a change in a species over time Evolution a change in a species over time

There are many types of evidence that support the theory of evolution 1. Anatomical Evidence: 2. Fossil Evidence: 3. Radioactive dating: 4. Relative Dating: 5. The Fossil Record 6. Embryological Evidence: 7. Chemical Evidence: 8. The Molecular Clock:

1. Anatomical Evidence: The French biologist Lamarck began to look at similar structures in different species. body parts Organs EX: bat’s wing, dolphin’s flipper,

Theory of Use and Disuse   Lamarck that individuals would acquire or lose structures through their use or disuse. EX: giraffe

Problems tailbone Appendix Ex: Another scientist tested this by cutting the tails off mice.

2. Fossil Evidence: Fossils- the imprints or remains of plants or animals that existed in the past

Carbon-14 is the radioactive form of carbon half-life of 5,770 years All living things have carbon-14 when the organism dies its C-14 starts to decay. By measuring how much C-14 is left tell how old the fossil is.

3. Radioactive dating: elements that give off radiation as they decay not all elements decay at the same rate half-life- measuring the decay rate non-radioactive element- the time it takes for ½ of the element to break down  

Example: Carbon-14 is the radioactive form of carbon half-life of 5,770 years. when the organism dies, it decay. By measuring how much C-14 is left in a fossil, you can tell how old the fossil is.

A sample had 100 grams of C-14 50 grams after 5770 years 25 grams = 11,540 years 12.5 grams =17,310 years 6.25 grams = 23,080 years

Theory of evolution so far 5. The Fossil Record 1. Anatomical Evidence: 2. Fossil Evidence: 3. Radioactive dating: 4. Relative Dating:

5. The Fossil Record This includes ALL of the fossil evidence scientists have collected Steno’s drawing of a shark head helped him see that “tongue stones” were actually fossil shark teeth (right).

Example Some fossil bones of a leg and a foot were found in sedimentary rock in the Mississippi River valley. Fossils found in the same layers helped them figure out it was probably the size of a cat, but had other traits of a horse. They named it Eohippus = early horse. Could tell from the bones: 4 toes on each front foot toes were spread apart.

They used radioactive dating To determine the age to be about 50 million years. spread-apart toes would help it to walk on mud Other fossils in those layers : climate was warm and wet possibly a tropical climate surrounded by swamps and mud

                                                         

Scientists put all of this information together to help form a better idea of what an organism looked like, how it lived and how it changed over time

mutations Changes of what organism looked like

ADAPTATION. a change that makes it easier for an organism to survive is animals that could not adapt became extinct.                                One of the most difficult

6. Embryological Evidence: Embryos are developing organisms. Scientists compare the embryos of different species to see how closely related they are.

7. Chemical Evidence: Chemical similarities in the DNA of different species = shows us how they might be related. Ex: The DNA of a zebra and a quagga

8. The Molecular Clock: The more similar the structure of protein molecules between 2 organisms, the more recent their common ancestor. Scientists developed a time scale how long it takes proteins to change over time They use this to figure out how long ago a protein changed.

http://www. ucmp. berkeley http://www.ucmp.berkeley.edu/education/explorations/tours/geotime/gtpage5.html http://www.ucmp.berkeley.edu/education/explorations/tours/geotime/clonus/transparent.gif

Now let's make a similar timeline for some of the major events during the history of life on Earth. Here are pictures of some fossils. Your goal is to put them into the correct order of when they first appeared on Earth. Just click on the fossils in order, from the earliest to the most recent. Ooops! Remember to start with the earliest event first!   Try again. Great! You have created another timeline! But how did we know the order this time? In the U.S. history timeline, records were kept of the events as they happened; so it was easy to use this evidence and put them in order. But with these events in the history of Earth, we don't have such a clear record of the order or the dates.... or do we?

http://www. ucmp. berkeley http://www.ucmp.berkeley.edu/education/explorations/tours/geotime/clonus/transparent.gif

Theory of evolution 1. Anatomical Evidence: 2. Fossil Evidence: 3. Radioactive dating: 4. Relative Dating: 5. The Fossil Record 6. Embryological Evidence: 7. Chemical Evidence: 8. The Molecular Clock: