2Evidence for Evolution Evolution (the transformation over a long period of time from one species into another) is a fact.
3Evidence for Evolution Evolution accurately and scientifically explains facts observed in the world.
4Evidence for Evolution Evolution is a theory just like the sun-centered system of Copernicus and Galileo is also a theory. It took over 200 years for people to accept it, but we now know it is true.
5What Are Fossils?Fossils are the naturally preserved remains, imprints, or traces of organisms that lived long ago.
6What Are Fossils? Includes bones, shells, and footprints. Microfossils can only be seen under a microscope.
7What Are Fossils? They determine: the relationships among organisms the approximate times when life first appeared on Earthwhen organisms became extinct
8What Are Fossils?A paleontologist is a scientist who studies fossils.
9How Are Fossils Formed?Decomposition (breaking down into substances that can be used by other organisms) is part of an organism’s life cycle.
10How Are Fossils Formed?For an organism to become a fossil, it must be protected from decomposers, scavengers, and environmental factors.
11PermineralizationWhen substances inside the tiny spaces of dead organisms decompose, water seeps into the empty spaces and deposits minerals, and preserves them.This process, permineralization, forms a strong, rock-like fossil.Petrified Fossil
12ReplacementOnly the hard parts of an organism are replaced by minerals in replacement.Only the shape of the original organism remains.
13CarbonizationWhen a dead organism is quickly buried under conditions without oxygen, the elements of the living tissue are removed, leaving behind just the element Carbon.A thin, usually black, carbon film remains and is compressed by sediment, preserving the image of the organism on a rock.
14Molds and CastsWith mold and cast fossils, no parts of the original organism remain.Molds are imprints from an organism, such as a shell or the skin of an animal.A mold looks like a hollow impression of the organism.CastMold
15Molds and CastsA cast is created when molds fill in with sediment that hardens into rock.A cast looks like a stone 3D version of the organism.CastMold
16Original MaterialOrganisms preserved in materials such as amber, tar, and ice are called original material fossils.They are rare and provide much information because none of the hard or soft structures have been altered or replaced.
17Original Material The 3 types are tar, amber (sap), and ice.
18What Do Fossils Tell Us?Much of the evidence for evolutionary relationships comes from fossils.
19What Do Fossils Tell Us?Scientists also study fossils to understand some processes and rates of evolution.
20What Do Fossils Tell Us?Fossils provide a record of different organisms that lived in the past.
21Relative Fossil AgesGenerally, younger fossils are in shallow sedimentary rock layers and older fossils are in deeper layers.
22Relative Fossil AgesFossils can be compared by their age relative to each other (relative age) and the changes to species can be documented.
23Species and Environmental Changes The fossil record is a timeline showing all the known fossils and their placements in rock formations.
24Species and Environmental Changes The fossil record is evidence of the evolution of plants and animals, and their extinction.
25Species and Environmental Changes There are not always “transitional fossils” - a fossil that gives us information about a transition from one species to another.
27Species and Environmental Changes Not EVERYTHING gets fossilized, and many fossils are destroyed because of plate tectonics.This causes gaps in the fossil record.
28Species and Environmental Changes It’s NOT like there is a video camera recording EVERYTHING.It’s more like a still camera taking snapshots.
29Species and Environmental Changes Not a SINGLE fossil is in the wrong place and the wrong time.There are no rabbit fossils in the Precambrian time.If we did find rabbit fossils in the Precambrian time, we could disprove evolution.
30Species and Environmental Changes Fossils provide evidence of how life and environmental conditions have changed throughout time.
31Species and Environmental Changes Scientists use fossils to determine how organisms lived, what they ate, and what kind of environment they lived in.
326.1 Fossils and EvolutionABCD1. What describes the deposit of minerals into the tiny spaces that have decomposed in an organism?A permineralizationB decompositionC replacementD molds
336.1 Fossils and EvolutionABCD2. What describes the preservation of the impression of an organism if no parts of the organism remain?A carbonizationB replacementC molds or castsD original material
343. What are the most commonly found fossils? A original material 6.1 Fossils and EvolutionABCD3. What are the most commonly found fossils?A original materialB hard structuresC soft structuresD footprints
354. What does a paleontologist study? A DNA BCD4. What does a paleontologist study?A DNAB classification of organismsC fossilsD embryos
36ABCD5. What does the depth of a fossil in the rock layer tell us about the fossil?A how old it isB how it diedC how it evolvedD how it lived