1. A. Geologic time—Earth’s history is divided into time units that make up a geologic time scale. 1. Units on the scale are based on appearance/disappearance of organisms such as trilobites, index fossils that lived in specific time periods B. Four major divisions of Geologic Time. 1. Eons—longest subdivision; based on abundance of fossils 2. Eras—marked by significant worldwide changes in the types of fossils present in rock 3. Periods—based on types of life existing worldwide at a particular time 4. Epochs—characterized by differences in life-forms, but differences can be regional rather than global

2. Pre-Cambrian Time -Lasted from 4.5 billion years ag0 until 544 million years ago -Few Life forms existed at this time - Single cell organisms, such as CYANOBACTERIA dominated -Invertebrates appeared during this time (similar to jellyfish and corals), left trace fossils -Major geologic events: Earth was cooling -“Cambrian” explosion- rapid spread of inverts marked the end of the Pre- Cambrian

3. Cyanobacteria Grow in mats called stromatolites These photosynthetic bacteria created much of the oxygen in the early atmosphere

4. Paleozoic Era -544 million to 248 million years ago -Dominated by invertebrates that lived in oceans (lots of shelled animals) -First land plants /animals and vertebrates (fish, reptiles, and amphibians) appear -Several mountain building events, including the building of the Appalachian Mountains occurred in this era; creation of PANGAEA -Ended with a mass extinction (cause still debated)

5. What characteristics of reptiles, allowed them to be the first animals to move away from the water? Protective scaly skin, eggs that could be laid away from water, claws for digging and climbing

6. Mesozoic Era -248- 65 Million years ago -“Age of the Dinosaurs”- dominated by reptiles -Birds, Mammals, and Flowering plants appear in this era -Major Geologic Events: break- up of Pangaea and eventual formation of current continents -Ended with a mass extinction, possibly caused by a comet or meteor striking the Earth

7. Who survived? What organisms survived the mass extinction of 65 million years ago?

8. Cenozoic Era -65 million years ago until today -Dominated by mammals -Humans first appear during this time -The Alps, Andes and Himalayan mountains formed

9. C. Organic evolution—Organisms have changed over time, most likely because of environmental changes. D. Species—organisms that normally reproduce only with other members of their group E. Darwin’s theory of natural selection—organisms more adapted to an environment are more likely to reproduce  1. Natural selection within a species occurs only if characteristics present in some numbers increase their survival.  2. Artificial selection—breeding individuals with desired characteristics; humans use this type of selection when breeding domestic animals.  3. New species can evolve from natural selection.

10. Species a group of organisms that normally reproduces only with other members of their group. 2 members of the same species – fertile offspring 2 different species – non fertile offspring Ex: 2 dogs Ex: a lion and a tiger Even though 2 organisms look nearly alike, if the populations they each come from do not interbreed naturally and produce offspring that can reproduce, the 2 individuals do not belong in the same species!

12. Natural Selection Activity 1.Create a table on your paper that looks like the one above. 2.Lay the dark green piece of paper on your table. 3.Pour the tiny pieces of paper from the envelope onto the green paper. 4.You will have 15 seconds to pick up as many of those pieces of paper as you can and place off to the side of the green paper. 5.Count how many of each color is left on the paper and record it in the table. 6.Repeat same process with your partner. Dark GreenLight GreenYellowRedBlue Name Person 1 Name Person 2

13. 1.What color did you have the most of left? 2.Why do you think that you had the most of that color???

14. Natural Selection - Charles Darwin – published a book – theory of evolution by natural selection - is a process by which organisms with characteristics that are suited to a certain environment have a better chance of surviving and reproducing than organisms that do not have these characteristics. - organisms compete with each other for resources necessary for life (ex: food, living space) - differences could hurt or help an organism stay alive (these are called adaptations)

16. “Survival of the fittest.” better adapted – live longer, better chance of producing offspring less adapted – shorter life, less chance of producing offspring So, the better adapted genes are passed on more often. According to Darwin, this cause species to change over time.

17. Short neck giraffe (rare) Long neck giraffe (common) Amount of short neck giraffes has decreased over time.

18. Artificial Selection - used by humans to breed animals - carefully choosing individuals with desired characteristics - Can you name three breeds of dog?

19. Bellwork 10/7/10 Answer in complete sentences- to be turned in: 1. What characteristics of reptiles, allowed them to be the first animals to move away from the water? 2. How would life be different today if cyanobacteria had not produced oxygen for Earth's atmosphere? 3. Explain why mammals could not be dominant until the Cenozoic era?

20. F. Plate Tectonics- Continental collisions formed the giant landmass Pangaea near the end of the Paleozoic Era. These collisions may have dropped sea levels - May have caused extinction of Trilobites

21. Movement of the Continents Lightly color landmasses these colors on both maps: -North America- Purple - South America- Red -Europe/ Asia- Green - India- Yellow -Africa- Orange - Australia- Brown