Evidence of Evolution

Evolution and the Fossil Record The horse series is used as evidence of evolution in the fossil record It shows the evolution of horse from Eohippus to the modern horse.

Evolution and the Fossil Record

Evidence: Miller-Urey Experiment Used to demonstrate how life may have began on Earth Ran an electric current through gases which created amino acids

Evidence: Miller-Urey Experiment

Evidence: Miller-Urey Experiment Questions / Issues with the Miller-Urey Experiment Produced building blocks for life (simplest amino acids) not life itself Argument is this is too big a leap to make Are the gases in the experiment the same ones as where present in the early atmosphere? Geologist since the 70’s have argued that the gases in this experiment were nothing like those of early earth’s atmosphere.

Evidence: Darwin’s Finches Used to demonstrate natural selection as a cause of evolution Due to selective pressures new species arise to fit niche

Evidence: Darwin’s Finches

Evidence: Darwin’s Finches Peter and Rosemary Grant studied finches on the Galapagos in the 70’s and 80’s When there was a dry year, mostly hard-to-crack seeds remained for finches Finches with large beaks survived easier By relating environment to beak size, the Grants showed that natural selection influences evolution

Evidence: Darwin’s Finches Questions / Issues with the Darwin’s Finches Although the finch species showed evolution, beak sizes returned to the original size after the rains returned (i.e. not net evolution) Some species of finches appear to be merging through hybridization

Evidence: Kettlewell’s Moths Peppered Moths Used to demonstrate natural selection Industrial revolution created soot that killed the lichens growing on trees and changed the background for the moths Moths were released on different colored bark. Ones that blended in were not eaten by birds Numbers of black moths surviving were high on dark bark, numbers of white moths were low When the color of bark changed so did the numbers of white and dark moths

Evidence: Kettlewell’s Moths Questions / Issues about this Kettlewell’s experiment These moths used in his experiment don’t rest on vertical surfaces. Did releasing the moths in a concentrated area produce unnatural behavior in the birds? Does this experiment represent a natural situation.

Evidence: Kettlewell’s Moths Is the change in moth coloration due to bird predation?

Evidence: Haeckel’s Drawings Tries to show evolutionary history in the development of embryos

Evidence: Haeckel’s Drawings

Evidence: Homologous Structures Similarity in characteristic resulting from a common ancestor Forelimbs of mammals are constructed with the same skeletal elements Similar features are not always from similar DNA Questions/Issue Homologous Structures are only considered that if common ancestry is assumed

Evidence: Homologous Structures

Evidence: Homologous Structures Vestigial Organs - describes homologous parts of organisms which have lost all or most of their original function in a species through evolution.

Evidence: Homologous Structures

Summary: Evidence of Evolution Fossil Record Suggestive of Evolution Miller-Urey Experiment Attempts to demonstrate origin of life Darwin’s Finches Demonstrates natural selection and niches Kettlewell’s Moths Demonstrates natural selection and fitness Haeckel’s Drawings Tries to evolutionary history via embryonic development Homologous Structures Draws evolutionary relationship between organisms based on similarities