WHAT IS THE EVIDENCE THAT all life evolved from A common ancestor?

Life has evolved from simple to complex over billions of years…

How do we know?

FOSSILS!

Now almost all living things die without even leaving a fossil trace of their existence. DECOMPOSITION, EROSION, WEATHERING, PREDATION

Still, we do find them if we are lucky & look carefully enough.

FOSSILS MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened.

FOSSILS! MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in with sediment & hardens leaving a 3-D shape of that organism.

FOSSILS! MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in & hardens leaving a 3-D shape of that organism. PRESERVED REMAINS—when an organism or its parts have NOT DECAYED by being trapped in tar, ice, amber, etc. DNA possible!

FOSSILS…are you writing these down? MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in by sediments & hardens leaving a 3-D shape of that organism. PRESERVED REMAINS—when an organism or its parts have NOT DECAYED by being trapped in tar, ice, amber, etc. DNA possible. PETRIFIED FOSSILS—when minerals replace the remains of a buried organism, changing them into hard rock. not soft sediment

FOSSILS…are you writing these down? MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in by sediments & hardens leaving a 3-D shape of that organism. PRESERVED FOSSILS—when an organism or its parts have NOT DECAYED by being trapped in tar, ice, amber, etc. PETRIFIED FOSSILS—when minerals replace the remains of a buried organism, changing them into hard rock.

FOSSILS! MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in by sediments & hardens leaving a 3-D shape of that organism. PRESERVED FOSSILS—when an organism or its parts have NOT DECAYED by being trapped in tar, ice, amber, etc. DNA PETRIFIED FOSSILS—when minerals replace the remains of a buried organism, changing them into hard rock. CARBONIZED FOSSIL—when organisms are squeezed between layers, decay and leave dark carbon imprints in the rock.

FOSSILS! MOLD FOSSILS—organism decayed in sediment leaving an impression of what it looked like as sediment hardened. CAST FOSSILS—when the mold fills in by sediments & hardens leaving a 3-D shape of that organism. PRESERVED FOSSILS—when an organism or its parts have NOT DECAYED by being trapped in tar, ice, amber, etc. PETRIFIED FOSSILS—when minerals replace the remains of a buried organism, changing them into hard rock. CARBONIZED FOSSIL—when organisms are squeezed between layers, decay and leave carbon imprints in the rock. TRACE FOSSILS—when mud or sands harden where a footprint, trail, or any evidence of an organism was left behind.

CHECK for UNDERSTANDING Can you spot the layer with trace fossils?

CHECK for UNDERSTANDING Can you spot the layer with trace fossils? 9 Did boney fish evolve before or after trilobytes?

Trilobyte…

CHECK for UNDERSTANDING Can you spot the layer with trace fossils? 9 Did boney fish evolve before or after trilobytes?

CHECK for UNDERSTANDING Can you spot the layer with trace fossils? 9 Did boney fish evolve before or after trilobytes? What evidence do we have here that mammals evolved after dinosaurs?

CHECK for UNDERSTANDING Can you spot the layer with trace fossils? 9 Did boney fish evolve before or after trilobytes? What evidence do we have here that mammals evolved after dinosaurs? Mammal jawbones above dinosaur footprints.

WHAT DOES bio-EVOLUTION mean? what slowly changes over time…

BIO-EVOLUTION--The way a species slowly change into other species over a long, long time…

…through NATURAL SELECTION—Survival of the FITTEST! BIO-EVOLUTION--The way a species slowly change into other species over a long, long time… …through NATURAL SELECTION—Survival of the FITTEST!

Evidence that life EVOLVES from earlier species: TRANSITIONAL FOSSILS

Evidence that life EVOLVES from earlier species! FOSSILS

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—show how new species evolved from previous species over many, many generations

Look at how human-like skulls have shown evolution over the last million years! Transition fossils…

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES

Evidence that life EVOLVES from an earlier species (common ancestor):: TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—similar among ALL living things

Cells in all EUKARYOTIC living things pretty much have the same organelles. TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—are similar among living things

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—are similar among ALL living things DNA— http://genetics.thetech.org/online-exhibits/genes-common show mag cover…

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—are similar among ALL living things DNA— http://genetics.thetech.org/online-exhibits/genes-common show mag cover…

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—are similar among ALL living things DNA— http://genetics.thetech.org/online-exhibits/genes-common show mag cover…

Evidence that life EVOLVES from an earlier species (common ancestor): TRANSITIONAL FOSSILS—shows slow gradual change of a species over a LONG time! CELL STRUCTURES—are similar among ALL living things DNA—the more DNA we share with another species, the closer we are related. http://genetics.thetech.org/online-exhibits/genes-common

Using DNA we can make a TREE of LIFE! Geneticists have compared the DNA of almost all living things and made a tree showing how we are all genetically related!

Look at this phylogenic tree Look at this phylogenic tree. According to our DNA, are whales more closely related to us or sharks?

Look at this phylogenic tree Look at this phylogenic tree. According to our DNA, who are birds more closely related to?

According to this phylogenic tree, are dogs more closely related to seals or cats?

Go to part 2