Structural similarities among organisms. Geographic distribution of organisms.

1. S&T: 3 pg. 310 give examples of types of evidence that Darwin gathered to develop the theory of evolution; • Structural similarities among organisms. • Geographic distribution of organisms. • The embryological similarities among organisms. • The pattern of organism groupings. • The direct observation of evolutionary changes in the laboratory and in the wild. • The molecular similarities among organisms- were found after Darwin (more to come ). 7.Transitional species found in fossil record.-bonus

2. Evidence for Evolution

4. Key Idea • Evidence for evolution comes from many sources. • Fossils • Vestigial structures • Biogeography • Homologous structures • Embryology • DNA/protein sequences

5. Fossils • Fossils provide evidence of evolution. • Fossils in older layers are more primitive than those in the upper layers. • Extinct Fossils resemble modern animals. This shows a common ancestry.

7. Dating Fossils • Relative dating estimates the time during which an organism lived. • It compares the placementof fossils in layers of rock. • Scientists infer the order inwhich species existed.

8. Transitional species found in fossil record – fish-amphibian (Tiktaalik) • 375 million years old • Discovered in Canada in 2004

9. Transitional fossil: bird/reptileArchaeopteryx150 million yrs old.7 specimens found

10. Fossil Evidence for Whale Evolution Whale Video

11. 2. Vestigial Structures • Vestigial structures are remnants of organs or structures that had a function in an early ancestor. • Examples include ostrich wings, human appendix, and wisdom teeth, whale and snake pelvis/hind legs.

13. Pythons have tiny femurs (leg bone)

14. 3. Biogeography Biogeography: the study of past and present distribution of species. • 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

15. 4. Homologous Structures • Homologous structures- Similar anatomical features that originated in a shared ancestor. • Homologous structures are similar in structure but may be different in function.

17. Human hand Mole foot Bat wing Fly wing Homologous Structures vs. Analogous Structures • Analogous structures have a similar function. • Analogous structures are not evidence of a common ancestor.

18. Analogous Structures • look similar on the outside • same function • different structure & development on the inside • different origin • no evolutionary relationship • Solving a similar problem with a similar solution

19. Homologies: at the cellular level Review from IS 1: What cellular structures are shared by all eukaryotic organisms?

20. 5. Embryology • Embryology-studying the early stages of development of an organism (inside the womb or inside the egg)

21. all vertebrate embryos have a “gill pouch” at one stage of development

23. Hox genes control body development in many organisms. They help control head to tail organization.

24. 6. DNA/Protein Sequences • Two closely-related organisms will have similar DNA, RNA, and protein (amino acid) sequences. • This also gives evidence of a common ancestor.

25. Dog Human Macaque Bird Frog Lamprey 8 32 45 125 67 0 10 20 30 40 50 60 70 80 90 100 110 120 • Comparing DNA & protein structure • everyone uses the same genetic code! • DNA • compare common genes • compare common proteins number of amino acids different from human hemoglobin

26. DNA (cont) • DNA code itself is a homology that links all life on Earth to a common ancestor. • In some cases, if we were to transfer genetic material from the cell of one living thing to the cell of another, the recipient would follow the new instructions as if they were its own. • Useful in genetic engineering

27. GFP traditionally refers to the protein first isolated from a gene found in thejellyfishAequoreavictoriawhich glows in the dark. • This gene can be transferred to other organisms which will express this same trait

28. GloFish, the first genetically modified animal to be sold as a pet

29. Building “family” trees - Phylogenies Closely related species are branches on the tree — coming from a common ancestor

31. Cladograms • diagram that depicts evolutionary relationships among groups. • based on PHYLOGENY, which is the study of evolutionary relationships. • Uses traits/characteristics that are common between organisms to organize them

33. You try: Match each point on the cladogram with the trait. 1. ______ Wings2. ______ 6 Legs3. ___ Segmented Body4. ___ Double set of wings5. ____ Jumping Legs6. __ Crushing mouthparts7. ____ Legs8. ______ Curly Antennae

34. Phylogenetic trees • Very similar to a cladogram • Tends to use genetic information and physical traits to construct • Root of the tree represents the ancestral lineage, and the tips of the branches represent the descendants of that ancestor. • As you move from the root to the tips, you are moving forward in time.

35. Speciation • Species: a group of organisms that can interbreed in nature • Speciation: When two groups of organisms can no longer interbreed – they have become too different through evolution

36. When a lineage splits (speciation – forming a new species), it is represented as branching on a phylogeny. When a speciation event occurs, a single ancestral lineage gives rise to two or more daughter lineages.

37. Phylogenies trace patterns of shared ancestry between lineages. Each lineage has a part of its history that is unique to it alone and parts that are shared with other lineages.

38. Each lineage also has ancestors that are unique to that lineage and ancestors that are shared with other lineages — common ancestors • Nodes represent common ancestors