Evidence supporting Evolution

 Six main lines of evidence that supports the theory of evolution 1.Fossil Evidence 2.Homologous Structures 3.Vestigial Structures 4.Embryology 5.Biochemical Evidence

Fossils Formation  How Fossils Form i.Fossils can be very large complete skeletons, or very small items such as a tooth ii.Most fossils form in sedimentary rock iii.The formation of fossils only occurs under certain conditions & therefore the fossil record is an incomplete record of life & evolution

Fossil of a fish: perch Fossil Record

Water carries small rock particles to lakes and seas. Dead organisms are buried by layers of sediment, which forms new rock. The preserved remains may later be discovered and studied. Formation of a Fossil

 Fossil Record & Evolution i.It shows how different groups of organisms have changed over time ii.Similarities between fossils and existing organisms suggests that certain groups of organisms have common ancestors. iii.The fossil record shows missing links/ intermediated organisms between groups of organisms iv.99% of all living things that have lived on the Earth are now extinct

Fossils & Evolution: 99% of all living things that have lived on the Earth are now extinct i. Organisms that went Extinct oExample: Ammonite

Fossils & Evolution: 99% of all living things that have lived on the Earth are now extinct o Example: Dinosaur tracks

ii.The fossil record shows us how animals have changed over time o Examples: Skulls of Australopithecus and Homo erectus Fossils show us how organism have Changed over time

The fossil record shows us how organisms have changed over time & Missing links between groups of organisms o Examples: Fossils of Skeletons of horse ancestors shows the evolution of the modern horse

Fossils of Skeletons of horse ancestors shows the evolution of the modern horse The fossil record shows us how organisms have changed over time & Missing links between groups of organisms

Homologous Structures Traits that are similar in different species, share a common ancestor Examples: arm in a human, flipper a seal, wing of a bat all have the same bone structures, but serve different functions The species evolved from a common ancestor & adapted to a different environment Different environments had different natural selection pressures so overtime structures would have changed to better suit an organism environment.

The bones in a bat's wing, human's arm, penguin's flipper are the same (homologous), but the function is different

What can we conclude from similarities in bone Structure? These organism evolved from a Common Ancestor that moved into different environments & thus had different natural selection pressures.

Vestigial Structures Structures that are inherited but no longer used by the organism They are ancestrial remnants that once had a purpose, but now have no functional pupose Example: Small hind leg bones (pelvis & femur) of a whale

Vestigial Structures Example: Small hind leg bones (pelvis & femur) of a whale Whales evolved from a 4 legged pig- like animal. Thus whales still have hind leg bones which no longer function

Example: Human appendix has no functional purpose, but our herbivore ancestors used it to help them digest plant material

Embryology Evidence Vertebrates embryos pass through a series of similar stages in early development.

Human Chicken Pig

Human Chicken Pig Evolutionary history can be seen in early development of vertebrate animals

Biochemical Evidence of Evolution Similarities between living things: All use the DNA molecule as their genetic material All use the same 20 amino acids molecules in their proteins All use ATP molecule to store chemical energy. All do similar cellular respiration to access energy from food (chemical energy)

Biochemical Evidence DNA Evidence Comparing DNA sequences between living organism show close similarities between organisms of different species.

Biochemical Evidence Example: Humans and chimpanzees have % identical DNA sequence This suggests a recent common ancestor.

Biochemical Evidence ALL LIVING THINGS USE DNA Similarities between living things: All use DNA molecule as their genetic material Suggesting common ancestry.

Biochemical Evidence All proteins in living things are made of the same 20 amino Similarities between living things: All use the same 20 amino acids molecules in their proteins Suggesting common ancestry.

Biochemical Evidence Similar Proteins in all vertebrates All vertebrates, including fish, reptiles, amphibians, birds, mammals use the protein hemoglobin to transport oxygen in blood. Suggesting common ancestry.

Biochemical Evidence Similarities between living things: All use left, and not right-handed amino acids Suggesting common ancestry.

Biochemical Evidence ATP All living things use the molecule Adenine Triphosphate for energy. Suggesting common ancestry.