1. Unit 10: History of Biological Diver PAP Evolution: Darwin’s travel

2. Developing the Theory of Evolution The Galápagos Islands
Darwin noticed that the different islands all seemed to have their own, slightly different varieties of animals.
Somewhat similar species that suited their particular environment.
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Darwin’s Theory of Evolution by Natural Selection

3. Origin of Species: Darwin’s Book
In 1859 On the Origin of Species presented evidence and proposed a mechanism for evolution that he called natural selection.

5. Today, scientists use evolution to mean cumulative change in a group of organisms through time.
Natural selection is not synonymous with evolution – it is a mechanism by which evolution occurs.
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Darwin’s Theory of Evolution by Natural Selection

6. Peppered Moth: Natural Selection
The light colored form was the predominant form in England prior to the Industrial Revolution.
Around the middle of the 19th century the darker form began to appear. It was first reported in By % of the moths in Manchester were the dark variety.
In recent years, the burning of cleaner fuels and Clean Air regulations has reduced the pollution there and the lighter colored moths have increased in numbers.

7. Natural Selection:
a. Artificial Selection – humans select for variations
in plants and animals that they find useful.
b. Natural Selection
– also means “Survival of the Fittest”.
- Fitness in this sense does not mean strongest.
- Fitness in Darwin terms means reproduction. The one who survives long enough to reproduce the most is the one with the highest fitness.

8. Types of Selection
-Evolution acts on the phenotype of the individual, not the genotype.
- There are 4 types of selection that can occur on a population.
1. Directional Selection
– when individuals at one end of the curve have a higher fitness than individuals in the middle or at the other end of the curve.

9. 2. Stabilizing Selection
– when individuals near the center of the curve have higher fitness than individuals at either end of the curve, narrowing of the graph.

10. a. genetic drift – random change in allele frequency.
3. Disruptive Selection
– when individuals at either end have a higher fitness and individual near the middle of the curve are selected against.
- Over time with enough selection a population can go through genetic drift.
a. genetic drift – random change in allele frequency.

11. 4. Sexual Selection: the ability to attract a mate

12. Worksheet

13. Support for Evolution Evidence for evolution comes from:
1. The fossil record: remains in layers of rock
2. Comparative anatomy
a. Analogous structures
b. Homologous Structures
c. Vestigial Structures
3. Comparative embryology:
4. Comparative biochemistry
5. Geographic distribution
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Evidence of Evolution

14. 1. Support of Evolution: Fossil Record
Fossil Record – Fossils are the remains of ancient organisms found in layers of rock in the Earth.

15. Support of Evolution
The layers of rock tell the history of the Earth, while the fossils found within the rock tell a history of life.
The fossils are thought to be the same age as the rock they are found in.

16. Support for Evolution: The fossil Record
Researchers consider two major classes of traits when studying transitional fossils:
Derived traits are newly evolved features, such as feathers, that do not appear in the fossils of common ancestors.
Ancestral traits are more primitive features, such as teeth and tails, that do appear in ancestral forms.
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Evidence of Evolution

17. 2. Support for Evolution: Comparative Anatomy
A. Homologous structures are anatomically similar structures inherited from a common ancestor.
Similar structures with different function (similar bones) (common ancestor)
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Evidence of Evolution

18. Structures are different but have similar function
Support for Evolution
Comparative anatomy
B. Analogous structures can be used for the same purpose and be superficially similar in construction, but are not inherited from a common ancestor.
Structures are different but have similar function
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Evidence of Evolution

19. Support for Evolution
Comparative anatomy
C. Vestigial structures are structures that are the reduced forms of functional structures in other organisms.
Evolutionary theory predicts that features of ancestors that no longer have a function for that species will become smaller over time until they are lost.
snake pelvis
human appendix
Evidence of Evolution
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20. 3. Support for Evolution: Comparative embryology
Embryos of many animals with back-bones are very similar.

21. Similarities in DNA and protein sequences suggest relatedness.
4. Support for Evolution: Comparative Biochemistry
Common ancestry can be seen in the complex metabolic molecules that many different organisms share.
The more closely related species are to each other, the greater the biochemical similarity.
Similarities in DNA and protein sequences suggest relatedness.
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Evidence of Evolution

22. 5. Support for Evolution: Geographic distribution
The distribution of plants and animals that Darwin were what first suggested evolution to him.
The distribution of plants and animals around the world is studied in the field of biogeography.
Evolution is linked to migration patterns, climate, and geological forces (such as plate tectonics).
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Evidence of Evolution

23. Activity

24. Adaptation- an inherited trait that increases a population’s chance of survival and reproduction in a particular environment
Fitness is a measure of the relative contribution an individual trait makes to the next generation.
The better an organism is adapted to its environment, the greater its chances of survival and reproductive success.
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Evidence of Evolution

25. Through adaptations, populations often
become suited to a specific job called a niche.
1. niche – the role a population plays in a habitat
- job, profession, role
2. Competition arises when 2 populations
occupy the same niche.

26. Adaptation Types of adaptations
Camouflage
Adaptation
Types of adaptations
Camouflage is a suite of morphological adaptations that allow an organism to blend into its environment.
Mimicry is a type of morphological adaptation where a species evolves to resemble another species.
Antimicrobial resistance develops in some bacteria in response to sub-lethal exposure to antibiotics.
Mimicry
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Evidence of Evolution

28. Population Genetics - study of the traits in a population
A. Population – a group of interbreeding organisms (a species) living in a given area
B. Gene Pool – combined genetic material of all the members of a population
C. Gene Flow-the transfer of allele or genes from one population to another
D. Genetic Drift- any change in the allelic frequency in a population that results from chance

29. E. Allele – forms that a gene can take
F. Allele Frequency – the number of each allele for a trait
2. This “changing of the gene pool” (allele frequency) has a name —› Evolution.
3. Evolution – the changes in the gene pool of a population over time.

30. Speciation – formation of a new species Reproductive Isolation
- 2 or more species can not interbreed
Prezygotic: Its happens before fertilization: different reproductive times and different mating songs.
Postzygotic: Its happens after fertilization: fertilization has occurred but results in sterile offspring (Mule)
Horse 60 chromosomes gametes 30
Donkey 62 Chromsomes gametes 31
Example: Three similar species of orchid all live in the same rain forest. Each species releases pollen only on a single day. Because they release the pollen on different days, they cannot pollinate one another.

31. 1. Behavioral Isolation
- occurs when 2 populations are capable of interbreeding but have differences in courting rituals or breed at different times
Example: The eastern and the western meadowlark have overlapping ranges, but they do not interbreed because they have different mating songs.

32. 2. Geographic /Allopatric Isolation
- 2 populations are separated by geographic barriers
●examples: rivers, mountains, bodies of water
Example: These squirrels are geographically separated by the grand canyon.

33. Types of Evolution Convergent Evolution: less alike to more alike
Divergent Evolution=Adaptive Radiation: more alike to less alike
Coevolution: evolve together
Punctuated equilibrium: happens in short period of time

34. Convergent Evolution:
Occurs when different organisms that live in similar environments become more alike in appearance and behavior.
Less alike to more alike
Examples: - Bird wings/insect wings
- Shark fins/dolphin fins
Draw the diagram in Notes

35. Divergent Evolution=Adaptive Radiation
One species give rise to many species
More alike to less alike
Also known as adaptive radiation.
Examples: - Darwin’s Finches.
- Brown bears and polar bears
Draw this diagram in notes

36. Punctuated equilibrium
Gradual equilibrium
predicts that a lot of evolutionary change takes place in short periods of time tied to speciation events.
Predicts that little of evolutionary change takes place in small gradual steps