: Construct a time-line of the key events in the history of life on Earth Essential CAPS In this exercise learners are required to combine all the information given on the history of life and to depict this information onto a simple geological timescale of their own. Learners can do this in poster format or as a class exercise. They may work individually or in small groups of 2 to 4. Pictures from the Internet to illustrate their time scale can be used.

Social Science History: Society and Science History TimeLine

Biological evolution is change in the characteristics of living organisms over generations. Despite your vastly superior tastes in music and fashion, you probably look vaguely like your parents, just as they look vaguely like their parents. For all of recorded history, people have looked more or less the same: Hairdos differed, but the basic body plan stayed the same for as far back as the history books go. But if you were to go back further in time, a couple million years before anybody figured out how to write, your ancestors would still have two eyes, two ears, a nose, a mouth, a head sitting atop an oblong body with two arms and legs.

Aboslute age dating Fossil Geologists Half-life Relative age dating HELPFUL TERMS Paleontologists Isotope Radioactive decay Determining the Age of Rocks and Fossils 1 New York State Standards 1 Inside This Packet New York State Standards Middle School Activity Activity: Relative Age of Rocks Earth Science – Post Module 3 Middle School Page.

At the same time, it should reveal an example of pseudoscience which should be part of any effort to improve science literacy and critical thinking. Students are taken through a combination of some background information and interactive experiences, and checked frequently by questions to confirm understanding. The narrative includes concepts of isotopes, radioactive decay, half-life, mineral formation, age analyses, Fair Test questions , and isochrons.

The lesson can be used as a one-day team activity, individually in class, or as a self-teaching homework assignment. It is intended to either stand by itself, or to serve as a useful introduction to the very effective online interactive Virtual Age Dating Tutorial. Several independent lines of evidence confirm that the Earth is billions of years old.

“World’s Oldest Fossils” Might Actually Be Simple Rocks, And We’re Here For The Drama

Microbial mats[ edit ] The fossil Charniodiscus is barely distinguishable from the “elephant skin” texture on this cast. Microbial mats are areas of sediment stabilised by the presence of colonies of microbes that secrete sticky fluids or otherwise bind the sediment particles. They appear to migrate upwards when covered by a thin layer of sediment but this is an illusion caused by the colony’s growth; individuals do not, themselves, move.

Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods. Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better.

Richard Cowen’s Chapter Eight: Leaving the Water – images – curent page , , to , , years ago Eurypterids, otherwise known as sea scorpions. Wikipedia Late Ordovician survivals and extinctions: There were no land animals and extinctions were confined to water life. There were two distinct extinctions roughly a million years apart. The first of these began about million years ago. Together, these extinctions may have removed about 85 percent of species of marine animals. All of the major animal groups of the Ordovician oceans survived, including trilobites, brachiopods , corals, crinoids and graptolites, but each lost important members.

Widespread families of trilobites disappeared and graptolites came close to total extinction. Graptolites rock writing are thought to be horny skeletons of small creatures. Some are pictured here from the Observers Book of Geology , Their many different forms have enabled beds of ancient rock to be identified. The earliest graptolites appear in Cambrian rocks and the last in Carboniferous , , to , , years ago Silurian period.

Debunking Evolution

Godthelp in Hill, Robert S. White, , The Nature of Hidden Worlds: Australian Conservation Foundation, Melbourne. Michael Archer, Suzanne J. Gehling, Kathleen Grey, Guy M. Franklin, The revolution that didn’t arrive:

Necessary materials, determine the fossil find. Learn vocabulary words about how do relative dating 8 9 clues to determine the worksheet answers ap biology answers may june relative dating. Tip: earth’s past life science: a fossil record to science 10 unit worksheets .

Dating the Fossil Record Activity. Record the samples in order from bottom to top oldest to youngest in. Write an X in the appropriate column to indicate which fossil or fossils are present in each sample. You have received nine rock samples from a paleontologist in California. Your job is to arrange the. Dating the key fossil record worksheet. Have had some measure of success, i told him, you know, i think there actually is a dating guide for our era of free.

Dating the fossil record worksheet answers. Detailing demographics and preferences of its south african inception in the year with the sole aim of reducing. Dating the Fossil Record. Results from absolute dating methods. Globus Bogus , Fungus. Answers to Section G:


Scientific measurements such as radiometric dating use the natural radioactivity of certain elements found in rocks to help determine their age. Scientists also use direct evidence from observations of the rock layers themselves to help determine the relative age of rock layers. Specific rock formations are indicative of a particular type of environment existing when the rock was being formed.

For example, most limestones represent marine environments, whereas, sandstones with ripple marks might indicate a shoreline habitat or a riverbed. The study and comparison of exposed rock layers or strata in various parts of the earth led scientists in the early 19th century to propose that the rock layers could be correlated from place to place.

This has created some confusion, and since it is so important to a fully accurate understanding of the history of life, we’re going to take a close look at just how the science of geological age dating, “geochronology”, works.

January Fossils provide a record of the history of life. Smith is known as the Father of English Geology. Our understanding of the shape and pattern of the history of life depends on the accuracy of fossils and dating methods. Some critics, particularly religious fundamentalists, argue that neither fossils nor dating can be trusted, and that their interpretations are better. Other critics, perhaps more familiar with the data, question certain aspects of the quality of the fossil record and of its dating.

These skeptics do not provide scientific evidence for their views. Current understanding of the history of life is probably close to the truth because it is based on repeated and careful testing and consideration of data.


