EVIDENCES OF EVOLUTION“NOTHING IN BIOLOGY MAKES SENSE EXCEPT IN THE LIGHT OF EVOLUTION”

EVIDENCES OF EVOLUTION

• EVOLUTION HELPS EXPLAIN THE UNITY OF LIFE, WHICH BASICALLY STATES THAT ALL LIFE CAME

FROM A COMMON ANCESTOR

• EVOLUTION HELPS EXPLAIN THE DIVERSITY OF LIFE – DIVERSITY IS VARIETY OF SPECIES FOUND IN

A GIVEN AREA.

• MAJOR EVIDENCE THAT ALL SPECIES EVOLVED FROM A COMMON ANCESTOR:

• ALL SPECIES SHARE DNA/RNA AS A WAY OF STORING AND TRANSFERRING GENETIC MATERIAL

• ALL SPECIES SHARE THE SAME 20 AMINO ACIDS THAT BUILD UP THEIR PROTEINS

• ALL SPECIES USE THE SAME TRIPLET CODE (CODON) TO CODE FOR BUILDING AMINO ACIDS

THE THEORY OF EVOLUTION• CHANGE OVER TIME

• PEOPLE USED TO THINK THAT SPECIES DID NOT CHANGE

• DARWIN WAS NOT THE FIRST PERSON TO COME UP WITH THE THEORY OF EVOLUTION

• MANY SCIENTISTS CAME UP WITH THE IDEA THAT SPECIES CHANGE, THEY JUST DIDN’T KNOW HOW

JOHN BAPTISTE LAMARCK

• FRENCH BIOLOGIST (1744 – 1829)

• LAMARCK KNEW THAT SPECIES CHANGED, JUST HAD THE WRONG MECHANISM

• HE PROPOSED LAMARCKIAN INHERITANCE

• USE AND DISUSE OF ACQUIRED TRAITS

LAMARCKIAN INHERITANCE

• IF AN ORGANISM USED A SPECIFIC TRAIT A LOT, THEN THAT

TRAIT WAS AUTOMATICALLY PASSED ON TO ITS OFFSPRING

• WORKED OPPOSITE AS WELL – IF AN ORGANISM DID NOT

USE A SPECIFIC TRAIT, THEN THAT TRAIT WAS NOT PASSED ON

TO ITS OFFSPRING

• HE USED GIRAFFE’S TO PROVE HIS THEORY

• SINCE THEY KEPT STRETCHING THEIR NECKS TO REACH HIGH

LEAVES, GIRAFFES NECKS BECAME PROGRESSIVELY LONGER

FROM GENERATION TO GENERATION

• DRIVEN BY NEED

LAMARCKIAN INHERITANCE

• IF LARMARCK’S THEORY WAS TRUE THEN

ARNOLD SCHWARZENEGGER WOULD

HAVE PASSED LARGE MUSCLES ON TO HIS

CHILDREN

• RIGHT??????

LAMARCKIAN INHERITANCE

• WRONG!!!!!

• SCHWARZENEGGER’S OFFSPRING

• HIS CHILDREN DID NOT AUTOMATICALLY INHERIT

LARGE MUSCLES JUST BECAUSE THEIR FATHER USED

HIS A LOT

LAMARCKIAN INHERITANCE

• WE CAN TRY TO APPLY THE SAME THEORY TO

SOMEONE WHO IS MISSING A LIMB

• SINCE THIS GIRL IS MISSING AN ARM, ACCORDING

TO LAMARCKIAN INHERITANCE HER CHILDREN

WOULD AUTOMATICALLY NOT HAVE AN ARM….

• AGAIN WRONG!

SO WHO WAS RIGHT?

• OVER TIME LAMARCK’S THEORY WAS PROVEN WRONG

• IT WAS LATER REPLACED BY DARWIN’S THEORY ON NATURAL SELECTION

CHARLES DARWIN

• ENGLISH MINISTER TURNED NATURALIST (1809 – 1882)

• SAILED AROUND THE WORLD IN A SHIP CALLED THE BEAGLE

• CONSIDERED THE “FATHER OF EVOLUTION”

• HE CAME UP THE THEORY OF NATURAL SELECTION THAT IS WIDELY ACCEPTED STILL TODAY

• HE PUBLISHED IT IN HIS BOOK CALLED THE ORIGIN OF SPECIES IN 1859

EVIDENCES OF EVOLUTION

• DARWIN USED THE FOLLOWING EVIDENCES TO PROVE HIS THEORY OF EVOLUTION

• MORPHOLOGIES

• FOSSILS

• EMBRYOLOGY

• COMPARATIVE ANATOMY

MORPHOLOGIES

• THE FORM AND STRUCTURE OF ORGANISM’S TRAITS DEPENDING

ON THEIR ENVIRONMENT

• EXAMPLE:

• FINCHES ON THE ISLANDS OF THE GALAPAGOS HAVE DIFFERENT

BEAK SHAPES FOR THE FUNCTION OF EATING DIFFERENT FOOD

ITEMS AVAILABLE ON THEIR ISLAND.

FOSSILS

• STUDY OF PRESERVED REMNANTS OR IMPRINTS OF ORGANISMS

• TRANSITIONAL FOSSILS

• EXPLAIN LINKS BETWEEN DIFFERENT GROUPS

• EXAMPLES –

• TIKTAALIK IS AN ORGANISM THAT SHOWS US HOW ORGANISMS TRANSITION FROM WATER TO LAND.

