DESCENT WITH MODIFICATION A Darwinian View of Life

DESCENT WITH MODIFICATION A Darwinian View of Life AP BIOLOGY Chapter 19 Image from: Biology by Miller and Levine; Prentice Hall Publishing© 2006

WHO INFLUENCED DARWIN’S THINKING Linnaeus (classification) Hutton (gradual geologic change) Lamarck (species can change) Malthus (population limits) Cuvier (fossils, extinction) Lyell (modern geology) Darwin (evolution, nutural selection) Mendel (inheritance) American Revolution 1750 Wallace (evolution, natural selection) French Revolution U. S. Civil War 1800 1850 1900 1795 Hutton proposes his theory of gradualism. 1798 Malthus publishes “Essay on the Principle of Population. ” 1809 Lamarck publishes his theory of evolution. 1830 Lyell publishes Principles of Geology. 1831– 1836 Darwin travels around the world on HMS Beagle. 1837 Darwin begins his notebooks on the origin of species. 1844 Darwin writes his essay on the origin of species. 1858 Wallace sends his theory to Darwin. 1859 The Origin of Species is published. 1865 Mendel publishes inheritance papers. Figure 22. 2 Image from: AP BIOLOGY by Campbell and Reece

Image from: http: //www. ucmp. berkeley. edu/history/aristotle. html Aristotle- (384 -322 B. C. ) Species are fixed (unchanging) BUT recognized similarities Arranged life forms on a scale of increasing complexity scala natura“scale of nature” http: //www. kheper. net/topics/greatchainofbeing/index. html

Image from: http: //www. medusozoa. com/images/linnaeus. jpg • Founder of TAXONOMY-1735 Science of grouping & naming • Sought to discover order in the diversity of life “for the greater glory of God” (1707 -1778) • Each creature was special. NO evolutionary link • Devised classification system based on morphology (form and structure) Binomial Nomenclature: Naming system that gives organisms a two part scientific name- Genus species Still used today

LINNAEUS’S SYSTEM Nested hierarchy Taxon = classification unit to which organisms are assigned Ex: Panthera is a taxon at the genus level Mammalia is a taxon at the class level http: //content. answers. com/main/content/wp/en-commons/thumb/d/d 6/150 px-Biological_classification_L_Pengo. svg. png

Kidspiration by Riedell Image Sources: see end of show

Kids Prefer Cheese Over Fried Green Spinach Kings Play Chess On Fat Green Stools King Phillip Cried Oh For Goodness Sake! Kingdom Animalia Phylum Chordata Class Mammalia Order Carnivora Family Felidae Genus Panthera Species leo http: //www. vetmed. wisc. edu/dms/fapm/personnel/tom_b/2004 -lion. jpg

GENUS = group of closely related species GENUS = Ursus (Includes many kinds of bears) Ursus arctos Ursus maritimus Ursus americanis SPECIES = unique to each kind of bear http: //www. macecanada. com/images/bears/kodiak_bear. gif http: //students. cs. byu. edu/~tole/Virtual%20 Zoo/polar-bear. jpg http: //en. wikipedia. org/wiki/Image: Black_bear_large. jpg

Genus and species assignments provide 2 part scientific name Homo sapiens Image from: http: //www. earlylearning. ubc. ca/images/photo_baby. jpg

Modern Taxonomy has added more Kingdoms AND more levels (DOMAINS) Linneaus only used 2 kingdoms (Plants & Animals) Domains are larger than Kingdoms and are based on the differences in ribosomal RNA

Ideas that shaped Darwin’s thinking: http: //upload. wikimedia. org/wikipedia/commons/2/28/Georges_Cuvier. jpg George Cuvier – Father of Paleontology ANTI-EVOLUTONIST Fossils are remains of extinct life forms “CATASTROPHISM” boundaries represent floods, droughts, etc. that destroyed many species living at that time

Ideas that shaped Darwin’s thinking: http: //www. creationism. org/books/Taylor. In. Minds. Men/Taylor. IMMc 03. htm 1795 –James Hutton “GRADUALISM” Profound changes can result from cumulative effect of slow but continuous processes Proposed that the Earth was shaped by geological forces occurring over very long periods of time, and is MILLIONS not THOUSANDS of years old.

