Changes in Species

1. Changes in Species 1 Chapter 19 Does evolution occur? Can we prove it? 2 6 min

2. Great Britain Europe North America ATLANTIC OCEAN PACIFIC OCEAN Africa Galápagos Islands Equator South America Australia Andes Cape of Good Hope Tasmania Cape Horn New Zealand Tierra del Fuego Darwin’s Voyages

3. Observations Inference Overproduction of offspring Natural selection: Differential reproductive success Individual variation Darwin’s Natural Selection WITHIN a SPECIES or POPULATION: • Variation exists (mutation, etc.) • Over-reproduction occurs • Competition for resources occurs • Survivors pass on their traits to the next generation -- those traits are“selected” Species: population(s) of successfully interbreeding individuals

4. THUS: • There is “Descent with Modification” • Survival of the Fittest • Differential Survival and Reproduction • A species adapts to environmental change by evolving (migration or extinction are the other choices) NOTE: Individuals do NOT adapt; they live or die • adaptation = structural, biochemical, or behavioral characteristic that helps survival (survive = live & reproduce)

5. 7 min • AND13 • Evolution reduces competition • No two populations have the sameNICHE • Eg. moths & butterflies: avoid competition for nectar by... Competitive Exclusion Principle

6. Natural Selection in Action Population with varied inherited traits 1 Elimination of individuals with certain traits 2 Reproduction of survivors 3 Increasing frequency of traits that enhance survival and reproductive success 4

7. Galapagos finches avoid competition for seeds by...13

8. Cactus ground finch Medium ground finch Small tree finch Medium tree finch Woodpecker finch Large cactus ground finch Large ground finch Small ground finch Gray warbler finch Green warbler finch Large tree finch Vegetarian finch Mangrove finch • Fourteenspecies of Galápagos finches have beak shapes adapted to suit their environ-ments Sharp-beaked ground finch Cactus-flower-eaters Bud-eater Seed-eaters Insect-eaters Tree finches Ground finches Warbler finches Common ancestor from South American mainland Figure 1.13

9. ‘I’iwi13

10. ‘Amakihi13

11. ‘Akohekohe13

12. Palila13

13. ‘Apapane13

14. ‘Akiapola’au13

15. How could little changes… ~ 4 min Add up to something this big?

16. 4 19.1 Fossil Evidence 7 min Paleontology – study of ancient things Fossils: the evidence of an organism preserved in rock, ice, amber, tar, peat, or volcanic ash. Generally, bones and hard body parts are best preserved. . 3 ~1 in 10,000 species found 5

17. In the side of a cliff is the story of evolution… Palo Duro Canyon, TX7 Younger rock is closer to the top You can see what organisms lived when and how organisms changed through the years. 6

18. Figure 1.10

19. Evolution of the Horse9 Look at the gradual changes in hoof structure as well as size and shape over time… Is this macroevolution or microevolution?

20. Burgess Shale8 Cambrian Era ~ 500 MYA Mostly invertebrate animal life First fishes beginning to appear Fossils formed in fine mud – very detailed Animals of that era are ancestors of modern animals Wiwaxia corrugata Waptia fieldensis - crab Marrella splendens -arthropod

21. Archaeopteryx The search for missing links like between birds and dinosaurs. Wing claw (like reptile) Teeth (like reptile) Feathers Long tail with many vertebrae (like reptile)

22. Coevolution: two species interacting and influencing each others’ evolution Homologies: similarity of structure resulting from common ancestor 19.2 Evidence from Ecology 14 • “Yucca flowers are a certain shape so only that tiny moth can pollinate them. The moths lay their eggs in the yucca flowers and the larvae (caterpillars) live in the developing ovary and eat yucca seeds.”14 12 Gene Sequences, too!

23. 19.4 The Process of Speciation Mechanism: reproductive isolation(via pre or postzygotic mechanisms) • Populations become reproductively isolated, preventing interbreeding. • Allele frequencies of the two gene pools diverge • Populations can no longer inter-breed and produce fertile offspring Post-zygotic barriers Pre-zygotic barriers • Hybrid inviability • Temporal isolation • Hybrid sterility • Habitat isolation • Behavioral isolation Gametes Viable, fertile offspring • Mechanical isolation • Gametic isolation

24. Remember Darwin’s Finches?They evolved throughAdaptive Radiation(Divergent Evolution)23 modern species are believed to have evolved from a single ANCESTRAL species, filling various niches See P. 511 13 Common ancestor

25. Geographic Isolation17 Organisms that can’t come into contact can’t breed --- Microevolution produces differences… Eventually, the populations can’t breed even if they meet again.

