1. Evolution

2. Journal
What is evolution?

3. Journal
What is necessary for a species to survive?

4. Evolution
A collection of facts, observations, and hypotheses about the history of life
A change over a period of time; change in the gene pool of a population over time

5. Gene
A hereditary unit that can be passed on unaltered for many generations

6. Gene Pool
The set of all genes in a species or population

7. Evolution Example
Peppered Moths
Dark Moths 2% in 1848

11. By 1898 95% of the moth population was made up of the dark morph moth

12. The moth population changed from light colored moths to mostly dark in about 50 years. The change in the frequency of the dark colored moths was determined by a single gene.

13. Do individual organisms evolve?
NO!

14. Individual organisms do not evolve; they retain the same genes throughout their life.
Populations evolve.

15. Genes Mutate. Individuals are selected. Populations evolve.

16. Evolution is not progress.
Populations adapt to their surroundings.
Organisms are not passive targets of their environments. Each species modifies its own environment.

17. Charles Darwin & Natural Selection

18. What was Charles Darwin’s contribution to science?
Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

19. Charles Darwin Naturalist who traveled aboard the H.M.S. Beagle
On his voyage his powerful observation helped him to notice things others had missed
Darwin developed a scientific theory of biological evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors.

20. Charles Darwin was born in England on February 12, 1809
Charles Darwin was born in England on February 12, He grew up at a time when the scientific view of the natural world was shifting dramatically.
Geologists were suggesting that Earth was ancient and had changed over time, and biologists were suggesting that life on Earth had also changed.
The process of change over time is called evolution.

21. Darwin’s Epic Journey
Darwin was invited to sail on the HMS Beagle’s five-year voyage mapping the coastline of South America.
Darwin planned to collect specimens of plants and animals on the voyage.
No one knew it, but this would be one of the most important scientific voyages in history.

22. Darwin’s 3 patterns of Biological Diversity
1. Species vary globally
2. Species vary locally.
3.Species vary over time.

23. Observations Aboard the Beagle
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe.
Darwin noticed that different, yet related, animal species often occupied different habitats within a local area.
Darwin noticed that some fossils of extinct animals were similar to living species.

24. Darwin filled his notebooks with observations about the characteristics and habitats of the different species he saw.
Darwin wanted to explain the biological diversity he observed in a scientific way. He looked for larger patterns into which his observations might fit.

25. Studied specimens, read scientific books, and thought about what he had seen
Collected plant & animal specimens wherever he went
Observed living diversity & fossil diversity

26. Species Vary Globally
Darwin noticed that different, yet ecologically similar, animal species inhabited separated, but ecologically similar, habitats around the globe.
For example, Darwin found flightless, ground- dwelling birds called rheas living in the grasslands of South America. Rheas look and act a lot like ostriches. Yet rheas live only in South America, and ostriches live only in Africa. When Darwin visited Australia’s grasslands, he found another large flightless bird, the emu.

27. Darwin also noticed that rabbits and other species living in European grasslands were missing from the grasslands of South America and Australia.
Australia’s grasslands were home to kangaroos and other animals that were found nowhere else.
What did these patterns of geographic distribution mean?

28. Species Vary Locally
Darwin noticed that different, yet related, animal species often occupied different habitats within a local area.
For example, Darwin found two species of rheas living in South America: one in Argentina’s grasslands and the other in the colder, harsher grass and scrubland to the south.

29. Other examples of local variation came from the Galápagos Islands, about 1000 km off the Pacific coast of South America.
These islands are close to one another, yet they have different ecological conditions. Several islands were home to distinct forms of giant land tortoises.
Darwin saw differences among the giant land tortoises that inhabit the islands and learned from the islands’ governor that the tortoises’ shells varied in predictable ways from one island to another.

30. The shape of the tortoises’ shells corresponds to different habitats.
Isabela Island has high peaks, is rainy, and has abundant vegetation that is close to the ground.
A tortoise from Isabela Island has a dome-shaped shell and short neck.
Hood Island, in contrast, is flat, dry, and has sparse vegetation.
A long neck and a shell that is curved and open around the neck and legs allow the Hood Island tortoise to reach sparse, high vegetation.

31. Darwin also observed that different islands had different varieties of mockingbirds, all of which resembled mockingbirds Darwin had seen in South America.
In addition, Darwin noticed several types of small brown birds on the islands with beaks of different shapes. He didn’t consider these smaller birds to be unusual or important—at first.

32. Species vary over time
Darwin also collected fossils, which are the preserved remains or traces of ancient organisms.
Darwin noticed that some fossils of extinct animals were similar to living species.

33. One set of fossils unearthed by Darwin belonged to the long-extinct glyptodont, a giant armored animal similar to the armadillo. Darwin wondered if the armadillo might be related to the ancient glyptodont.
Why had glyptodonts disappeared? And why did they resemble armadillos?

34. Putting the Pieces of the Puzzle Together
On the voyage home, Darwin thought about the patterns he’d seen. Darwin sent plant and animal specimens to experts for identification.
The Galápagos mockingbirds turned out to belong to three separate species found nowhere else.
The little brown birds were actually all species of finches, also found nowhere else, though they resembled a South American finch species.
The same was true of Galápagos tortoises, marine iguanas, and many plants that Darwin had collected on the islands.

35. Darwin began to wonder whether different Galápagos species might have evolved from South American ancestors.
He spent years actively researching and filling notebooks with ideas about species and evolution.
The evidence suggested that species are not fixed and that they could change by some natural process.

36. Catastrophists
earth had experienced a succession of creations of plant & animal life and each creation had been destroyed by a sudden catastrophe
Species were individually created and unchangeable

37. Sir Charles Lyell Challenged the catastrophists viewpoint
Principles of Geology
Maintained that the earth’s surface is undergoing constant change, the result of natural forces operating uniformly over long periods

38. Darwin found himself fitting many of his observations into Lyell’s general uniformitarian view

39. Living Diversity
Darwin was amazed by the tremendous variety of animals & plants that inhabited the earth
Ex. In just one days work in a Brazilian Rain Forest he observed more than 68 different species of beetles

40. Living Diversity—the variety of living things; the diversity of life

41. Fossil Diversity
The variety of the fossilized remains of creatures that lived long ago

42. Estimated that 99.9% of all species that have ever inhabited the earth are now extinct

43. Darwin & The Galapagos Islands

44. Galapagos Islands
Chain of islands located in the Pacific Ocean west of South America

46. Provided Darwin with his greatest inspiration
Darwin was fascinated by the wildlife especially the land tortoises & marine iguanas
Birds showed a variety of different Beak Shapes

49. animals.nationalgeographic.com/animals/printa...

53. Wondered whether animals living on different islands had once been members of the same species & had changed after they were isolated from one another

54. Darwin noticed that every species seemed remarkably well suited to the life it leads

55. Thomas Malthus An Essay on the Principle of Population (1798)
British economist

56. Explained how populations remain in balance
Argued that any increase in the availability of food for basic human survival could not match the geometrical rate of population growth

57. Observed that babies were being born faster than people were dying
Suggested that war, famine & disease would limit the population

58. On The Origin of Species
Darwin’s book in which his complete theory of evolution through natural selection was published (1859)

59. Because of the food supply problem the young born to any species intensely compete for survival
The young that survive to produce the next generation tend to embody favorable natural variations which are passed on by heredity

60. 1. Assembled large amounts of evidence supporting the idea that life has changed or evolved over time
2. proposed a scientific hypothesis to explain how and why evolution occurs

61. Some Evidnece

62. Biogeography
Biogeography is the study of where organisms live now and where they and their ancestors lived in the past.
Two biogeographical patterns are significant to Darwin’s theory.
The first is a pattern in which closely related species differentiate in slightly different climates.
The second is a pattern in which very distantly related species develop similarities in similar environments.

63. Closely Related but Different
To Darwin, the biogeography of Galápagos species suggested that populations on the island had evolved from mainland species.
Over time, natural selection on the islands produced variations among populations that resulted in different, but closely related, island species.
For example, natural selection produced variation in shell shape among the giant land tortoises that inhabit the islands.

64. Distantly Related but Similar
On the other hand, similar habitats around the world are often home to animals and plants that are only distantly related.
Darwin noted that similar ground-dwelling birds (rheas, ostriches, and emus) inhabit similar grasslands in Europe, Australia, and Africa.
Differences in body structures among those animals provide evidence that they evolved from different ancestors.
Similarities among those animals, however, provide evidence that similar selection pressures had caused distantly-related species to develop similar adaptations.