Ideas that shaped Darwin’s thinking: 1833 -Charles Lyell Incorporated Hutton’s ideas into “UNIFORMITARIANISM” Geological processes that shaped Earth are still operating at same rate. Darwin read his book on the Beagle voyage http: //www. biologydaily. com/biology/Sir_Charles_Lyell

MODERN GEOLOGY http: //wrgis. wr. usgs. gov/docs/usgsnps/animate/A 08. gif

http: //www. nndb. com/people/250/000024178/malthus. jpg Ideas that shaped Darwin’s thinking: Thomas Malthus (1798) wrote essay on population growth Human suffering (disease, famine, homelessness, and war) are consequences to human population increasing faster than food and other resources

http: //www. educa. rcanaria. es/fundoro/00. corsi. htm Ideas that shaped Darwin’s thinking: Jean Baptiste Lamarck (1744 -1829) One of first scientists to recognize that living things changed over time and that all species were descended from other species. 1809 - Published his ideas about “Inheritance of Acquired Characteristics” the year Darwin was born

INHERITANCE OF ACQUIRED CHARACTERISTICS The male fiddler crab uses its front claw to attract mates and ward off predators. “USE or DISUSE” = Use it or lose it Through repeated use, the front claw becomes larger. The fiddler passes on this acquired characteristic to its offspring

http: //www. geocities. com/arnold_schwarzenegger_pictures/ What’s wrong with Lamarck’s hypothesis? Lamarck didn’t know about genes and how traits are inherited. Acquired traits are not passed on to offspring Or are they? . . . New field of EPIGENETICS is exploring this

What’s right with Lamarck’s hypothesis? Lamarck was first to develop a scientific hypothesis about evolution and recognize that organisms are adapted to their environment http: //pegasus. cc. ucf. edu/~he 599900/giraffeeating. jpg

Slide by Kim Foglia@ http: //www. explorebiology. com/

Who Was Charles Darwin? In 1831, 22 -year old Charles Darwin left England as naturalist aboard the HMS Beagle for 5 year voyage around the world. Mission: Chart the South American coastline Darwin noticed plants and animals were different from those he knew in Europe Wrote thousands of pages of observations and collected vast number of specimens http: //www. solarnavigator. net/history/explorers_history/HMS_Beagle. jpg

Who Was Charles Darwin? Darwin spent a month observing life on the Galapagos Islands Each island has different rainfall and vegetation and its own unique assortment of plant and animal species. Biology by Miller and Levine; Prentice Hall Publishing© 2006 http: //mikebaird. com/ecuador/images/galapagos_off_ecuador_ng_map. jpg

Who Was Charles Darwin? Although animals on Galapagos resemble species on the South American mainland, many species were found no where else in the world = ENDEMIC http: //www. darwinadventure. com/pictures/galapagos_giantortoise. jpg http: //www. destination 360. com/south-america/ecuador/galapagos-animals. php http: //www. photoseek. com/galapago. html

DARWIN’S FINCHES Darwin collected 14 species of finches and hypothesized that the Galapagos had be colonized by organisms from the mainland that had then diversified on the various

Who Was Charles Darwin? After Darwin returned to England in 1836, he spent years examining specimens he brought back from voyage and filling notebooks with his ideas. He did not rush to publish his ideas because they disagreed with the fundamental scientific views of his day. In 1844 he wrote an essay describing his ideas and asked his wife to publish it if he died. http: //www. elsie. brandeis. edu/images/journals. gif

In 1858 Alfred Russel Wallace, another Naturalist working in the West Indies, wrote an essay describing his work that summarized the same ideas Darwin had been thinking about for 25 years! http: //www. thesecondevolution. com/wallace&darwin. jpg

Suddenly Darwin had incentive to publish the results of his work! In 1859 On the Origin of Species by Means of Natural Selection presented evidence and proposed a mechanism for evolution that he called NATURAL SELECTION http: //www. loc. gov/exhibits/world/images/s 125. jpg

Darwin’s Theory of Evolution Darwin Presents his Case Image from: Biology by Miller and Levine; Prentice Hall Publishing© 2006

Isn’t evolution “just a theory”? In every day usage “theory” often refers to a hunch or a speculation. When people say, “I have a theory about what happened, ” they are often drawing a conclusion based on fragmentary or inconclusive evidence. The formal scientific definition of “theory” is quite different from the every day meaning. It refers to a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence. http: //evolution. berkeley. edu/evosite/evohome. htm

Isn’t evolution just a theory? In Science a theory is a well supported, testable explanation of phenomena that have occurred in the natural world. Example: Cell theory Atomic theory Gravitational theory http: //www. avgoe. de/Star. Child/DOCS/STARCH 00/questions/apple_falling. gif http: //sixthsense. osfc. ac. uk/chemistry/atomic_structure 2/atom. gif