• ARCHROPTERYX IS A TRANSITIONAL FOSSIL THAT SHOWS US HOW BIRDS EVOLVED FROM REPTILES.

Tiktaalik

Archeopteryx

FOSSILS

• LAW OF SUPERPOSITION

• STATES THAT RECENT FOSSILS WILL BE FOUND AT THE TOP

LAYERS, WHILE OLDER FOSSILS WILL BE FOUND ON THE

BOTTOM LAYERS

FOSSILS

• SEQUENTIAL TRANSITIONAL FOSSILS

• SHOWS HOW ONE ORGANISM PROGRESSED OVER TIME

FOSSILS

• LIVING FOSSILS (GHOSTS OF EVOLUTION, ANACHRONISMS)

• LAST OF THEIR LINEAGE OR “HOLDOVER” FROM EARLIER TIMES

• EXAMPLES –

• PLATYPUS – THE LAST OF THE MAMMALS TO STILL LAY EGGS

• HORSETAILS AND AVOCADOS – AMONG THE OLDEST PLANTS LIVING TODAY

EMBRYOLOGY

• COMPARING EMBRYOS OF DIFFERENT ORGANISMS FOR

SIMILARITIES SHOWING THE DEVELOPMENTAL PROCESS IS THE

SAME IN DIFFERENT SPECIES

• THIS PROVES THAT CERTAIN ORGANISMS DESCENDED FROM A

COMMON ANCESTOR

• EXAMPLE –

• ALL VERTEBRATES HAVE GILL SLITS AND A TAIL BONE IN THE

EMBRYONIC STAGE. IN SOME ANIMALS THESE TURN INTO

ACTUAL GILLS, IN OTHERS THEY TURN INTO EAR BONES

COMPARATIVE ANATOMY

• COMPARING THE STRUCTURE OF

DIFFERENT ORGANISMS TO SHOW

COMMON ANCESTRY

• TYPES –

• HOMOLOGOUS STRUCTURES

• ANALOGOUS STRUCTURES

• VESTIGIAL STRUCTURES

HOMOLOGOUS STRUCTURES

• SAME STRUCTURE, DIFFERENT FUNCTION

• DUE TO A COMMON ANCESTOR

• CAUSED BY DIVERGENT EVOLUTION

• SPECIES THAT WERE ONCE SIMILAR EVOLVE DIFFERENTLY DUE TO

DIFFERENT ENVIRONMENTS

ANALOGOUS STRUCTURES

• SAME FUNCTION, DIFFERENT STRUCTURE

• DUE TO DIFFERENT ORGANISMS NEEDING THE

SAME FUNCTION

• CAUSED BY CONVERGENT EVOLUTION

• SPECIES THAT WERE ONCE VERY DIFFERENT

EVOLVE TO HAVE SIMILAR TRAITS

VESTIGIAL STRUCTURES

• STRUCTURES PRESENT IN MODERN ORGANISMS THAT

NO LONG FUNCTION, BUT FUNCTIONED IN ANCESTRAL

ORGANISMS

• EXAMPLES IN HUMANS –

• APPENDIX

• WISDOM TEETH

• TAIL BONE

OTHER EVIDENCES OF EVOLUTION

• THE FOLLOWING EVIDENCES HAVE SINCE BEEN ADDED TO DARWIN’S

• BACTERIAL RESISTANCE

• MOLECULAR DATA

• ENDOSYMBIOSIS

• THESE WERE NOT KNOWN IN DARWIN’S TIME BUT DUE TO THE TECHNOLOGY WE HAVE TODAY

WE CAN NOW HELP FURTHER PROVE DARWIN’S THEORY

BACTERIAL RESISTANCE

• AS WE USE ANTIBIOTICS MORE, BACTERIA ARE EVOLVING TO BECOME RESISTANT TO THEM

• THE BACTERIA SURVIVE AND CONTINUE TO MULTIPLY CAUSING US TO BECOME MORE SICK

MOLECULAR DATA (MOLECULAR BIOLOGY)

• FINDING THE RELATIONSHIPS IN THE AMINO ACIDS AND DNA OF DIFFERENT SPECIES TO SEE

HOW SIMILAR OR DIFFERENT THEY ARE FROM EACH OTHER

WHICH PRIMATE IS MOST CLOSELY RELATED TO

THE CHIMP?

• COMPARE THE AMINO ACIDS OF THE CHIMP TO

EACH OF THE OTHER ANIMALS.

• THE ANIMAL WITH THE LEAST AMOUNT OF

DIFFERENCES FROM THE CHIMP WILL BE THE

MOST CLOSELY RELATED

WHICH PRIMATE IS MOST CLOSELY RELATED TO

THE CHIMP?

• GORILLA AND CHIMP HAVE THE SAME AMINO

ACIDS

ENDOSYMBIOSIS

• SMALL BACTERIA CELLS ENTERED LARGER BACTERIA

CELLS. THESE SMALLER CELLS BEGAN TO LIVE INSIDE

AND BENEFIT THEIR HOST CELL, EVENTUALLY

BECOMING CELLULAR ORGANELLES

• EXAMPLES –

• MITOCHONDRIA

• CHLOROPLASTS