More Than An EyeWitness Evidence for Evolution

Sources of Evidence From observation From studies of embryology Biochemistry From the fossil record From studies of DNA From studies of anatomy

EVIDENCE FROM FOSSILS From the fossil record

Transitional Organisms If evolution has occurred in the past there should be evidence of transitional organisms in the fossil record.

Archeopteryx Archeopteryx shows evidence of the evolution of birds from reptiles….there is evidence of feathers, a characteristic of birds, and claws, a characteristic of reptiles.

EVIDENCE FROM ANATOMY From studies of anatomy

Did you write down all your Guesses? IF SO: CLICK!!!!

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Identify how each organism uses its forelimb Frog Lizard Bat Human Lion Sea Lion bird balance Walking flying Multiple uses walking swimming

Anatomical Studies show Homologous parts – similar in structure but not necessarily function – evidence of evolution from common ancestor Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Anatomical studies show... Name two other organisms that have the ability to fly but have wings very different than those of the bird or the bat?

Analogous structures Butterflies or insects have wings but they are very different from the birds. These organisms do not have a common ancestor but have adapted to a similar environment. Again evolution explains the similarities. Copyright © The McGraw Hill Companies. Permission required for reproduction or display

Anatomical studies show Vestigial parts – why does a whale have a pelvis and femur bones if it has no hind limbs?

Vestigial structures Why does this salamander have eyes if it never sees the light of day?

Vestigial structures

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Why do these structures occur? These structures may be homologous to ones that had a function in the ancestors of these organisms thus suggesting their evolution from this common ancestor.

Anatomical Studies Anatomical studies of cells show a commonality in structure of the cell membrane among almost all living things. Does this suggest a common ancestor for all life?

EVIDENCE FROM EMBRYOLOGY From studies of embryology

Embryology Studies Even though it may not be apparent during the first stage (A) these five organisms are very different when born and at later stages of embryonic development. Why do they look so similar initially? Stage (A) A B C D E Copyright © The McGraw Hill Companies. Permission required for reproduction or display

Did you THINK about it. Did you write down all your Guesses Did you THINK about it? Did you write down all your Guesses? IF SO: CLICK!!!!

Embryology Studies The organisms are: Fish Salamander Chicken Rabbit Human Why would these five, so different looking organisms at birth, look so similar before birth?

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EVIDENCE FROM BIOCHEMISTRY

Studies of Biochemistry Species Sequence of Amino Acids in the Same part of the Hemoglobin Molecule Human Lys-Glu-His-Iso Horse Arg-Lys-His-Lys Gorilla Lys-Glu-His-Lys Chimpanzee Zebra Arg-Lys-His-Arg

Which organisms appear to be more closely related to each other? Human and chimpanzee have no differences in their amino acid sequence suggesting their close evolutionary relationship, they have a more recent common ancestor. Studies of other chemicals, like proteins used in digestion, show similar comparisons in these organisms.

EVIDENCE FROM DNA From studies of DNA

DNA From studies of DNA The sequence of the nucleotides making up their DNA would also be similar because DNA determines the sequence of amino acids in proteins.

DIRECT OBSERVATION OF EVOLUTION OCCURRING IN MODERN DAY ORGANISMS From observation

Observations of Evolution in modern organisms Mosquitoes resistance to insecticides Bacteria resistance to antibiotics New strains of Plasmodium that cause Malaria New strains of TB (tuberculosis) Peppered moth Darwin finches

Has and Does Evolution Occur? Scientists do not dispute that evolution does occur. Evolution is a FACT. How evolution occurs is not completely understood. Charles Darwin explained how evolution occurred through natural selection. Natural selection is a well documented THEORY uniting all of biology. Modern evolutionary theory uses ideas of genetics, particularly mutations, to help explain how evolution may occur. (Darwin didn’t know about mutations.)