1. EVOLUTION
SB5. Students will evaluate the role of natural selection in the development of the theory of evolution.
EQ: What is the role of natural selection in the development of the theory of evolution?

2. SB5a. Trace the history of the theory.
LEQ: What is the history of the theory of evolution?

3. the preserved remains of ancient organisms
WRITE A DEFINITION:
EVOLUTION:
change over time; the process by which modern organisms have descended from ancient organisms
THEORY:
a well-supported testable explanation of phenomena that have occurred in the natural world
FOSSIL:
the preserved remains of ancient organisms

4. Where did all these different organisms come from?
REMEMBER !
The total variety of all the organisms in the biosphere
= ________________
Where did all these different organisms come from?
How are they related?
BIODIVERSITY

5. History of the Theory of Evolution
There were theories of biological and geologic change before Darwin.
Early scientists proposed ideas about evolution (Aristotle).
Evolution is the process by which species of organisms change over time
A species is a group of organisms that can reproduce and have fertile offspring.

6. History of the Theory of Evolution
There were many important naturalists in the 18th century.
Linnaeus: classification system from kingdom to species.
Gregor Mendel: Heredity
Lamarck: organisms change due to demands of environment
Principle of use or disuse
Inheritance of acquired characteristics……turned out to be false
Malthus: Essay on the Principle of Populations
Populations will naturally outgrow their food resources leading to competition.

7. Theories of geologic change set the stage for Darwin’s theory.
History of the Theory of Evolution
Theories of geologic change set the stage for Darwin’s theory.
There were three theories of geologic change.
catastrophism
BONNET
gradualism
HUTTON
uniformitarianism
LYELL

8. Darwin observed differences among island species.
History of the Theory of Evolution
Darwin’s voyage provided insight on evolution.
Darwin observed differences among island species.
Variation is a difference in a physical trait.
Galapagos tortoises neck length and shell shape.
Galápagos tortoises that live in areas with tall plants have long necks and legs.
Galápagos tortoises that live in areas with short plants have small necks and legs.
Darwin published his findings/ideas in the book On the Origin of Species

9. History of the Theory of Evolution
Darwin’s Finches
Different Island =
Different Beak shape

10. History of the Theory of Evolution
He saw land move from underwater to above sea level due to an earthquake.
Darwin extended his observations to the evolution of organisms.
If the earth has had such drastic geological changes, organisms must have had to change with it in order to survive.

11. History of the Theory of Evolution
Darwin observed fossil and geologic evidence supporting an ancient Earth.
Darwin found fossils of extinct animals that resemble modern animals.
Darwin found fossil shells high up in the Andes mountains which supported his claim of major geological changes.

12. Darwin’s Conclusions Two main concepts….basis of his theory
Natural selection:
idea that organisms with favorable variations for their environment survive, reproduce, and pass those variations to the next generation.
Reproductive Isolation:
physical separation of organisms due to geographic barriers lead to the inability of organisms to interbreed.
Allows different populations of a species to adapt to different environments.
This leads to speciation.

13. Alfred Wallace
At the same time as Darwin, Wallace was formulating his own theory.
Evolution results from competition for resources within a population.
Concept that built upon the concepts of Malthus.
Darwin and Wallace agreed that natural selection was part of evolution…..However, Wallace thought that competition NOT reproductive success was the driving force.

14. SB5b. Explain the history of life in terms of biodiversity, ancestry, and the rates of evolution. c. Explain how fossil and biochemical evidence support the theory of evolution.
LEQ: What is the history of life and what evidence do we have to support the theory of evolution?

15. History of Life
The geologic time scale divides Earth’s history based on major past events. The geologic time scale organizes the earth’s history
100
250
550
1000
2000
PRECAMBRIAN TIME
Cyanobacteria
This time span makes up the vast majority of Earth’s history. It includes the oldest known rocks and fossils, the origin of eukaryotes, and the oldest animal fossils.
The history of Earth is represented in the geologic time scale.
The earth is thought to be approximately 4.6 billion years old.

16. History of Life Eras last tens to hundreds of millions of years.
Consist of two or more periods
Three eras: Cenozoic, Mesozoic, Paleozoic

17. Epochs last several million years.
History of Life
Periods last tens of millions of years.
most commonly used units of time on time scale
associated with rock systems.
Epochs last several million years.

