1. Exciting Evolution
Chapter 22

2. I. Science as a Process
Linnaeus ( ) – specialized in Taxonomy – naming and classifying organisms. Grouped similar species into categories showing relationships
Developed binomial (two part) naming according to genus and species (i.e. Homo sapiens)

3. Science as a Process
Kingdom-Phylum-Class-Order-Family-Genus-Species

4. Early Theories of Change To Explain the fossil record
Catastrophism – each boundary between strata corresponded in time to a catastrophe (flood/drought etc) that destroyed many species living at the time. Other species moved to these areas from surrounding areas.

5. Early Theories of Change To Explain the fossil record
Gradualism – profound change is the cumulative product of slow but continual processes (canyons formed by rivers cutting through rocks

6. Science as a Process
Uniformitarianism – geologic processes have not changed throughout Earth’s history (ex. forces that build mtns and erode mtns are the same now as in the past)

7. C. First Evolution Hypothesis
Jean Baptiste Lamarck –published his theory of evolution in 1809
Use and Disuse – those parts of the body used extensively to cope with the environment becomes larger and stronger while those not used deteriorate
Inheritance of Acquired Characteristics – modifications an organism acquires during its lifetime can be passed along to its offspring.

8. II. Darwin’s Descent with Modification
Conclusions
Earth must be old ( years)
Slow and subtle processes over long periods of time can add up to substantial change

9. Darwin (cont)
Unity of life – all organisms are related through descent from some unknown ancestor that lived in the remote past. As the descendents moved into various habitats over millions of years, they accumulated diverse adaptations that helped them survive in their environment

11. Darwin’s Observations
Members of a population often vary greatly in their traits
Traits are inherited from parents to offspring
All species are capable of producing more offspring than their environment can support
Due to lack of food or other resources, many offspring do not survive

12. Inference 1
Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals

13. Inference 2
This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations

14. Natural Selection
A process where individuals that have certain heritable characteristics survive and reproduce at a higher rate than other individuals.
Over time, natural selection can increase the match between organisms and their environment
If an environment changes, or if individuals move to a new environment, natural selection may result in adaptation to these conditions

15. Evolution
Change in the genetic composition of the population over time
Individuals cannot evolve, only a population of interbreeding individuals
Only heritable traits can be amplified by natural selection (not traits acquired in lifetime – like big muscles)

16. Examples of natural selection
Galapagos finches – beaks different depending on food source
Antibiotic resistance of bacteria
Insecticide resistance in insects
Drug Resistant HIV (due to differences in reverse transcriptase enzymes)

18. III. Other Evidences of Evolution
Homology – similarities in characteristics resulting from common ancestry
Anatomical Homologies – similar structures in organisms with similar ancestry (bones in human arm, cat paw, whale flipper, bat wing)
*vestigial organs- structures of little or no importance to an organism (like our appendix) – may have had a job in ancestor

20. A. Homology
Embryological Homologies- similarities in embryonic development
ex. all vertebrate embryos have pharyngeal pouches
Molecular Homologies – certain characteristics are shared by all organisms at the molecular level
DNA and RNA – universal genetic code
Many similar proteins

22. B. Biogeography geographic distribution of species
Species tend to be more closely related to other species from the same area than to other species with the same way of life but living in different areas
Islands are a perfect example of biogeographical evidence of evolution
ex. finches in Galapagos, honeycreepers and fruit flies in Hawaii

24. C. Fossil Record
Prokaryotes are thought to be the earliest organisms, and the oldest known fossils are prokaryotes.
Vertebrates appear in the fossil record as they are believed to have evolved
Fish – amphibians – reptiles – mammals and birds

28. Convergent Evolution
Independent evolution of similar features in different lineages
Develop similar characteristics due to living in similar environments
ex. Sugar glider (marsupial) and flying squirrel (placental mammal)