Biology-B6-Evidence for Evolution 0.0 / 5 ? BiologyEvolution, extinction and natural selectionGCSEAQA Created by: tonisha_Created on: 25-02-23 13:55 Fossils are the remains of? organisms 1 of 23 From how long ago? millions of years ago 2 of 23 Found in? rocks 3 of 23 HOW THEY FORM --------------------- What are the three ways fossils form? preservation replacement by minerals casts and impressions 4 of 23 Preservation is where no? decay takes place 5 of 23 This can happen when what is absent? conditions for decay are absent 6 of 23 For example, a fossil may form in amber when there is an absence of? oxygen 7 of 23 Fossils may form in glaciers due to? it being too cold 8 of 23 Or there may not be enough? water 9 of 23 Replacement by minerals is whereas the organism decays? it forms a rock like substance 10 of 23 This is how? most fossils are made 11 of 23 Cast and impressions happen when an organism is buried? in a soft material like clay 12 of 23 The soft material will then? harden around the organism 13 of 23 Leaving a? a cast 14 of 23 What is an example of a cast? plant roots 15 of 23 What is an example of an impression? footprints 16 of 23 PROBLEMS --------------------- Many of Earths early forms of life were? soft bodies 17 of 23 This means they didnt have? a shell or skeleton 18 of 23 Soft bodied organisms rarely form? fossils 19 of 23 And if they did they were ? destroyed 20 of 23 Due to the Earths? geological activity 21 of 23 Therefore fossil records? are incomplete 22 of 23 And scientists are uncertain? on how life on earth truly began 23 of 23
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