Fossils and relatedness – basic principles
How it works
Fossils are preserved remains, impressions, or traces of living things from earlier geological eras, which are usually found in rock layers, especially in sedimentary rocks. They provide important clues about life in Earth’s history and help to reconstruct relationships between species. Age determination is carried out through relative dating based on the sequence of layers and through absolute dating, for example using radiometric methods. Index fossils are fossils of species that existed for only a relatively short geological time, but were widely distributed; this helps to classify rock layers in time. Homologous structures indicate common ancestry, while analogous structures indicate similar adaptations without close relatedness.
Fossils make it possible to draw conclusions about the development of life and the relatedness of organisms by documenting morphological features, chronological classification, and distribution.
An example
What is meant by an index fossil?
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50 Exercises
To the learning unit →Own explanation and own practice exercises by AmyMath. Subject reference framework: Biology. The topic assignment may vary by federal state.