18. History of Life
Huge continent made up of all the land masses on earth.
Reptiles appeared and dominated
Birds and mammals appeared
Plants evolved adaptations (flowers)
Mass Extinctions occurred
PANGEA

19. History of Life
PANGEA
Although extinctions usually happened at a fairly constant rate, sometimes huge numbers disappeared in periodic mass extinctions.
If the history of earth was squeezed into a single day, the human species would not have appeared until the last few seconds.

20. Earth was very different billions of years ago.
History of Life
The origin of life on Earth remains a puzzle.
There have been many hypotheses of Earth’s origins.
The most widely accepted hypothesis of Earth’s origins is the nebula hypothesis.
Earth was very different billions of years ago.

21. Single-celled organisms existed 3.8 billion years ago.
History of Life
Several sets of hypotheses propose how life began on Earth and early cell structures.
Although the origins of live are not completely known the presence of life on earth has existed for 3.8 billion years.
Single-celled organisms existed 3.8 billion years ago.

22. History of Life
A hypothesis proposes that RNA was the first genetic material.

23. Microbes have changed the physical and chemical composition of Earth.
History of Life
Microbes have changed the physical and chemical composition of Earth.
The oldest known fossils are a group of marine cyanobacteria.
prokaryotic cells
added oxygen to atmosphere
deposited minerals

24. Fossil provide evidence of early colonies of life.
History of Life
Fossil provide evidence of early colonies of life.

25. Eukaryotic cells may have evolved through endosymbiosis.
History of Life
Eukaryotic cells may have evolved through endosymbiosis.
Endosymbiosis is a relationship in which one organism lives within the body of another.
Mitochondria and chloroplasts may have developed through endosymbiosis.

26. The evolution of sexual reproduction led to increased diversity.
History of Life
The evolution of sexual reproduction led to increased diversity.
Genetic variation is an advantage of sexual reproduction.
Sexual reproduction may have led to the evolution of multicellular life.
Multicellular life evolved in distinct phases.

27. Life moved onto land during the Paleozoic Era.
History of Life
Life moved onto land during the Paleozoic Era.
Multicellular organisms first appeared during the Paleozoic era.
The era began 544 million years ago and ended 248 million years ago.
The Cambrian explosion led to a huge diversity of animal species.

28. Reptiles radiated during the Mesozoic era.
History of Life
Reptiles radiated during the Mesozoic era.
The Mesozoic era is known as the Age of Reptiles.
It began 248 million years ago and ended 65 million years ago.
Dinosaurs, birds, flowering plants, and first mammals appeared.

29. Mammals radiated during the Cenozoic era.
History of Life
Mammals radiated during the Cenozoic era.
The Cenozoic era began 65 million years ago and continues today.
Placental mammals and monotremes evolved and diversified.
Anatomically modern humans appeared late in the era. Humans appeared late in Earth’s history.

30. Humans share a common ancestor with other primates.
History of Life
Humans share a common ancestor with other primates.
Primates are mammals with flexible hands and feet, forward-looking eyes and enlarged brains.

31. History of Life Anthropoids are humanlike primates.
They are subdivided into the New World monkeys, Old World monkeys, and hominoids.
Homonoids are divided into hominids, great apes, and lesser apes.
Hominids include living and extinct humans.

32. History of Life Bipedal means walking on two legs.
foraging
carrying infants and food
using tools
Walking upright has important adaptive advantages.

33. There are many fossils of extinct hominids.
History of Life
There are many fossils of extinct hominids.
Most hominids are either the genus Australopithecus or Homo.
Australopithecines were a successful genus.
The Homo genus first evolved 2.4 million years ago.

34. Modern humans arose about 200,000 years ago.
History of Life
Modern humans arose about 200,000 years ago.
Homo sapiens fossils date to 200,000 years ago.
Human evolution is influenced by a tool-based culture.
There is a trend toward increased brain size in hominids.
Australopithecus
afarensis
Homo habilis
Homo
neanderthalensis
Homo sapiens

35. Evidence for Evolution
Evidence of common ancestry among species comes from many sources.
Fossil
Geography
Embryology
Anatomy
Molecular and Genetic

36. Evidence for Evolution
Fossils provide evidence of evolution.
Fossils in older layers are more primitive than those in the upper layers.
Paleontology is the study of fossils or extinct organisms.

37. Evidence for Evolution
Radiometric dating provides an accurate way to estimate the age of fossils.
Relative dating estimates the time during which an organism lived.
It compares the placement of fossils in layers of rock.
Scientists infer the order in which species existed.

