1. Chapter 22 – Descent with Modification AP BIOLOGY – BRETHREN CHRISTIAN HS MS. WHIPPLE

2. 1. Who is Charles Darwin? Describe how the events of his life contribute to his development of the theory of Natural Selection?  Charles Darwin (1809–1882) was born in western England.  As a boy, he developed a consuming interest in nature.  When Darwin was 16, his father sent him to the University of Edinburgh to study medicine.  Darwin left Edinburgh without a degree and enrolled at Cambridge University with the intent of becoming a clergyman.  At that time, most naturalists and scientists belonged to the clergy and viewed the world in the context of natural theology.  Darwin received his B.A. in 1831. Section 22.2

3. 1. Who is Charles Darwin? Describe how the events of his life contribute to his development of the theory of Natural Selection?  After graduation Darwin joined the survey ship HMS Beagle as ship naturalist and conversation companion to Captain Robert FitzRoy.  FitzRoy chose Darwin because of his education, and because his age and social class were similar to that of the captain.  Field research helped Darwin frame his view of life.  The primary mission of the five-year voyage of the Beagle was to chart poorly known stretches of the South American coastline.  Darwin had the freedom to explore extensively on shore while the crew surveyed the coast.  He collected thousands of specimens of the exotic and diverse flora and fauna of South America. Section 22.2

4. 1. Who is Charles Darwin? Describe how the events of his life contribute to his development of the theory of Natural Selection?  Darwin noted that the plants and animals of South America were very distinct from those of Europe.  Organisms from temperate regions of South America more closely resembled those from the tropics of South America than those from temperate regions of Europe.  Further, South American fossils, though different from modern species, more closely resembled modern species from South America than those from Europe.  While on the Beagle, Darwin read Lyell’s Principles of Geology.  He experienced geological change firsthand when a violent earthquake rocked the coast of Chile, causing the coastline to rise by several feet.  He found fossils of ocean organisms high in the Andes and inferred that the rocks containing the fossils had been raised there by a series of similar earthquakes.  These observations reinforced Darwin’s acceptance of Lyell’s ideas and led him to doubt the traditional view of a young and static Earth. Section 22.2

5. 1. Who is Charles Darwin? Describe how the events of his life contribute to his development of the theory of Natural Selection?  Darwin’s interest in the geographic distribution of species was further stimulated by the Beagle’s visit to the Galapagos, a group of young volcanic islands 900 km west of the South American coast.  Darwin was fascinated by the unusual organisms found there.  After his return to England, Darwin noted that while most of the animal species on the Galapagos lived nowhere else, they resembled species living on the South American mainland.  He hypothesized that the islands had been colonized by plants and animals from the mainland that had subsequently diversified on the different islands. Section 22.2

6. Fig. 22-5 NORTH AMERICA EUROPE AFRICA AUSTRALIA GREAT BRITAIN SOUTH AMERICA ATLANTIC OCEAN PACIFIC OCEAN Cape of Good Hope Tierra del Fuego Cape Horn Tasmania New Zealand Andes Equator The Galápagos Islands Pinta Marchena Genovesa Santiago Daphne Islands Pinzón Fernandina Isabela San Cristobal Santa Fe Santa Cruz Florenza Española Section 22.2

7. 2. What are adaptations? How did the observation of these adaptations help Darwin develop his theory?  In reassessing his observations, Darwin perceived adaptation to the environment and the origin of new species as closely related processes  From studies made years after Darwin’s voyage, biologists have concluded that this is indeed what happened to the Galápagos finches Section 22.2

8. Fig. 22-6 (a) Cactus-eater(c) Seed-eater (b) Insect-eater Section 22.2

9. 3. What is the theory of Natural Selection as explained by Darwin?  A process in which individuals that have certain inherited traits tend to survive and reproduce at higher rates than other individual because of those traits (or the interaction of traits) Section 22.2

10. 4. Describe your understanding of Descent with Modification?  Darwin developed two main ideas:  Descent with modification explains life’s unity and diversity  Natural selection is a cause of adaptive evolution  The phrase descent with modification summarized Darwin’s perception of the unity of life  The phrase refers to the view that all organisms are related through descent from an ancestor that lived in the remote past  In the Darwinian view, the history of life is like a tree with branches representing life’s diversity  Darwin’s theory meshed well with the hierarchy of Linnaeus (Taxonomy) Section 22.2

