What are 3 types of fossils and how are they formed?
956444
the types of fossils are:\n\n1.  body fossils - fossils of the actual body or body parts of an organism, whether altered or not\n2.  trace fossils - any evidence of past life that is not a body fossil.  Examples include tracks, trails, burrows, borings, impressions, molds, casts.\n3.  pseudofossils - are things that appear to be fossils but are not.  The most deceptive of these are the lacy dendrites of manganese dioxide.  Often, inorganic rock concentrations are thought to be fossilized soft parts of various animals. \n\nto form a fossil, there are important prerequisites:  there should bequick burial & there should be a hard part or parts of the organism. the the organixm is notquickly buried, bacteria or other animals may destroy it.  if the organism dies in an anaerobic environment (absence of oxygen) the soft tissues may also be preserved.
1092991
Try a museum of natural science.  You can find all kinds of fossils there.
133519
The VERY BEST online guide to trilobites is here:\nhttp://www.trilobites.info/index.html\nHe even has a long FAQ, as well as lots of photos and diagrams. \n\nThe Australian Museum has a good write-up describing them:\nhttp://www.austmus.gov.au/palaeontology/research/trilobites02.htm\n\nHere is a good set of photos of specimens:\nhttp://www.yale.edu/ypmip/\n\nHere is another set of 46 photos of specimens:\nhttp://www.paleoportal.org/fossil_gallery/search.php
1160643
maybe this can help\n\nhttp://en.wikipedia.org/wiki/Fossils
840440
Index fossils are fossils of creatures that existed for a short period of time. A good index fossil should also be distinctive (hard to confuse with other creatures from a different period;) wide ranging (its helpful if the fossil appears worldwide) and common (if fossils of the creature are rarely found they are not much use!)\n\nSo, once you know that, say, a certain type of trilobite lived between 570 amd 500 million years ago, you know that any rocks with that trilobite fossil in are 570-500mn years old. This also gives a date for any other fossil found in the same strata.
363226
http://www.infothis.com/find/Hallucigenia/ (same as above, only with the source)\nHere's what it looks like:\nhttp://www.nmnh.si.edu/paleo/images/fhallu.gif\n\nHere are possible reconstructions:\nhttp://gsc.nrcan.gc.ca/paleochron/09_e.php\nhttp://evolution.berkeley.edu/evolibrary/article/0_0_0/cambrian_14\n\nI recommend you Stephen Jay Gould's book "Wonderful life" for a detailed and also entertaining account of Burgess Shale fossils.
962499
There are many different sedimentary rocks but only three basic causes.\n\nFirst is where rock is weathered out and is washed down into valleys and rivers where it forms a mud and is then pressured to turn into rock.\n\nThe other is the sea floor where the same silt settles and becomes a thick layer over the years.  Then either the sea recedes or the land is thrust up leaving the mud high and dry as sedimentary rock.\n\nLastly we have limestone and chalk where sea creatures die, sink to the ocean floor and accumulate.  This then follows the same upthrust or ebb of the sea and is exposed as rock on the mainland.
413020
Fossils (from Latin fossus, literally "having been dug up") are the mineralized or otherwise preserved remains or traces (such as footprints) of animals, plants, and other organisms. The totality of fossils and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record. The study of fossils is called paleontology. Because fossils are by their nature old, the word has also entered the modern vernacular as a derogatory term for an elderly person. Fossils are like coal, oil, etc or u can try these:\n\n\nKind of fossils:\n1 Trace fossils \n2 Microfossils \n3 Resin fossils \n4 Pseudofossils \n5 Living fossils
45880
Here is a web site with pictures of Quaternary plant fossils.\nhttp://www.paleoportal.org/fossil_gallery/search.php?taxon_id=14&period_id=7\n\nPlants in the Quaternary include Angiosperms, ferns and relatives, gymnosperms (includes conifers,  gnetophytes, & cycads), horsetails, lycophytes, mosses, liverworts, hornworts, and phytoliths.\n\nThe site below will help you explore these groups.
1018700
The fossilization process begins at the time of an organism's death. Rapid burial under sediments is key for the fossilization process to begin. This prevents decomp from bacteria & protects the carcass from scavengers.\n\nAfter the intial process, it will take thousands of years for a fossil to form. Fossils occur in sedimentary environments. This usually involves lots of water & the deposition of sediments over lengthy amounts of time.\n\nLayer after layer is deposited until the pressure squeezes the water out & lithifies the rock.\n\nSome replacement of bones & teeth may take place. In this process, minerals replace other minerals in the hard parts of an organism.\n\nHard parts are usually the only thing to survive the fossilization process. Soft parts decompose too easily.
