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Evidence of Evolution. Evidence of Evolution. Fossil Record Homologous Body structures Similarities in Embryology Biochemical Evidence. Evidence of Evolution: The Fossil Record. Fossil record provides evidence that living things have evolved

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evidence of evolution1
Evidence of Evolution
  • Fossil Record
  • Homologous Body structures
  • Similarities in Embryology
  • Biochemical Evidence
evidence of evolution the fossil record
Evidence of Evolution:The Fossil Record
  • Fossil record provides evidence that living things have evolved
  • Fossils show the history of life on earth and how different groups of organisms have changed over time
relative dating
Relative Dating
  • Can determine a fossil’s relative age
  • Performed by estimating fossil age compared with that of other fossils
  • Drawbacks – provides no info about age in years
absolute dating
Absolute Dating
  • Can determine the absolute age in numbers
  • Is performed by radioactive dating – based on the amount of remaining radioactive isotopes remain
  • Drawbacks - part of the fossil is destroyed during the test
slide7

Radiometric dating uses decay of unstable isotopes.

  • Isotopes are atoms of an element that differ in their number of neutrons.
  • A half-life is the amount of time it takes for half of the isotope to decay.
primate fossils
Primate Fossils

Australopithecus Homo erectus Homo sapien

evidence of evolution homologous body structures
Evidence of Evolution:Homologous Body Structures

Turtle

  • Structures that have different mature forms but develop from the same embryonic tissues

Ex: Wing of bat, human arm, leg of turtle

Alligator

Bird

evidence of evolution homologous structures

Molefoot

Batwing

Human hand

Evidence of Evolution:Homologous Structures
  • Features that are similar in structure but appear in different organisms and have different functions.
  • Strong evidence for common ancestor.
  • Ex: forelimbs of humans, bats and moles.
analogous structures
Analogous Structures
  • Structures that perform a similar function.
    • Not evidence of common ancestry.
vestigial structures
Vestigial Structures
  • Remnants of organs or structures that had a function in an early ancestor.
  • Ex: Ostrich wings, used for balance but not flight
  • Ex: Humans’ appendix
evidence of evolution similarities in embryology
Evidence of Evolution:Similarities in Embryology

In their early stages of development, chickens, turtles and rats look similar, providing evidence that they shared a common ancestry.

evidence of evolution biochemical similarities
Evidence of Evolution:Biochemical Similarities
  • Scientists study nucleotide sequences in DNA and proteins in different organisms to determine ancestry.
  • If the organisms are closely related they will have similar sequences of nucleotides in their DNA and arrangement of amino acids in proteins.
evidence of evolution biochemical similarities1
Evidence of Evolution:Biochemical Similarities

The more similar the amino acid sequence, the more closely related the organisms are.

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