OTHER EVIDENCE FOR EVOLUTION CHAPTER 5 SECTION 3 OTHER EVIDENCE FOR EVOLUTION

OTHER EVIDENCE SCIENTISTS COMPARE SIMILAR BODY STRUCTURES DEVELOPMENT BEFORE BIRTH DNA SEQUENCING

SIMILARITIES IN BODY STRUCTURE HOW IS IT POSSIBLE THAT TWO DIFFERENT SPECIES DEVELOP THE SAME BODY STRUCTURE? IT SEEMS MORE POSSIBLE THAT ONE SPECIES EVOLVED INTO ANOTHER SPECIES AND BROUGHT ALONG THE SAME TRAITS (VARIATIONS)

SIMILAR BODY STRUCTURES HOMOLOGUS STRUCTURES BODY STRUCTURES THAT ARE THE SAME IN DIFFERENT SPECIES. LOOK AT PAGE 160 FIGURE 13. WE SEE THE SAME TYPE OF BODY STRUCTURES IN THREE DIFFERENT SPECIES THE DIFFERENT COLORS COMPARE THE SAME BONES. AS YOU CAN SEE THERE ARE SOME CHANGES IN THE POSITION OF THE BONES BUT THEY ARE TO SIMILAR TO DEVELOP INDEPENDENTLY- THEY MUST HAVE EVOLVED

SIMILARITIES IN EARLY DEVELOPMENT AS EMBRYOS DEVELOP DIFFERENT SPECIES START OUT THE SAME BEFORE THEY SPECIALIZE. SEEMS REASONABLE SINCE THEY HAVE THE SAME BASIC GENES. WHEN THEY DEVELOP THE DIFFERENT ADAPATATIONS THAT HAVE EVOLVED START TO APPEAR AND WE SEE THAY ARE SO DIFFERENT THAY HAVE BECOME DIFFERENT SPECIES.

SIMILARITIES IN DNA WE KNOW THAT WHAT AAN ORGANISM LOOKS LIKE IS DETERMINED BY IT’S GENES (DNA SEQUENCES) REMEMBER THE DNA HAS THE DIRECTIONS TO MAKE THE PROTEINS THAT MAKE UP AN ORGANISM. THROUGH EVOLUTION MANY ADAPTIONS DEVELOP BUT THE BASIC STRUCTURES REMAIN THE SAME- THE ORGANISM ADAPTS TO A CHANGING ENVIRONMENT BUT THE BASIC DAN STRUCTURE REMAINS THE SAME.

COMBINING THE EVIDENCE IF WE TAKE ALL THE EVIDENCE IN THE DEVELOPMENT OF A NEW SPECIES WE SHOULD CONCLUDE THAT THE BASIC STRUCTURE IS THE SAME BUT THERE ARE DIFFERENCES (ADAPTIONS) WHEN THE DIFFERENCES BECOME SO DIFFERENT – A NEW SPECIES EMERGES.

BRANCHING TREE LOOK AT FIGURE 16 ON PAGE 163. IT IS EASY TO SEE THAT ONE COMMON ANCESTOR EVOLVED INTO THE RACOON AND LESSER PANDA AND ALSO INTO THE GIANT PANDA AND BEAR. IF WE LOOK AT THE RACOON AND LESSER PANDA WE SEE UNDER THEN IS A “V”AT THE BASE OF THE V WHAT WAS THERE

SECTION REVIEW 1. name the three types of evidence from modern-day organisms that scientists use to determine evolutionary relationships. 2. What are Homologous structures. 3. What information did scientists learn by comparing the early developmental stages of turtles chickens and rats? 4. If two species are closely related, what would you expect a comparison of their DNA base sequences to reveal?

Section review 4. If two species are closely related, what would you expect a comparison of their DNA base sequences to reveal? 5. most scientists today consider similarities in DNA to be the best indicator of how closely to species are related. Why do you think this is the case