26. Ecological Isolation17 • When species adapt to different environments • Via microevolution --- and interbreeding stops.

27. And then… the next banana 4 min

28. Behavioral Isolation18 If you’re not doing the right dance and singing the right song, you don’t get a mate!

29. Seasonal Isolation Northern Leopard Frogs19 Mating Season starts in late April21 Southern Leopard Frogs20 Mating Season starts in March

30. Mechanical Isolation17 Could be for structural reasons, wrong chromosome numbers, or non-functional zygotes/infertile offspring even if mating occurs. Horse20 + Donkey21 = Mule or Hinny22 (2n = 63)

31. Isolation via Polyploidy • Originate from accidents during cell division • Can lead to speciation Hybrid (usually sterile; chromosomes cannot pair during meiosis) Gametes n = 5 Gametes n = 2 Fertile hybrid 2n = 10 Species A 2n = 4 Self- fertilization Meiosis Mitotic error produces polyploid condition 2n = 10 n = 5 n = 3 Species B 2n = 6 Figure 14.12

32. Origin of Wheat Triticum monococcum (14 chromosomes) Wild Triticum (14 chromosomes) 1 Sterile hybrid (14 chromosomes) Cell division error; self-fertilization 2 T. tauschii (wild) (14 chromosomes) T. turgidum Emmer wheat (28 chromosomes) 3 Speciation can take eons, but with polyploidy… Sterile hybrid (21 chromosomes) Cell division error; self-fertilization 4 T. aestivum Bread wheat (42 chromosomes)

33. Speciation occurs faster with Small Populations Artificial Selection -- induced mutations, genetic engineering, selective breeding • Gradualism • Punctuated Equilibrium There are 2 Models Remember – Individuals do NOT evolve – Populations do!

34. 12 When has a population changed enough to be called a new species?

35. Or in rare cases, Stasis may occur where nothing changes for a long time. 15 The coelacanth (lobe-finned fish) has remained basically unchanged for millions of years. 15

36. Sources Cited 1. naturecoast.com/ hobby/mv20.htm 2. www.oceansonline.com/ charles_darwin.htm 3. pubs.usgs.gov/gip/continents/ 4. www.idsos.state.id.us/ elect/emblem.htm 5. http://www.amberscapes.com/Fossil_Amber_Gallery/Fossil_Amber_Gallery_Insects/Plant_hopper/Plant_hopper.htm 6. http://www.clearlight.com/~mhieb/WVFossils/GeolTimeScale.html. 7. http://bcornet2.homestead.com/files/esotri681.htm 8. http://www.nmnh.si.edu/paleo/shale/index.html 9. www.ecotao.com/holism/ glosae.htm 10. http://www.aw.com/bc/info/campbell6e/C6eCIPLSampler/ImageLibrary/HTML/source/1.html 11. www.answersingenesis.org/news/ scientific_american.asp12. BioCD. From Biology, Fifth Edition. Campbell, Reece, Mitchell. Addison, Wesley, Longman. 1999. 13. From R. Warehime 14. biology.clc.uc.edu/courses/ bio303/coevolution.htm 15. students.washington.edu/matthewr/ zoo451/introduction.html 16. www.amnh.org/naturalhistory/ 0501/0501_pick.html 17. http://evolution.berkeley.edu/evosite/history/speciation2.shtml 18. cas.bellarmine.edu/ tietjen/images/speciation.htm 19. http://www.amazilia.net/images/Herps/Frogs/NorthernLeopardFrog.htm 20. http://www.fcps.k12.va.us/StratfordLandingES/Ecology/mpages/southern_leopard_frog.htm 21. http://wlapwww.gov.bc.ca/wld/frogwatch/whoswho/factshts/northlep.htm 22. waynesword.palomar.edu/ hybrids1.htm Unlabeled Pictures are from the PowerPoint CD for Essential Biology with Physiology. 2006.