1. Fossils and evolution part ii
Bell Question: What, in your own words, is biological evolution?

2. Finish Fossil Lab

3. Copy this diagram in your notebook!
Fossils
Preserved fossils
Rock Fossils
amber
tar
ice
Trace fossils
Casts and molds
Petrified fossils
Carbon films

4. Fossil Dating Relative and Chronometric Dating
Relative dates give the time of an event with reference to another event that is not worldwide in scale. They tell us simply that one thing is older or younger than another
Chronometric dates place events in their chronological position with reference to a universal time scale such as a calendar.

5. Relative Dating
For example, in comparing the cross-section of the series of geological strata illustrated above, level C is older than B because it is below it. This does not tell us how many years ago these strata were laid down. It only tells us how old each is relative to the others

6. Relative Dating cont.
However, geological strata are not always found to be in a neat chronological order. Wind and water erode strata and some areas are uplifted or even tilted. These processes result in unconformities, or breaks in the original stratigraphic sequence. In addition, people and other animals often dig holes, resulting in a mixing of material from different strata (as shown below)

7. Relative Dating cont.
Index Fossils When the bones of our early ancestors are found in the same geological strata as those of other animals that are known to have lived only during a specific time period in the past, we assume that these ancestors must also have come from that time.
Fluorine Analysis When bones, teeth, or antlers are found at a site, fluorine analysis can be used to tell us whether or not the animals they were from actually lived at about the same time. This relative dating method is based on the fact that there are specific progressive chemical changes in skeletal remains that result from burial underground.

8. Chronometric Dating
Dendrochronology is one of the most reliable chronometric dating techniques and is based on the fact that annual growth rings on shallow rooted trees vary in width with the amount of water available each season and with temperature fluctuations from winter to summer.

9. Chronometric Dating cont.
Geomagnetic Reversal Time Scale is based on major periodic changes in the Earth's magnetic field. Datable materials include volcanic rock, fired clay pots, and other forms of clay or rock that have been exposed to high temperatures.

10. Chronometric Dating cont.
Radioactive Decay
Certain naturally occurring elements are radioactive, and they decay, or break down, at predictable rates.
Chemists measure the half-life of such elements, i.e., the time it takes for half of the radioactive parent element to break down to the stable daughter element. Sometimes, one isotope, or naturally occurring form, of an element decays into another, more stable form of the same element.
By comparing the proportions of parent to daughter element in a rock sample, and knowing the half-life, the age can be calculated.

11. Theory of evolution by natural selection
The theory of evolution by natural selection, first formulated in Darwin's book "On the Origin of Species" in 1859, is the process by which organisms change over time as a result of changes in heritable physical or behavioral traits.
Extinction is the end of an organism or of a group of organisms, normally a species. 

12. Definitions
Morphology is the form of living organisms and the relationships between their structures.
Fossil is the evidence (usually in sedimentary rock) of the presence of a plant or an animal from an earlier geological period.
Phylogenetic trees are used to relate the evolutionary development and diversification of a species or group of organisms.

13. Evolution
Evolutionary equilibrium is a theory in evolutionary biology which proposes that once species appear in the fossil record they will become stable, showing little evolutionary change for most of their geological history. This state is called stasis.
Evolutionary gradualism is a model of evolution which theorizes that most speciation is slow, uniform and gradual. When evolution occurs in this mode, it is usually by the steady transformation of a whole species into a new one

14. Speciation
Divergent speciation is the process by which a species evolves into two or more descendant or different forms; also, the process of tracing two or more species back to a common ancestor.
Phyletic speciation is the process of gradual change in a single population.

15. Phylogenetic tree (Basic)

16. Phylogenetic tree (Complex)

17. Human Phylogenetic Tree
According to the fossil record:
Hominins emerged about 6 million years ago.
Early humans emerged about 200,000 years ago.

19. Is this our fate?

20. Or do we evolve further?

21. What is the Evidence of evolution?
Evolution Video

22. In class Assignment
In a paragraph and in your own words, write the reason(s) you think humans will or will not evolve further.
Be prepared to share your thoughts with the rest of the class!!!