861869
The major lines of evidence are:\n1) the paleoenvironments the species lived in, as evidenced by the sedimentary rocks and other fossils\n2) analogy with related species\n3) functional morphology\n4) taphonomy and trackways\n\nThings you might look up are ammonites, trilobites etc
1184117
http://www.psigate.ac.uk/newsite/earth_timeline.html\nhttp://www.sdnhm.org/fieldguide/fossils/timeline.html\nhttp://www.talkorigins.org/origins/geo_timeline.html\nhttp://en.wikipedia.org/wiki/Geologic_timescale\n\nI hope these help.
669472
The oldest animal fossils are called Vernanimalcula and are aged at 600 million years.  These are the first organisms discovered that exhibit true animal characteristics.  I don't think bacteria count as an animal....
308686
Geologic time is divided up into 4 categories\n     - Eon (being the longest)\n     - Era\n     - Period\n     - Epoch (being the shortest)\n\nThe Eon that marks a significant bloom of life on Earth is the Phanerozoic. It spans from 543 million years ago to the present day. Within this Eon, there are three eras; the Paleozoic, Mesozoic, and Cenozoic.  the Paleozoic, or ancient Era, contains 6 Periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous (which can be broken into the Mississippian and Pennsylvanian Epochs), and Permian Periods.  The Mesozoic Era, the age of the Dinosaurs, can be broken into three Periods; the Triassic, Jurassic, and Cretaceous (which can be broken into the Lower and Upper Epochs) Periods. The Cenozoic Era, the Age of Mammals, is a weird one. It is split into 4 Periods that overlap, the Paleogene, Tertiary, Neogene, and Quaternary Periods.  These are split evenly into 7 Epochs, the Paleocene, Eocene, Oligocene,Miocene, Pliocene, Pleistocene, and Holocene, the Epoch we are in right now.  Now that I'm through with the confusing part, I can show you what it looks like in a Diagram :)\n\nPhanerozoic Eon\n   -- Paleozoic Era\n        ---Cambrian Period\n        ---Ordovician Period\n        ---Silurian Period\n        ---Devonian Period\n        ---Carboniferous Period\n             ----- Mississippian Epoch\n              ----- Pennsylvanian Epoch\n        --- Permian Period\n   -- Mesozoic Era\n        ---Triassic Period\n        ---Jurassic Period\n        ---Cretaceous Period\n            -----Lower Epoch\n            -----Upper Epoch\n   -- Cenozoic Era\n        ---Paleogene Period\n            ------ Paleocene Epoch\n            ------ Eocene Epoch\n        --- Tertiary Period\n            ----- Oligocene Epoch\n            ----- Miocene Epoch\n        --- Neogene Period\n            ----- Pliocene Epoch\n            ----- Pleistocene Epoch\n        --- Quaternary Period\n             -----Holocene Epoch\n\nWe are currently in the Holocene Epoch of the Quaternary Period of the Cenozoic Era of the Phanerozoic Eon.\n\nTo answer your question, Eon is the longest division of geologic time :)
862177
.  Animals which have a simple evolutionary history are usually soft bodied, and soft bodies animal do not leave good fossils.  It is easy to find analogs for evolutionary steps toward certain animals, the whale for example,  but finding an clear-cut sequence of fossils is difficult.\n.  But, looking at analogs, consider the weasel, the otter, the seal, the manatee and the whale.  The difference between any two steps in this sequence is fairly small, but the difference from one end to the other seems quite large.\n.  There are enough fossils whose ages may be determined that, studied as a group, studied as a group, they demonstrate an increase in complexity of organisms over time and indicate familial relationships.  Bony headed fishes, known only from fossils, were the ancestors of fish like the coelacanth.  Fishes like the collegian were ancestral to both modern fishes and the fish which pulled themselves up from the water on strong, bony fins.\n.  The horse has some obvious ancestors, but the the fossil record of those ancestor becomes weaker as you go back in time.  The fossil record  between shrew like mammals and those creatures which had some horse like characteristics has big gaps in it..
1057852
It takes a very long time.  The oldest fossils are about 3.5 billion years old, but many are not nearly that old.  The youngest are probably only about 23 million years old or even less.\n\nThese links are helpful.
222018
rock formed from layered sediments that pile up and squeeze together, providing clues to the earth's past. an example is sandstone.