11. Fig. 22-8 Hyracoidea (Hyraxes) Sirenia (Manatees and relatives) Moeritherium Barytherium Deinotherium Mammut Elephas maximus (Asia) Stegodon Mammuthus Loxodonta africana (Africa) Loxodonta cyclotis (Africa) 0 10 4 2 5.5 24 34 Millions of years ago Years ago Platybelodon Section 22.2

12. 5. Scientists estimate that over ______________ of all species that have ever lived are now extinct.  98% of all species that have ever lived are now extinct. WAY TO GO HUMANS…we made the 2% still living!! Section 22.2

13. 6. What is Artificial Selection? Give me one example.  Darwin noted that humans have modified other species by selecting and breeding individuals with desired traits, a process called artificial selection  Dogs, Broccoli, Corn, Bananas, Cows, Chickens, Turkeys, Horses, Pigs, Donkeys, Cauliflower, Mice, Apples, Oranges, Cats, Guinea Pigs, Hamsters, Potatoes, Carrots, Brussel Sprouts…so many more!!! Section 22.2

14. Fig. 22-9 Kale Kohlrabi Brussels sprouts Leaves Stem Wild mustard Flowers and stems Broccoli Cauliflower Flower clusters Cabbage Terminal bud Lateral buds Brassica olerasia var. capitata var. gemmifera var. acephala var. botrytis var. italicavar. gogylodes Section 22.2

15. 7. Write your understanding of Darwin’s two observations and two inferences.  Observation #1: Members of a population often vary greatly in their traits.  Observation #2: All species can produce more offspring than their environment can support and many of these offspring fail to survive and reproduce.  Inference #1: Individuals whose inherited traits give them a higher probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals  "The higher chances of survival, the more offspring they have"  Inference #2: This unequal ability of individuals to survive and reproduce will lead to the accumulation of favorable traits in the population over generations  "Those that survive will bring the favorable traits with them" Section 22.2

16. Fig. 22-UN1 Observations Over time, favorable traits accumulate in the population. Inferences and Individuals in a population vary in their heritable characteristics. Organisms produce more offspring than the environment can support. Individuals that are well suited to their environment tend to leave more offspring than other individuals The End

17. 8. What is meant by the phrase “Individuals do not evolve, populations do”  Individuals do not evolve; populations evolve over time  Natural selection can only increase or decrease heritable traits in a population. Each individual is stuck with the heritable traits (genes) they were born with, an individual cannot generally change their genes over their lifetime.  Adaptations vary with different environments Section 22.2

18. 1. Explain how rapid evolution was shown with the Soapberry bugs of in central and southern Florida.  Native to southern US  In Florida, native host plant is balloon vine  which occurs primarily on southern tip of Florida, on the Florida Keys, and less commonly, in central Florida  Bugs feed by piercing the fruit with beak and inserting it into the seeds  Flat-podded golden rain tree introduced to central Florida in 1926  This new Rain tree fruits are much thinner than balloon vine fruits.

19.  Soapberry bugs in Central Florida started using rain trees as a host plant  Populations of bugs living on thin-fruited rain trees evolved shorter beaks  Soapberry bugs in c. Florida started using rain trees as a host plant  Populations of bugs living on thin-fruited rain trees evolved shorter beaks 1. Explain how rapid evolution was shown with the Soapberry bugs of in central and southern Florida.

20. Fig. 2.1(a) Evolutionary change in soapberry bugs

21. Fig. 2.1(b) Evolutionary change in soapberry bugs

22. 2. How do drug-resistant pathogens show ongoing Natural Selection in our society?  Antibiotic resistance is an evolutionary phenomenon of tremendous clinical significance.  Early in the 20 th century, a variety of antibiotics, used to treat bacterial diseases, were developed.  An understanding of evolution is helpful to understand where these antibiotics come from to begin with…many, such as penicillin, were evolved by fungi, over millions of years, to kill off their bacterial competitors.  Humans have co-opted them for our own purposes.  Since the 20 th century, the bacterial pathogens have evolved resistance to our antibiotics, because extensive use of these drugs has caused very strong natural selection in favor of mutations which favor antibiotic resistance.  For instance, many MRSA strains are resistant to many common antibiotics.

23. 3. Describe your understanding of the following key concepts of Natural Selection:  “Natural selection is a process of editing, not a creative mechanism”  “Natural selection depends on time and place”

24. 4. What is Homology ? How is this used in the study of evolution?  Homology is similarity resulting from common ancestry  Studying Homology can give us insight into evolutionary relationships between organisms.

25. 5. What are Homologous Structures ? How is the mammalian forearm an example?  Homologous structures are anatomical resemblances that represent variations on a structural theme present in a common ancestor

26. Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Humerus Radius Ulna Carpals Metacarpals Phalanges HumanCatWhaleBat 5. What are Homologous Structures ? How is the mammalian forearm an example?

27.  EXTRA!! Comparative embryology reveals anatomical homologies not visible in adult organisms Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pharyngeal pouches Post-anal tail Chick embryo (LM)Human embryo

28. 6. What are Vestigial Structures ? What are two examples.  Vestigial structures are remnants of features that served important functions in the organism’s ancestors.  Some examples are the leg bones in a whales hind end and possibly the human appendix.

29. 7. What is an evolutionary tree ? How is this made?  The Darwinian concept of an evolutionary tree of life can explain homologies  Evolutionary trees are hypotheses about the relationships among different groups  Evolutionary trees can be made using different types of data, for example, anatomical and DNA sequence data

30. Fig. 22-19 Hawks and other birds Ostriches Crocodiles Lizards and snakes Amphibians Mammals Lungfishes Tetrapod limbs Amnion Feathers Homologous characteristic Branch point (common ancestor) Tetrapods Amniotes Birds 6 5 4 3 2 1

31. 8. What is Convergent Evolution ? Give me one example.  Convergent evolution is the evolution of similar, or analogous, features in distantly related groups  Analogous traits arise when groups independently adapt to similar environments in similar ways  Convergent evolution does not provide information about ancestry

32. 9. Describe Analogous Structures. Give me one example.  Analogous structures are structures that have the same function but not the same evolutionary descent.

33. Fig. 22-20 Sugar glider Flying squirrel AUSTRALIA NORTH AMERICA

34. 10. Describe the evidence for evolution that comes from Biogeograpy ? What is Pangea ?  Darwin’s observations of biogeography, the geographic distribution of species, formed an important part of his theory of evolution  Islands have many endemic species that are often closely related to species on the nearest mainland or island  Earth’s continents were formerly united in a single large continent called Pangaea, but have since separated by continental drift  An understanding of continent movement and modern distribution of species allows us to predict when and where different groups evolved

35. 11. Endemic species in an area are:  An Endemic Species is one that is only found in that region and nowhere else in the world.

36. Sources:  http://jan.ucc.nau.edu/~pservice/bio435_660/bio435_660_chap2.ppt http://jan.ucc.nau.edu/~pservice/bio435_660/bio435_660_chap2.ppt  http://www.google.ca/url?sa=t&rct=j&q=&source=web&cd=1&ved=0CB8 QFjAA&url=http%3A%2F%2Fwww.uic.edu%2Fclasses%2Fbios%2Fbios101%2F Evidence%2520for%2520Evolution.ppt&ei=NbX4VMyFIoHuoATTrYHACw&us g=AFQjCNHesK8-Zaq9ubm0UFOI2_jwrlArHg&bvm=bv.87611401,d.cGU http://www.google.ca/url?sa=t&rct=j&q=&source=web&cd=1&ved=0CB8 QFjAA&url=http%3A%2F%2Fwww.uic.edu%2Fclasses%2Fbios%2Fbios101%2F Evidence%2520for%2520Evolution.ppt&ei=NbX4VMyFIoHuoATTrYHACw&us g=AFQjCNHesK8-Zaq9ubm0UFOI2_jwrlArHg&bvm=bv.87611401,d.cGU