1. Evolution

2. Do Now: View the finches. What characteristics do they have in common?
What can you infer from these similarities?
What characteristics are different?
Why do you think they evolved these differences?
Common – head shape, beaks, feathers, general coloring, “ears” etc – indicates they are related
Differences – some have different coloring on chest, beaks are different, different sizes – beaks are due to diet, coloring for camoflauge, size to fit into different spaces or to get food

3. Charles Darwin (1809 – 1882) British Naturalist
5 year voyage of HMS Beagle around the world
Credited with the theory of natural selection
Began voyage at 22 yrs old

4. Darwin’s Influences Erasmus Darwin
All life was “produced by a simple life filament”
Organisms change over time
Jean Baptiste Lamarck
Inheritance of acquired characteristics
Law of use and disuse
Discredited with the discovery of genes
Charles Lyell
Principles of Geology – the present is the key to the past
Thomas Malthus
“Essay on the principle of population”
Population – a group of individuals that belong to the same species, live in a defined area, and breed with others in the group
Populations have the potential to increase faster than the available food supply…but this doesn’t occur because of death by disease, war, and famine
Erasmus – uncle…simple life filament is prob DNA
Lamarck – thought acquired characteristics could be inherited – like if you dye your hair…that theory was discredited when we discovered genes. Use & disuse – what is used gets stronger, what is not used gets smaller & weaker
Lyell – study the present to learn about the past – he applied this to the history of the Earth, Darwin applied it to living things

5. Facts About Evolution It is a Scientific Theory (just as Gravity is)
A vast majority of scientists accept it
It is supported by a large body of evidence
There is no scientific evidence contradicting evolution

6. General Knowledge: Selective Breeding
Selective Breeding aka Artificial Selection
Farmers and/or breeders mate plants or animals with desirable genetic traits to produce offspring with desired traits
Inbreeding
Examples:
Dog Breeding
Horse Breeding
Any domesticated plant or animal

7. Darwin’s Observations
Found fossils of extinct armadillos
Plants and animals of Galapagos islands are similar to those in Ecuador
Conclusion: species migrated from S. America to islands and changed after they arrived – “descent with modification”
Galapogos are young islands that developed from volcanoes – they have not been there since the beginning of time. Darwin travelled first to S. America – then to Galapagos…Saw similar species…theorized that that, since the islands were young, the species on them came from Ecuador, migrated, and then changed – called this descent with modification – the species descended from those on Ecuador, and then were modified once they relocated

9. Darwin’s Theory of Evolution by Natural Selection (1844)
Natural Selection: individuals that posses superior physical or behavioral attributes are more likely to survive, reproduce, and pass on the favorable traits to the offspring
Overpopulation
Variation among species
Competition for resources
Successful reproduction
Adaptation – the changing of a species in response to its environment
Overpop- populations tend to create more offspring than can survive to reproduction age. The ones that survive are the best suited to their surroundings. Variation – individuals vary…and these traits may affect survival and reproduction. Competition for resources – individuals compete for resources, and some will be better equipped to get those resources and survive. Successful repro-passes favorable traits on to next generation. Those with favorable traits are more likely to successfully reproduce

10. Controversy over evolution
Lamarck and other’s ideas of change over time severely criticized by church and government
Alfred Wallace develops same theory (1858)
Darwin publishes book in 1859: On the Origin of Species by Means of Natural Selection
People outraged with the idea of being related to apes
Darwin’s theory and evidence (and more recent evidence) were so compelling they became widely accepted by the scientific community
Drwin did not publish for several years after his trip, because he knew it would be controversial – only published once it was developed independently by Wallace.

11. Darwin’s Ideas have been Updated
Microevolution: change occurring within a species over time
Natural Selection causes the frequency of certain genes within a population to change over time
Isolation leads to species formation
Populations of the same species living in different locations tend to evolve in different directions
Isolation – 2 populations of the same species are separated from one another
When individuals of the 2 populations can no longer interbreed, they are considered to be different species
Extinction leads to species replacement
Extinct – species permanently disappears usually due to a change in environment
Species that are better suited to the new conditions may replace those that have become extinct
Macroevolution – change creating a new species over time
Micro – a change in the # of alleles in a population (blue eye gene vs. brown eye gene – if brown eyes helped us survive, the number of brown eye genes in the popluation would increase, and the number of blue eye genes would decrease)
Macroevolution – when new species develop

12. Geographic Isolation and Evolution
Members of the original species migrated to different areas…one area perhaps had trees, and the other did not. The Tree Finches had to adapt to get insects from the trees. The Ground finches adapted to be able to open seeds. Note the beaks.

13. Evolution of Antibiotic Resistance
After treatment with antibiotics
The bacteria have EVOLVED to become more resistant (more of the population is resistant). This occurred through NATURAL SELECTION (the ones more equipped to survive the antibiotic treatment were able to reproduce successfully)

14. Evidence of Macroevolution
Fossils
Change over time can be observed in the fossil record
Darwin predicted that “missing links” would eventually be found, and many were!
1990’s fossils linked whales to land mammals

15. Whale Evolution
If you compare top & bottom, hard to see relationship. If you compare step by step, easier to see. Look at whale (bottom) – still has bones for hindlimb, although the limb does not exist in the whale.

16. Horse Evolution

17. Radiometric Dating of Fossils
Radioactive isotopes decay at a constant rate called a half life
Different isotopes have different half lives
Ex. C-14  N-14 5,730 years
U-238  Pb billion years

18. Calculation Half-Lives
If this chart represents K-40 which has a half life of 1.3 billion years, how old is a sample that contains 25% of its original K-40?