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The Fossil Record “I tell you, if these become silent, the stones will cry out!” Lk (NASB) Taxonomy is the branch of science that deals with classifying life. For example, taxonomy is used to distinguish plants from animals, mammals from fish, and tigers from horses. The two main dating methods used to estimate fossil age.

Such evidence may take the form of body fossils both plant and animal , trace fossils or ichnofossils physical features formed in rock due to animal-sediment interaction , and chemical trace fossils chemical evidence of life processes preserved in minerals within the rocks. Fossilization refers to the series of postmortem after-death processes that lead to development of a body, trace, or chemical fossil.

For original hard parts e. Fossil shells may be represented by external or internal steinkern sediment molds. Soft parts of plants or animals may also be mineralized and preserved as fossils in the process of carbonization. Soft tissue can be preserved as fossil material under special conditions where bacteria and moisture are excluded e. Fossils and their enclosing sediment or sedimentary rock are carefully studied in order to reconstruct ancient sedimentary environments and ancient ecosystems.

Glencoe Earth Science Chapter Fossils and the Rock Record

Anabaena The Three Domains of Life As previously noted, stromatolites are most often described as biogenically-produced structures formed by colonies of photosynthesizing cyanobacteria. However, this is an enormous oversimplification given that the weight of scientific evidence suggests that all three domains of life the Archaeans, Eubacteria, and Eukaryotes appeared in the Archaean Era, and thus the so-called microbial mats would have contained representatives among all three domains.

Just how and when the base of the tree of life split into the three main branches remains one of the most important questions in all of biology and science, and is the source of constant scientific dispute. Which of the prokaryotes came first, the Archaeans or the Eubacteria remains unresolved, and a consensus has emerged that these primitive microorganisms laterally exchanged genes further confounding attempts to validate what begat what during to course of early evolution on earth.

Lateral gene transfer belies the concept of the single common ancestor see Woese,

*Life Science: Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; most of the species that have lived on the earth no longer exist. *Earth and Space Science: Fossils provide important evidence of how life and environmental conditions have changed.

This section explains the different types of fossils. This rare form of preservation preserves life form with some tissue or skin intact. Specimens that are preserved this way are very fragile. Natural mummification usually happens in dry and cold places where preservation happens quickly and effectively. Mummification is not truly fossilization. These are imprints of the organism embedded in rocks. These are formed when external molds are filled with sediment. These occur when sediment fills the shell of a deceased organism such as a bivalve or a gastropod.

These occur when minerals slowly replace the various organic tissues of an organism. The most common mineral to cause petrification is silicon, but other minerals also work. These occur when over time all parts of the original organism except the carbon are removed from the fossil over time. The remaining carbon is the same carbon that the organism was made of.

This occurs when original minerals in the fossil over time revert into more stable minerals, such as an apatite shell recrystallizing into the more thermodynamically stable calcite.


Mineralogy As a discipline, mineralogy has had close historical ties with geology. Minerals as basic constituents of rocks and ore deposits are obviously an integral aspect of geology. The problems and techniques of mineralogy, however, are distinct in many respects from those of the rest of geology, with the result that mineralogy has grown to be a large, complex discipline in itself.

Nepheline greasy light gray , sodalite blue , cancrinite yellow , feldspar white , and ferromagnesian minerals black in an alkalic syenite from Litchfield, Maine, U.

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Student recognizes there are many different types of fossils such as entirely preserved organisms, structures such as teeth and bones, or trace fossils. Paleontologists can use the preserved structures from organism to calculate the age of the fossil and to determine the size and structure of the organism. Since the soft structures do not fossilize well, paleontologists must infer the appearance of the soft tissue.

Paleontologists also infer the behavior and diet of fossilized organisms. There are gaps in the fossil record because not every organism dies under conditions that allow it to become fossilized. Also, many fossils remain buried and have not been discovered yet. However, scientists use the current fossil record to predict the transitional fossils that most likely existed. Response does not address all parts of the question.

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What about the fact that the “simple” organisms are buried in the lower levels and the more “complicated” ones are buried in the higher levels? Doesn’t this fact support the notion that simple organisms evolved into more and more complex organisms over time, with the more complex organisms buried and fossilized above the earlier and simpler life forms?

Certainly this seems like a very logical assumption. But, things just aren’t that easy. There are a number of potential problems with this interpretation of the fossil record. For example, it is interesting to note that some general kinds of fossilized creatures are very generally found in the same relative vertical orientation, with respect to each other in the fossil record, that they would have naturally been found in during life.

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Before the scientific era, people often made up imaginative stories to explain what they saw in the world. The scientific method changed that by requiring rigorous experimentation to test hypotheses and determine what is real. With the Theory of Evolution, people are back to making up imaginative stories. The primary advantage of complete metamorphosis is eliminating competition between the young and old.

Larval insects and adult insects occupy very different ecological niches. Whereas caterpillars are busy gorging themselves on leaves, completely disinterested in reproduction, butterflies are flitting from flower to flower in search of nectar and mates. Because larvas and adults do not compete with one another for space or resources, more of each can coexist relative to species in which the young and old live in the same places and eat the same things. Ultimately, the impetus for many of life’s astounding transformations also explains insect metamorphosis: Nevertheless, “biologists have established a plausible narrative about the origin of insect metamorphosis, which they continue to revise as new information surfaces.

In response to this unfavorable situation, some pro-nymphs gained a new talent: