KEY CONCEPT There were theories of biological and geologic change before Darwin.

1. KEY CONCEPT There were theories of biological and geologic change before Darwin.

2. Early scientists proposed ideas about evolution. • Evolution is the biological change process by which descendants come to differ from their ancestors. • A species is a group of organisms that can reproduce and have fertile offspring.

3. Linnaeus: classification system from kingdom to species • Buffon: species shared ancestors rather than arising separately • E. Darwin: more-complex forms developed from less-complex forms • Lamarck: environmental change leads to use or disuse of a structure • There were many important naturalists in the 18th century.

4. Theories of geologic change set the stage for Darwin’s theory. • There were three theories of geologic change. • catastrophism • gradualism • uniformitarianism

5. Uniformitarianism is the prevailing theory of geologic change.

6. What term describes the theory that natural disasters shaped Earth's landforms and caused species to become extinct? • Which scientist developed a classification system based on similarities? • Which theory of geologic change is accepted by today's scientists? Human effects on evo Posters

7. KEY CONCEPT Darwin’s voyage provided insight on evolution.

8. Darwin observed differences among island species. • Variation is a difference in a physical trait. • Galápagos tortoises that live in areas with tall plants have long necks and legs. • Galápagos finches that live in areas with hard-shelled nuts have strong beaks.

9. Species are able to adapt to their environment. • Adaptations can lead to genetic change in a population. • An adaptations is a feature that allow an organism to better survive in its environment.

10. 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.

11. He saw land move from underwater to above sea level due to an earthquake. • Darwin extended his observations to the evolution of organisms.

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13. KEY CONCEPT Darwin proposed natural selection as a mechanism for evolution.

14. neck feathers crop tail feathers Several key insights led to Darwin’s idea for natural selection. • Darwin noticed a lot of variation in domesticated plants and animals. • Artificial selection is the process by which humans select traits through breeding.

15. 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. • There is a struggle for survival due to overpopulation and limited resources. • Darwin proposed that adaptations arose over many generations.

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17. VARIATION OVERPRODUCTION ADAPTATION DESCENT withMODIFICATION Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. • variation • Fitness is the measure of survival ability and ability to produce more offspring. • overproduction • adaptation • descent with modification

18. five digits wrist bone Natural selection acts on existing variation. • Natural selection can act only on traits that already exist. • Structures take on new functions in addition to their original function.

19. KEY CONCEPT Evidence of common ancestry among species comes from many sources.

20. Evidence for evolution in Darwin’s time came from several sources. • Fossils provide evidence of evolution. • Fossils in older layers are more primitive than those in the upper layers.

21. Section 2 Evidence of Evolution Chapter 15 The Fossil Record, continued • Transitional Species • Fossils of transitional species show evidence of descent with modification.

22. Section 2 Evidence of Evolution Chapter 15 Evidence of Whale Evolution

23. island species most closely resemble nearest mainland species • populations can show variation from one island to another • The study of geography provides evidence of evolution.

24. Larva Adultbarnacle Adult crab • identical larvae, different adult body forms • similar embryos, diverse organisms • Embryology provides evidence of evolution.

26. Molefoot Batwing Human hand • Homologous structures are similar in structure but different in function. • Homologous structures are evidence of a common ancestor. • The study of anatomy provides evidence of evolution.

27. Human hand Mole foot Bat wing Fly wing • The study of anatomy provides evidence of evolution. • Analogous structures have a similar function. • Analogous structures are not evidence of a common ancestor.

28. Structural patterns are clues to the history of a species. • Vestigial structures are remnants of organs or structures that had a function in an early ancestor. • Ostrich wings are examples of vestigial structures.

29. What term describes features that are similar in structure but different in function? • In which rock layer would you expect to find the most primitive fossils?—Top, middle, bottom • The embryos of many kinds of animals have gill slits. Gill slits develop into gills in fish and into ears of mammals. What do these common structures indicate? • Describe analogous structures?

30. KEY CONCEPT New technology is furthering our understanding of evolution.

31. Fossils provide a record of evolution. • Paleontology is the study of fossils or extinct organisms.

32. Paleontology provides evidence to support evolution.

33. Molecular and genetic evidence support fossil and anatomical evidence. • Two closely-related organisms will have similar DNA sequences.

34. no longer function • carried along with functional DNA • can be clues to a common ancestor • Pseudogenes are sequences providing evidence of evolution.

35. control the development of specific structures • found in many organisms • Protein comparisons, or molecular fingerprinting reveals similarities among cell types of different organisms. • Hox genes indicate a very distant common ancestor.

36. Evolution unites all fields of biology. • Scientist from any fields contribute to the understanding of evolution. • The basic principles of evolution are used in many scientific fields.

37. What is a transitional fossil? • What can be learned about evolution from DNA sequencing? • Why is the fossil record incomplete? • Suppose scientists found a fossil of a dinosaur that had feathers. What evolutionary information can be inferred from this fossil?

38. KEY CONCEPT Modern classification is based on evolutionary relationships.

39. Cladistics is classification based on common ancestry. • Phylogeny is the evolutionary history for a group of species. • evidence from living species, fossil record, and molecular data • shown with branching tree diagrams

40. classification based on common ancestry • species placed in order that they descended from common ancestor • Cladistics is a common method to make evolutionary trees.

41. A cladogram is an evolutionary tree made using cladistics. • A clade is a group of species that shares a common ancestor. • Each species in a clade shares some traits with the ancestor. • Each species in a clade has traits that have changed.

42. 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade 4 Diapsida clade 5 Archosauria clade FEATHERS & TOOTHLESS BEAKS. SKULL OPENINGS IN FRONT OF THE EYE & IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID FOUR LIMBS WITH DIGITS DERIVED CHARACTER • Derived characters are traits shared in different degrees by clade members. • basis of arranging species in cladogram • more closely related species share more derived characters • represented on cladogram as hash marks

43. CLADE 1 Tetrapoda clade 2 Amniota clade 3 Reptilia clade 4 Diapsida clade 5 Archosauria clade NODE FOUR LIMBS WITH DIGITS DERIVED CHARACTER • Nodes represent the most recent common ancestor of a clade. • Clades can be identified by snipping a branch under a node. FEATHERS AND TOOTHLESS BEAKS. SKULL OPENINGS IN FRONT OF THE EYE AND IN THE JAW OPENING IN THE SIDE OF THE SKULL SKULL OPENINGS BEHIND THE EYE EMBRYO PROTECTED BY AMNIOTIC FLUID

44. Molecular evidence reveals species’ relatedness. • Molecular data may confirm classification based on physical similarities. • Molecular data may lead scientists to propose a new classification. • DNA is usually given the last word by scientists.

45. What does a cladogram show? • What is true about two organisms that share the same common ancestor? • What is true about the organisms that branch off after a hash mark on a cladogram? • What does a node represent on a cladogram?