19. Evidence of Macroevolution
Anatomy
Homologous structures: similar structures though functions may vary
Ex. Human arm, bat wing, alligator arm, and penguin arm
Analogous structures: different structure, but similar functions
Ex. Butterfly wings and bird wings
Vestigial Structures: structures that are present but reduced in size or nonfunctional as compared to related organisms
Ex. Coccyx, appendix, ear muscles, wings on flightless birds

20. Homologous Structures

21. Analogous Structures
Analogous structures evolve separately in different organisms in order for them to adapt to common functions
Vestigial structures – getting smaller due to lack of use

22. Evidence of Macroevolution
Biochemical Evidence
The species characteristics change as a result of changes in DNA, ultimately as a result of mutations
Therefore changes in DNA should accumulate over time as species become more different
Compare amino acid sequences to test relativity
The molecular record has shown the same relationships indicated by the fossil record
If species are related, their DNA would be similar, and since DNA codes for amino acids/proteins, the related species would have similar protein structures. When fossils are compared, they do indeed have similar protein structures

23. Evidence of Macroevolution
Embryonic Development
Vertebrate embryos develop similarly
Suggests that development evolved as new genetic instructions were layered on top of older ones
Tail, limb buds, pharyngeal pouches
In fish, pharyngeal pouches develop into gills. Mammalian pharyngeal pouches do not develop into gills, but rather give rise to structures that evolved from gills, such as the eustachian tube, middle ear, tonsils, parathyroid, and thymus (Kardong 2002, pp. 52, 504, 581). The arches between the gills, called branchial arches, were present in jawless fish and some of these branchial arches later evolved into the bones of the jaw, and, eventually, into the bones of the inner ear..In a cat vs human embryo, they both have tails – in humans, it gets absorbed as the embryo develops and becomes the coccyx

24. Embryonic Evidence of Evolution
New ‘directions’ are carried out over the old ‘directions”. SO – embryos develop similarly at first, then the new directions begin to be carried out, resulting in the differences in embryonic development

25. Do Now - Journal
What does “FITTEST” mean – as in “survival of the fittest”?
Does an individual’s ability or desire to reproduce make it less fit?

26. What did Darwin mean?
The term ‘survival of the fittest’ was first coined by Herbert Spencer, not Darwin
Darwin did begin using the term to replace “natural selection”, but not until the 5th edition of Origin of Species
He did not mean strongest, as is sometimes assumed. Any individual that successfully reproduces is contributing to the survival of its species. Therefore, the term “fit” can be considered synonymous with “able to reproduce”

27. Patterns of Evolution Does evolution occur gradually or in spurts?
Gradualism: Change generally occurs over long periods of time
Punctuated Equilibrium: periods of little or no change are interrupted by periods of rapid change
Biologists disagree, however fossil evidence provides evidence for both!
Gaps in fossil record
Sudden disappearance of some organisms
Some organisms unchanged for long periods of time
Some organisms changed gradually

28. Phylogenic Tree
Phylogenic Tree – shows how organism are related through evolution
Each fork in the tree represents a common ancestor

29. Examples of Microevolution
Industrial Melanism: the darkening of populations of organisms over time in response to pollution
Ex. European peppered moth Biston betularia
Dark variety rare until 1850, by 1950 most populations dark
Kettlewell tested to see if natural selection caused changes
Sickle cell Anemia
Sickle Cell is advantageous in central Africa where sickle cell individuals resist malaria
Antibiotic Resistance of bacteria
Mutation provides resistance and easily gets passed to future generations

30. Patterns of Microevolution
Directional Selection: selects for one extreme trait
Ex. Where malaria is not present, sickle cell allele is selected against
Balancing (stabilizing) Selection: selects for intermediate trait
Ex. Human birth weight – too small is too weak and too large provides complications during birth, therefore an intermediate size is selected for
Disruptive Selection: both extremes are selected for
Ex. Shell Color – light shells blend in with the sand, and dark shells blend in with rocks

31. Speciation
Speciation: the process by which a new species forms; over time separate populations of the same species become very different from one another
Divergence: the accumulation of differences between groups
Ecological Races: populations of the same species that differ genetically because of adaptations to different living conditions, but not different enough to be considered different species
Ecological races may continue to diverge until they can no longer reproduce…forming a new species
Maintaining a species
Reproductive isolation: the prevention of mating between formerly interbreeding groups
Geographical
Ecological
Temporal
Behavioral
Mechanical
Reproductive failure
Geo – separated by river, mountains
Eco – occupy different habitats in same area
Temporal – Mate at diff times of day or year
Behav – Different mating rituals that other species ignore’
Mech – One group may not have body parts needed to deliver sperm, for ex
Repro Failure – fertilization will not occur between different species

32. Microevolution leads to Macroevolution
As changes continue to accumulate over time, living species may become very different from their ancestors and from other species that evolved from a common ancestor
Biologists agree that changes within a species eventually lead to the appearance of a new species

33. Do you think…
That if evolution is occurring on an ongoing basis, we would discover new species?
How often do you think new species are discovered? When do you think is the last time a new species was discovered?

34. New Species Discovered
Cercopithecus Lomamiensis
Discovered in the Lomami forest in DR Congo
Discovered in 2012

35. New Species Discovered
Trogloraptor marchingtoni
Found in an Oregon Cave
Discovered in 2012