38. Evidence for Evolution
Radiometric dating uses decay of unstable isotopes.
Isotopes are atoms of an element that differ in their number of neutrons.
A half-life is the amount of time it takes for half of the isotope to decay.
Carbon-14 is used to find the age of organic material found in fossils.
Why do we use carbon?

39. Preserved remains form when an entire organism becomes encased in material such as ice.

40. Evidence for Evolution
The study of geography provides evidence of evolution.
island species most closely resemble nearest mainland species
populations can show variation from one island to another

41. Evidence for Evolution
Embryology provides evidence of evolution.
identical larvae, different adult body forms
similar embryos, diverse organisms
Larva
Adult barnacle
Adult crab

42. Evidence for Evolution
The study of anatomy provides evidence of evolution.
Homologous structures are similar in structure but different in function.
provide evidence of a common ancestor.
Human hand
Bat wing
Mole foot

43. Evidence for Evolution
The study of anatomy provides evidence of evolution.
Analogous structures have a similar function.
Not evidence of a common ancestor.
Bat wing
Mole foot
Fly wing

44. Evidence for Evolution
Structural patterns provide evidence of evolution
Vestigial structures are remnants of organs or structures that had a function in an early ancestor but are no longer functioning/needed in present organism.
Example:
ostrich wings
molars in vampire bats

45. Evidence for Evolution
New technology is furthering our understanding of evolution.

46. Evidence for Evolution
Molecular and genetic evidence support fossil and anatomical evidence.
Two closely-related organisms will have similar DNA sequences.

47. SB5d. Relate natural selection to changes in organisms.
LEQ2. How does natural selection relate to changes in organisms?

48. Heritability is the ability of a trait to be passed down
Natural Selection
Natural selection is a mechanism by which individuals that have inherited beneficial adaptations produce more offspring on average than do other individuals.
Heritability is the ability of a trait to be passed down
Natural Selection selects for the fittest organisms in an environment.
Fitness is the measure of survival ability and ability to produce more offspring.

49. Natural selection explains how evolution can occur.
There are four main principles to the theory of natural selection
Variation
Overproduction
Adaptation
Descent with Modification
Natural selection explains how evolution can occur.

50. Natural Selection
Variation is the differences in traits within a population
Variation is inherited.
Variation exists between all organisms.
Some variations are beneficial to an organism some are not.
VARIATION
Variation within a population may be caused by mutations and genetic recombination

51. Genetic variation comes from several sources.
Natural Selection
Genetic variation comes from several sources.
Mutation is a random change in the DNA of a gene.
can form new alleles
can be passed on to offspring if in reproductive cells
Recombination forms new combinations of alleles.
usually occurs during meiosis
parents’ alleles arranged in new ways in gametes

52. Natural Selection
Genetic variation in a population may increase the fitness of an organisms or the chance that some individuals will survive.
Genetic variation can lead to phenotypic variation.
Phenotypic variation is necessary for natural selection.
Genetic variation is stored in a population’s gene pool.
made up of all alleles in a population
allele combinations form when organisms have offspring

53. Factors that lead to death of organisms:
Natural Selection
Overproduction
Struggle for Existence
Species compete to stay alive in terms of food, homes, reproduction
Survival of the Fittest
When members of a species develop adaptations naturally that increase their fitness—or ability to survive an reproduce—in its environment
The strongest organisms survive and pass their advantageous traits onto the next generation.
Factors that lead to death of organisms:
Predator
Disease
Other factors
There is a struggle for survival due to overpopulation and limited resources.

54. Darwin proposed that adaptations arose over many generations.
Natural Selection
An adaptation is a feature that allow an organism to better survive in its environment.
Species are able to adapt to their environment.
Adaptations can lead to genetic change in a population.
Darwin proposed that adaptations arose over many generations.
ADAPTATION

55. Descent with Modification
Natural Selection
Descent with Modification
Species alive today have descended with modifications from species that lived in the past.
Evolution is then change between generations within a population.
All organisms on Earth are united into a single tree of life by common descent.

56. Natural selection acts on existing variation.
Natural selection can act only on traits that already exist.
wrist bone
five digits
Natural Selection is the process that explains how evolution can occur.

57. There are six factors that can lead to evolution.
Natural Selection
There are six factors that can lead to evolution.
Genetic drift
Gene Flow
Mutations
Sexual Selection
Natural Selection
Reproductive Isolation
Populations, not individuals, evolve.

