intermediate states between an ancestral form and that of its descendants are referred to as transitional forms. There are numerous examples of transitional forms in the fossil record, providing an abundance of evidence for change over time.
Mammals,amphibians, birds, and reptiles are tetrapods. Transitional Organisms. intermediate states between an ancestral form and that of its descendants are referred to as transitional forms. There are numerous examples of transitional forms in the fossil record, providing an abundance of evidence for change over time.
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We can identify homologous structures by tracing their embryological development. Some if our middle ear bones, for example, are homologous with jaw bones of reptiles and bones supporting gills in fish.
They are formed in a number of ways: an animal or plant may be frozen in ice, trapped in amber, or buried in a thick layer of mud. The entombed organism is thereby protected from being eaten by scavengers or rapidly decomposed by bacteria. Over time, if conditions are right, the organism's shape is preserved.
They are formed in a number of ways: an animal or plant may be frozen in ice, trapped in amber, or buried in a thick layer of mud. The entombed organism is thereby protected from being eaten by scavengers or rapidly decomposed by bacteria. Over time, if conditions are right, the organism's shape is preserved. Logically they are as old as the rocks that encase them, so if you know the age of the rocks, you then know the age of the fossil. Can also use radiometric dating and relative dating.
This development homology is strong evidence that all vertebrate animals are related by common ancestry. Genetic changes over time have introduced modifications in later stages that give rise to distinct species with vast physical differences. DNA Evidence of Evolution.
The homologous structures may have arisen independently in the two species that are closely related
Fossils can be dated using a microscope to examine tissue.