65. Recent Fossil Finds
Darwin’s study of fossils had convinced him and other scientists that life evolved, but paleontologists in 1859 hadn’t found enough fossils of intermediate forms of life to document the evolution of modern species from their ancestors.
Since Darwin, paleontologists have discovered hundreds of fossils that document intermediate stages in the evolution of many different groups of modern species.

66. Recent Fossil Finds

67. Recent Fossil Finds
The limb structure of Ambulocetus (“walking whale”) suggests that these animals could both swim in shallow water and walk on land.

68. Comparing Anatomy and Embryology
What do homologous structures and similarities in embryonic development suggest about the process of evolutionary change?
Evolutionary theory explains the existence of homologous structures adapted to different purposes as the result of descent with modification from a common ancestor.

69. Comparing Anatomy and Embryology
By Darwin’s time, scientists had noted that all vertebrate limbs had the same basic bone structure.
For example, the front limbs of amphibians, reptiles, birds, and mammals contain the same basic bones.

70. Homologous Structures
Darwin proposed that animals with similar structures evolved from a common ancestor with a basic version of that structure.
Structures that are shared by related species and that have been inherited from a common ancestor are called homologous structures.
Biologists test whether structures are homologous by studying anatomical details, the way structures develop in embryos, and the pattern in which they appeared over evolutionary history.

71. Homologous Structures
Homologous bones, as shown by color-coding, support the differently-shaped front limbs of modern vertebrates.

72. Homologous Structures
These limbs evolved, with modifications, from the front limbs of a common ancestor whose bones resembled those of an ancient fish.
Similarities and differences among homologous structures help determine how recently species shared a common ancestor.
For example, the front limbs of reptiles and birds are more similar to each other than either is to the front limb of an amphibian or mammal. This similarity—among many others— indicates that the common ancestor of reptiles and birds lived more recently than the common ancestor of reptiles, birds, and mammals.

73. Homologous Structures
Biologists have identified homologies in many other organisms.
Certain groups of plants, for example, share homologous stems, roots, and flowers.

74. Homologous Structures
Develop from similar tissues in the early developmental stages of an organism even though they appear to be different on the outside
Ex. Arm of a human and front leg of a horse

77. Adaptations
Physical & behavioral traits that enable organisms to survive
Found at every level of biology

79. What is necessary for a species to survive?

80. For a species to survive it must do more than just stay alive—it must reproduce

81. Fitness The ability of an individual to survive and reproduce
Today—based on an organism’s ability to successfully pass on its genes to its offspring

82. Natural Selection
Process in nature that over time results in the survival of the fittest

83. Explains how over time species become better suited to their environment as they respond to various selection pressures

84. Sorts out useful changes in the gene pool
Beneficial new genes spread quickly through a population
Genes that are not as good for an organism are eliminated

85. Only allows organisms to adapt to their current environment
When the environment changes new traits may appear

86. Natural selection does not always favor change; some organisms may change for the worse

87. Natural Selection
This hypothetical population of grasshoppers changes over time as a result of natural selection.
Grasshoppers can lay more than 200 eggs at a time, but only a small fraction of these offspring survive to reproduce.

88. Natural Selection
Certain variations, called adaptations, increase an individual’s chances of surviving and reproducing.
In this population of grasshoppers, heritable variation includes yellow and green body color.
Green color is an adaptation: The green grasshoppers blend into their environment and so are less visible to predators.

89. Natural Selection
Because their color serves as a camouflage adaptation, green grasshoppers have higher fitness and so survive and reproduce more often than yellow grasshoppers do.

90. Natural Selection
Green grasshoppers become more common than yellow grasshoppers in this population over time because more grasshoppers are born than can survive, individuals vary in color and color is a heritable trait, and green grasshoppers have higher fitness in this particular environment

91. Common Descent
New organisms did not spontaneously appear, but occurred from a common origin over a long. Slow evolutionary change

92. Common ancestors
each living species has descended from other species over time

93. Evolution provides a unifying principle that underlies all of biology.
Evolution is driven by the environment

94. Provided support for the older concept that the earth itself is not static but evolving