Index Fossil Reading and Questions Worksheet

fYidex Fossi/s Fossils аге the preserved remains of living things from 10,000 уеагs ago ог mоге. Usually fossils form when organisms аге quickly buried in sediments апd then аге replaced Ьу stone and minerals over time. This leaves behind an impression, model, ог remains of an arganism ог its activity. There аге fossils of animals, plants, fungi, and еvеп tiny fossils of bacteria and microscopic organisms. Paleontologists аге the scientists who study fossils and excavate (dig) them from the ground. Fossils help scientists to learn about what life was like in Earth's past- before humans. Fossils have also helped scientists learn about the climate апd еvеп where the continents were in the past оп Earth. We call the history of the Earth geologic time. Fossils сап Ье found underground where they have to Ье excavated (dug up), ог they сап Ье found оп the surface due to moving tectonic plates and erosion. Fossils form in sedimentary rock. When sediments like реЬЫеs, sand, and soil аге deposited оп the ground Ьу wind, water, ог gravity they сгеаtе а layer. Over time many layers build up like the layers of а cake. These layers of sedimentary rock аге called strata. The law of superposition states that the bottom layer in strata is the oldest and the top layer of strata is the youngest. So as you dig down in strata the layers are getting older and older. The same thing is true for fossils found in the rock layers. lf you find two fossils and one fossil is above the other fossil in the rock strata, the one оп top is younger than the lower fossil. The law of superposition helps us to find the relative ages of different fossils- which fossils are older and younger. Certain fossils help scientists know what time period а layer of rock came from just Ьу looking at it. This allows scientists to Ье more accurate with their relative dating. These fossils аге called index fossils. А fossil has to meet three criteria iп order to Ье cansidered an index fossil. An index fossil is а fossil that is abundant. Abundant meons it is easy to find. An index fossil also need to Ье widespread which means it is found all over the world. Lastly, an index fossil n eeds to Ье short-lived which means it only existed for а short period of time. Let's look at an example of an index fossil. Ап example of an index fossil is an ammonite shell. Ammonites were organisms that lived in shallow ports of осеапs all over the world. They looked like octopi with spiral shells. There were many different varieties that evolved quickly and lived fог а short period of time. lf we find n ammonite fossil we know that the rock layer it is iп is hundreds of millions of years old. � The exact kind of ammonite found will give а more exact date. � . ), ; . Fossils are the preserved remains of living things. They show us how life, landscapes, and climate have changed over time and how living things responded to those changes. sedimentary rocks fossils arent formed from igneous rocks because igneous rocks are formed from lava or magma a layer or series of layers of rock in the ground Radiometric dating is more accurate than relative dating because it provides an exact date rather than a range of dates. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time. yes it would because they are cool because it would break the shark eggs are older because they were found below the flowering plant fossils. Microfossils, which are fossils of microscopic organisms, are also useful index fossils. A useful index fossil must be distinctive or easily recognizable, abundant, and have a wide geographic distribution and a short range through time. yes yes no no