Table of Contents

1. Table of Contents Chapter Preview 7.1 Darwin’s Theory 7.2 Evidence of Evolution 7.3 Evolution of Species 7.4 Classifying Organisms 7.5 Branching Trees

2. Chapter 7 Preview Questions • Compared to body cells, the cells that result from meiosis have • half the number of chromosomes. • the same number of chromosomes. • double the number of chromosomes. • triple the number of chromosomes.

3. Chapter 7 Preview Questions • Compared to body cells, the cells that result from meiosis have • half the number of chromosomes. • the same number of chromosomes. • double the number of chromosomes. • triple the number of chromosomes.

4. Chapter 7 Preview Questions • 2. Which is true of the alleles for a gene? • There are only two alleles for every gene. • The alleles are always identical. • The alleles are never identical. • One allele may be dominant.

5. Chapter 7 Preview Questions • 2. Which is true of the alleles for a gene? • There are only two alleles for every gene. • The alleles are always identical. • The alleles are never identical. • One allele may be dominant.

6. Chapter Preview Questions • 3. An organism’s traits are determined by its • carbohydrates. • DNA. • mitochondria. • chloroplasts.

7. Chapter Preview Questions • 3. An organism’s traits are determined by its • carbohydrates. • DNA. • mitochondria. • chloroplasts.

8. Chapter 7 Preview Questions • 4. Where do sexually reproducing organisms inherit their alleles from? • half from each parent • mostly from their mother • mostly from their father • only from their mother

9. Chapter 7 Preview Questions • 4. Where do sexually reproducing organisms inherit their alleles from? • half from each parent • mostly from their mother • mostly from their father • only from their mother

10. Changes Over Time Section 7.1:Darwin’s Theory What important observations did Darwin make on his voyage? How did Darwin account for the diversity of species and the differences between similar species? How does natural selection lead to evolution?

11. CHARLES DARWIN

12. Changes Over Time Darwin’s Voyage • Charles Darwin sailed on the HMS Beagle --1831 • England to the Galápagos Islands. • He was the ships naturalist • 5 years

13. Darwin's Discoveries Finches had beaks adapted to their diet Mainland Iguanas had short claws Those on the islands had long claws

14. The Galapagos cormorant had lost its ability to fly The shells of the tortoise differed between the islands.

15. The Theory of Natural Selection In 1859 ----Darwin proposed his theory of evolution based on the idea of natural selection. Natural Selection= the strongest or most fit survive

16. Changes Over Time Overproduction and Variation • Overproduction is when an organism produces too many offspring to increase the chance of survival .

17. Overproduction and Variation • Variation is when offspring have differences . • Each individual that is born will have different characteristics. • These characteristics are heritable

18. Changes Over Time Competition and Selection • Variations among animals can give them traits that can help them survive and reproduce.

19. Section 7.2:Evidence of Evolution What evidence supports the theory of evolution? How do fossils form? What do scientists learn from fossils?

20. Homologous Structures • Homology is when bones are similar in different organisms.

21. HOMOLOGOUS STRUCTURES Homologous structures are one piece of evidence scientists use to prove evolution

22. FOSSILES ARCHIOPTERIX- the first bird

23. TRILOBITES Index fossils that were alive a short time

24. How Do Fossils Form? • Most fossils form when organisms that die become buried in sediments.

25. Changes Over Time • The fossils record provides evidence about … • past live forms • past environment. • rate at which evolution occurred

26. Section 7.3:Evolution of Species What factors have contributed to the diversity of species? How do new species form? How do scientists infer evolutionary relationships among species? What causes the extinction of species?

27. Kaibab and Albert's Squirrels • These two kinds of squirrels have been isolated from one another for a long time. • Isolation may result in two different species.

28. A Branching Tree • This branching tree shows how scientists now think that raccoons, lesser pandas, giant pandas, and bears are related.

29. Extinction of Species Extinction is caused by a change in species' environment.

30. Section 7.4:Classifying Organisms Why do biologists organize living things into groups? What do the levels of classification indicate about the relationship between organisms? What characteristics are used to classify organisms into domains and kingdoms?

31. Levels of Classification • As you move down the levels of classification, the number of organisms decreases. The organisms at lower levels share more characteristics with each other.

32. Three Domains of Life • In the three-domain system of classifications, all known organisms belong to one of three domains–Bacteria, Archaea, or Eukarya. Bacteria ArchaeaEukarya Protists Fungi Plants Animals

33. Bacteria • Single celled • No nucleus • prokaryotes

34. Archaea • Single celled • No nucleus • Prokaryotes • Ancient

35. Eukarya. • Have a nucleus • Third domain

36. The kingdoms

37. Section 5:Branching Trees How does a branching tree diagram show evolutionary relationships?

38. A Branching Tree • Branching trees show relationships between groups of organisms. • It also shows the order in which specific characteristics may have evolved.

39. Shared Derived Characteristics • A branching tree diagram shows evolutionary relationships by grouping organisms according to shared derived characteristics. Reptiles Amphibians Fishes Egg with shell Invertebrates Four limbs Backbone Ancestor of animals