58. Natural Selection
Genetic drift changes allele frequencies due to chance alone.

59. Natural Selection
Gene flow moves alleles from one population to another.

60. Natural Selection
Mutations produce the genetic variation needed for evolution.

61. Natural Selection
Sexual selection selects for traits that improve mating success.

62. Natural Selection
Natural selection selects for traits advantageous for survival.

63. Natural Selection
Reproductive isolation can occur between isolated populations.
members of different populations cannot mate successfully
final step to becoming separate species which is speciation.
Speciation is the rise of two or more species from one existing species.

64. The isolation of populations can lead to speciation.
Natural Selection
The isolation of populations can lead to speciation.
Populations become isolated when there is no gene flow.
Isolated populations adapt to their own environments.
Genetic differences can add up over generations.
Causes of isolation:
Behavioral barriers
includes differences in courtship or mating behaviors
Temporal barriers
timing of reproductive periods prevents mating
Geographic barriers
physical barriers divide population

65. Evolution through natural selection is not random.
Natural selection can have direction.
The effects of natural selection add up over time.

66. Natural Selection can change the distribution of a trait.
Directional selection
Occurs when one extreme phenotype is favored
Disruptive selection
Occurs when both extreme phenotypes are favored
Stabilizing Selection
Occurs when the intermediate phenotype is favored.

67. Evolution occurs in patterns
Natural Selection
Evolution occurs in patterns
Types of evolutionary patterns:
Convergent evolution
Divergent evolution
Coevolution

68. Natural Selection Types of evolution
Divergent evolution describes evolution toward different traits in closely related species.
Convergent evolution describes evolution toward similar traits in unrelated species.
How do convergent and divergent evolution illustrate the directional nature of natural selection?
ancestor
red fox
kit fox

69. Species can shape each other over time.
Natural Selection
Species can shape each other over time.
Two or more species can evolve together through coevolution.
evolutionary paths become connected
species evolve in response to changes in each other
Can occur in all types of relationships: beneficial and competitive

70. Species can become extinct.
Natural Selection
Species can become extinct.
Extinction is the elimination of a species from Earth.
Background extinctions occur continuously at a very low rate.
occur at roughly the same rate as speciation
usually affects a few species in a small area
caused by local changes in environment

71. Speciation often occurs in patterns.
Natural Selection
Speciation often occurs in patterns.
A pattern of punctuated equilibrium exists in the fossil record.
theory proposed by Eldredge and Gould in 1972
episodes of speciation occur suddenly in geologic time
followed by long periods of little evolutionary change
revised Darwin’s idea that species arose through gradual transformations

72. Natural Selection
Many species evolve from one species during adaptive radiation.
ancestral species diversifies into many descendent species
descendent species usually adapted to wide range of environments

73. e. Recognize the role of evolution to biological resistance
LEQ5. What is the role of evolution in biological resistance?

74. What is a “ super bug?”
Bacterial strand that is resistant to treatment from antibiotics
Evolved from:
Unnecessary use of prescription antibiotics
Overdose of antibiotics

75. What are Antibiotics?
Compound that kills or limits the growth and reproduction of bacteria
They cannot be used to treat viral infections only bacterial.
Penicillin- discovered by Alexander Fleming in 1928.
Substance secreted by a certain fungus
Lead to the creation of numerous antibiotics used to treat several different bacterial diseases
Pneumonia, tuberculosis

76. Applications of Antibiotics
Used to treat human illness
Prevent infection in healthy livestock
Found in commercial feed that is given to chickens and other farm animals
Over $20 Billion is spent worldwide on antibiotics each year

77. Natural Selection
Increase in antibiotic use leads to decrease in effectiveness
Some bacteria have the genetic ability to survive in the presence of an antibiotic
These bacteria survive and reproduce
Passing this trait to their offspring
Result:
Population of disease causing bacteria that are resistant to antibiotics
More we use antibiotics, increase number of resistant strands

78. Limit effects of biological resistance
Limit the non-medical and unnecessary use of antibiotics
Take antibiotics as they are prescribed and for the full duration.
Stop taking prematurely resistant bacteria thrive and reproduce
Creation of new antibiotics
Use of combination drugs

79. Other Biological Resistance
Insects and other pests have become resistant to certain pesticides
Some widely used pesticides have become ineffective
Population of insects is not longer affected by the pesticide
Example: DDT