1. Principles, Populations, The history of life
Evolution
Principles,
Populations,
The history of life

3. Concept 10.1
Concept of Evolution
Process of biological change by which descendants come to differ from their ancestors
Search for reasons for Earth’s great biological diversity

4. Naturalist An expert in or student of natural history In Evolution
10.1
Naturalist
An expert in or student of natural history
In Evolution
Carolus Linnaeus
Georges Buffon
Erasmus Darwin
Jean-Baptiste Lamarck
These men laid the foundations in the early ideas of evolution

5. Scientists and their Contributions
10.1
Scientists and their Contributions
Carolus Linnaeus- proposed a new system of organizations for plants animals, minerals, based upon their similarities
Georges Buffon- discussed important ideas about relationships among organisms, sources of biological variation, and the possibility of evolution
Erasmus Darwin- considered how organisms could evolve through mechanisms such as competition
Jean-Baptiste Lamarck- presented evolution as occurring due to environmental changes over long periods of time

6. Theories of Geological Change
10.1
Catastrophism
Different fossils could be found in different rock layers
States that natural disasters have occurred shaping landforms and causing species to go extinct
Gradualism
States that changes in landforms resulted from slow changes over time
Gradual change of a species through evolutions
Still referenced today
Uniformitarianism
States that the geologic processes were uniform through time
Changes occur at a constant rate and are ongoing
Favored theory of geologic change

7. Darwin’s Observations
10.2
Darwin’s Observations
Variation
Difference in the physical traits among individuals
Interspecific-among species groups
Intraspecific-one species
Adaptation
Feature that allows the organism to better survive in its environment
Ability to adapt to the surroundings can lead to genetic change
Based on his observations, he believed that geologic processes add up over time in a uniform manner (uniformitarianism)

8. Darwin’s Evidence

9. Selection Artificial Selection (breeding) Heritability
10.3
Selection
Artificial Selection (breeding)
Humans make use of the genetic variation in plants and animals and choose the favorable genes
Heritability
The ability of a trait to be passed down through generations
Natural Selection
Nature chooses the traits to pass on
Traits are only selected if they give the organism advantages
Affects phenotypes (physical traits)

10. 10.3
Natural Selection
Four main principles in the theory of Natural Selection
Variation
-Heritable differences in populations
Overproduction
-An increase in offspring, increases competition for resources
Adaptation
-Beneficial traits allow some organisms to thrive
Descent with modification
-The beneficial traits will be passed on over time, producing a species that is suited for survival and reproduction

11. Evidence of Evolution 10.4 Fossils Geography Embryology Anatomy
Fossil record set a time frame
Geography
Study of distribution of similar populations
Embryology
Similarities between larvae of different species
Anatomy
Homologous structures
-similar in structure, different functions
Analogous structures
-similar in function, different structure
Vestigial structures
-remnants of structures found in ancestors

14. Evolution of Populations

15. 11.1
Genetic Variation
Genetic variation increases the chances for members of a population to survive
The greater the variation in phenotypes, the greater chances of survival in a changing environment
Variation is stored in a gene pool, which factors in allele frequency

16. Distributions of Traits
11.2
Distributions of Traits
Normal Distribution
-The frequency is highest near the middle value and decreases towards the extremities
-Phenotypes near the middle are most common creating a bell shaped curve

17. Selection changes distributions
11.2
Selection changes distributions
Microevolution-
observable change in allele frequency
Can change the distribution in 3 ways
Directional Selection
Occurs when extreme phenotypes are favored
Ex: drug resistant bacteria
Stabilizing Selection
The intermediate phenotype is favored
Ex: Gall size in goldenrods
Disruptive Selection
The extreme phenotypes are favored
Ex: feather color in birds

18. Directional Stabilizing Directional
Name
that distribution

19. Genetic Drift
11.3
Movement of alleles between populations leads to gene flow
This change in frequency occurs in two ways:
Bottleneck Effect
Genetic drift occurs after the population has been greatly reduced
Founder Effect
Genetic drift occurs after a small number of the population leave and colonize a new area

20. Genetic Drift

21. Hardy-Weinberg Equilibrium
11.4
Hardy-Weinberg Equilibrium
Found a way to predict population frequencies using five conditions
If these conditions are met, then the population is not evolving
Very large population
No emigration or immigration
No mutations
Random mating
No natural selection

22. Hardy-Weinberg Equation
11.4
Hardy-Weinberg Equation
While populations rarely meet the criteria, this formula can be used to compare data
p2 + 2pq + q2 = 1
p = the frequency of the dominant allele (TT)
q = the frequency of the recessive allele (tt)

23. Five factors of evolution
11.4
Five factors of evolution
The Hardy-Weinberg equilibrium is not common in nature
In nature, populations evolve in response to environmental factors such as:
Genetic drift
Gene flow
Mutation
Sexual selection
Natural selection

24. Evolution, Isolation, Speciation
11.5
If gene flow stops then isolation occurs
Isolation leads to speciation, which is a rise of two or more species from one existing species
Examples include:
Behavioral Isolation
-mating behaviors
Reproductive Isolation
-populations can no longer mate with each other
Geographic Isolation
-physical barriers divide a population
Temporal Isolation
- timing prevents reproduction

25. 11.6
Patterns in Evolution
The effects of natural selection add up over many generations
Mating throughout generations is NOT random
The evolutionary paths of two or more species can become connected through the process of coevolution
Extinction and speciation events also appear in patterns in the fossil record

26. The History of Life

27. The Fossil Record
12.1
Fossils are more diverse than the giant dinosaur skeletons seen in museums
Fossils can be produced in several ways
Permineralization
Natural casts
Trace fossils
Amber preserved fossils
Preserved remains

28. Aging Fossils 12.1 Relative vs Radiometric dating
Relative- estimates the time during which an organism lived by comparing rock samples
Radiometric- uses natural decay of isotopes
Isotopes are atoms that have the same number of protons but different number of neutrons
An isotopes half-life is not effected by environmental conditions such as temperature of pressure

29. Radiocarbon dating

30. Geologic Time Scale
Index fossils are another tool to determine the age of rock layers
These fossils give information of a specific time span over large geographic areas
The time scale represents Earth’s major changes and consists of three major units
Eras
Periods
Epochs

31. Geologic Scale 12.2 Paleozoic Mesozoic Cenozoic Ancient life
mya
Mesozoic
Middle life
mya
Cenozoic
Recent life
65 mya-present

32. 12.5
Paleozoic
Members of every major animal group evolved within only a few years
More than 90% of marine life and 70% of land species went extinct
Multicellular animals radiated
The first vertebrates evolved
Also known as the Cambrian explosion!

33. Mesozoic 12.5 Known as the age of reptiles
Oldest direct ancestor of mammals first appeared
Three periods:
Triassic
Jurassic
Cretaceous
- ended with a bang!!!

34. Cenozoic Includes present time Two periods: Tertiary- Quaternary-
placental animals and monotremes
Homo sapiens evolved (100,000 ya)
Quaternary-
Included ice ages, the last of which occurred 10,000 years ago

35. Primate Evolution 12.6 During the Cretaceous period primates evolved
Characteristics included:
Flexible hands and feet
Forward looking eyes
Enlarged brains
Opposable thumbs

37. 12.6
Family Differences
Culture and tools are key components in human evolution
Utilization of tools lead to levels of cultural adaptations and sophistication of humans
Human evolution would not have advanced as it did without an enlarging skull and brain size