1. EVOLUTION: Part 1: The Fossil Record
Evolution = (change in # of alleles in a population) / time
Evolution = descent with modification

2. Archeopteryx - a transitional fossil between non-avian dinosaurs and birds

3. T/F Original tissues can be preserved as fossils
Organisms become extinct only in mass extinction events
Environmental change causes variation in populations
Variations can lead to adaptations
Living species contain no evidence that they are related to each other
Plants and animals share similar genes

4. What can be learned from Fossils?
When did this organism live?
How did it move or grow?
How did this organism die?
To what other organisms is this organism related?

5. The Fossil Record
= all the fossils discovered on Earth (millions of species representing thousands of species)
INCOMPLETE – the record only represents a small fraction of all the organisms that have lived on Earth

6. Fossil Formation
Tissue: similar cells that work together and perform a function.
Tissues that are not eaten eventually get broken down by bacteria.
Only the bones, shells, and teeth remain.
Under rare conditions, they become fossils.
Fossils of tissues are EXTREMELY rare.

7. Fossil Formation
Mineralization – minerals in the water replace organism’s original material (bones, maybe tissue, fossilized wood).
Carbonization – compression squeezes out liquids and gases, leaving only carbon.
Molds and Casts – mold = impression of an organism (in mud or sand), tiny rocks fill in to form a cast = fossil copy of an organism in a rock
Trace Fossils – preserved evidence of the activity of an organism (footprints, for example) (How did it move or grow?)
Original Material - most are less than 10,000 years old (mammoths frozen in ice), though dinosaur tissues and insects stuck in amber have been found

8. Determining a Fossil’s Age
Relative-Age Dating - the science of determining the relative order of past events (i.e., the age of an object in comparison to another)
Absolute-Age Dating - provides a numerical age or range in contrast with relative dating

9. Relative-Age Dating
The relative order in which rock layers were deposited (added to the location by water, wind, etc.).
The bottom layers are the oldest, the top layers are the youngest.

10. Absolute-Age Dating More precise than relative-age dating.
Determines age by examining radioactive decay in rocks (a natural, clocklike cycle of equilibrium in rocks)
Radioactive decay results in higher and higher ratios of one type of chemical material to another
The older the rock, the higher the ratio.

11. Geologic Time Scale
used by geologists, paleontologists, and other Earth scientists to describe the timing and relationships of events that have occurred during Earth's history
radiometric dating indicates that Earth is about 4.54 billion years old.
Different spans - marked by major geological or paleontological events, such as mass extinctions.

12. GEOLOGIC TIME SCALE

13. Earth’s History in 24 hours
The Earth is 4.54 billion years old (if the average person lives 75 years, that would be over 60 million lifetimes!)

14. Colorado and Fossils Green River Formation Picketwire Canyonlands
Fossil Lake
Fossil Beds

15. Eons Primary defined divisions of geologic time
Hadean (4.6 – 4.0 bya) – Earth just formed, very hot
Archean (4.0 – 2.5 bya) – prokaryotic cells appear
Proterozoic ( bya) – eukaryotic cells appear (yum!)
Phanerozoic (.5 bya – now) - animal and plant life

16. Extinction = the termination of a species.
> 99 % of all species (over five billion species)
can’t survive/reproduce in the environment or move? You’ll go extinct.
Viruses and bacteria

17. SOME Causes of Extinction
Climate change
Competition
Disease
Habitat Degradation

18. Extinction Events (due to major changes on Earth)
at least five mass extinctions in the history of life on earth, and four in the last 350 million years in which many species have disappeared in a relatively short period of geological time.
% of species that became extinct

19. The Holocene Extinction
due to human activity
Many species, everywhere
Habitat destruction (lots undocumented)
100 to 1,000 x higher than natural rates.

20. Positives? new opportunities for surviving species
Mammals, for example

21. Decline of Amphibians
frogs and toads, newts and salamanders, caecilians
1/3 to ½ are threatened with extinction
Due to humans AND disease

22. De-extinction Resurrection of a species Cloning and selective breeding

23. Vocab
Population - all the organisms of the same group or species, which live in a particular geographical area, and have the capability of having offspring.

24. Population variability
to succeed over evolutionary time, a population must contain genetic variability.
Random mutation – the source of genetic variation
Lots of variation
Little variation 

25. The Peppered Moth dark or light colored
before Industrial revolution, the light-colored allele was most prevalent.
white-barked trees
Stained by Pollution
dark-colored allele became most dominant

26. Mutation beneficial, harmful, or neutral (fitness) Migration
Advantages -> selection

27. Charles Darwin

28. Galapagos Finches (a few million years in the making)
niches
15 recognized species differing in body size, beak shape, song and feeding behavior
adaptive radiation = rapid

29. Darwin’s Theory of Natural Selection
More individuals are produced each generation that can survive.
Phenotypic variation exists among individuals and the variation is heritable.
Those individuals with heritable traits better suited to the environment will survive.
When reproductive isolation occurs new species will form.
Artificial, too…

30. Quote by Darwin
"Variation is a feature of natural populations and every population produces more progeny (offspring) than its environment can manage. The consequences of this overproduction is that those individuals with the best genetic fitness for the environment will produce offspring that can more successfully compete in that environment. Thus the subsequent generation will have a higher representation of these offspring and the population will have evolved."