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Evidence of Evolution . By: Sarah Sarsam. Transitional Forms. Transition fossils : Many fossils have been found which appear to have the characteristics of two different groups of organisms.
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Evidence of Evolution By: Sarah Sarsam
Transitional Forms • Transition fossils: Many fossils have been found which appear to have the characteristics of two different groups of organisms. • Evolution from ancient reptiles to mammals is a series of transition fossils and is well documented. • There are two famous transition fossils and they are the lobe-fin fish, which indicates that amphibians may have evolved from fish ; andarchaeopteryx, which provides evidence for the common ancestry of birds and reptiles
Biogeography • Biogeography : Through geographical regions there is a relation to the study of living things. • Darwin and Wallace used biogeography as evidence of evolution. • They noticed that species living in the same area were more similar to each other than to species living in similar habitats far apart. • This shows that species evolved due to the selective pressure in their own habitats.
Comparative Embryology • Comparative embryology is the branch of embryology that compares the development of embryos of two or more species.
Homologous Structure • Homologous structures are structures found in plants or animals that have the same origin, but not necessarily exactly the same form or the same function. • The pentadactyl limbs of vertebrate animals (mammals, reptiles and amphibians) are examples of homologous structures. All of these groups have limbs with five digits (finger-like structures) which have the same basic structural plan, but have altered (adapted) to differentenvironments and ‘life-styles’
Comparative DNA • Scientists have found that DNA and the proteins it produces can provide evidence about evolution. • If 2 new species evolve from a common ancestor, their DNA and protein molecules slowly change and become different. • DNA and other biochemical evidence can be used to check the accuracy of evolutionary trees already worked out from fossils or from the study of structural homologies. • The number of differences is proportional to the time since they separated and allow the construction of evolutionary trees.