VOCAB ADAPTATION- Any inherited characteristic that increases an organism’s chance of survival http: //www. wildlife-traps. com/skunks. html http: //www. atomtigerzoo. com/photos/images/20060421233733_duckfeet. jpg http: //www. 3 kitty. org/travelrama/Photos/123 -21 -4 x 6. jpg

WHAT IS DARWIN’S THEORY? OVERPRODUCTION of OFFSPRING Capacity to over-reproduce seems characteristic of all species. http: //www. biospheres. com/photogallery 2 ag/images/ladybugs_jpg. jpg http: //atthecreation. com/DEER/too. many. deer. jpg

WHAT IS DARWIN’S THEORY? STRUGGLE FOR EXISTANCE means that members of each species must compete for food, space, and other resources. http: //www. wasatchcomputers. net/gallery/elk_fight. jpg

WHAT IS DARWIN’S THEORY? GENETIC VARIATION is found naturally in all populations Image from www. biologyzone. com http: //www 3. nationalgeographic. com/animals/images/primary/zebra-herd. jpg

WHAT IS DARWIN’S THEORY? Some organisms in a population are less likely to survive. http: //www. cartoonstock. com/newscartoons/cartoonists/rrs/lowres/rrsn 69 l. jpg

VOCAB Ability of an individual to survive and reproduce in its specific environment = FITNESS http: //www. cartoonstock. com/newscartoons/cartoonists/cga/lowres/cgan 170 l. jpg

WHAT IS DARWIN’S THEORY? SURVIVAL OF THE FITTEST = Organisms which are better adapted to their environment tend to produce more offspring than organisms without those traits. http: //www. poster. net/bedard/bed 202. jpg

WHAT IS DARWIN’S THEORY? Over time, NATURAL SELECTION results in changes in the inherited characteristics of a population. These changes increase a species’ fitness in its environment.

IMPORTANT TO REMEMBER ! • POPULATIONS evolve NOT INDIVIDUALS. • NATURAL SELECTION only works on heritable traits. • A trait that is favorable in one environment may be useless or detrimental in another.

WHAT IS DARWIN’S THEORY? DESCENT WITH MODIFICATION suggests that each species has descended with changes from other species over time. This idea suggests that all living species are related to each other and that all species, living and extinct, share a common ancestor.

http: //groups. wfu. edu/Model. UN/images/Cover/Oranges. jpg http: //www. fx. clemson. edu/~ablank/126436919. Broccoli. jpg http: //www. butterball. com/en/images/plan_n_prep/preparing/carving 1. jpg THINK ABOUT IT What do oranges, broccoli and Butterball turkeys have to do with EVOLUTION? (Answers to come in this slide show!)

EVIDENCE OF EVOLUTION: selection 1. Artificial ________ Fossil record 2. ________ Geographic Distribution 3. ________ Anatomical homologies 4. ________ Embryology 5. ________ Molecular homologies 6. ________ see Natural selection happen 7. Can ________

ARTIFICIAL SELECTION WORKS Nature provides the variation through mutation and sexual reproduction and humans select those traits that they find useful EX: We have selected for and bred cows to produce more milk, turkeys with more breast meat, etc. http: //www. pp 3 moo. com/hm 2 cow. jpg http: //lazerbrody. typepad. com/photos/uncategorized/turkey. gif

WE’VE DONE IT WITH PLANTS BIOLOGY by Campbell and Reece Prentice Hall Publishing© 2005

WE’VE DONE IT WITH ANIMALS If humans can select for beneficial traits, why can’t nature? If artificial selection can achieve so much change in relatively short time, why can’t major changes happen over thousands of generations? http: //www. windows. ucar. edu/earth/geology/images/dogs_sm. jpg

http: //groups. wfu. edu/Model. UN/images/Cover/Oranges. jpg http: //www. fx. clemson. edu/~ablank/126436919. Broccoli. jpg http: //www. butterball. com/en/images/plan_n_prep/preparing/carving 1. jpg THINK ABOUT IT Now you know what broccoli and Butterball turkeys have to do with evolution! (Answers about oranges to come in this slide show!)

How Do We Know Evolution Happens? The Fossil Record provides evidence that organisms have changed over time. http: //www. bbc. co. uk/schools/gcsebitesize/img/bifossils. gif

If evolution has happened, we should be able to find evidence of evolution in the fossil record AND WE HAVE ! http: //en. wikipedia. org/wiki/Image: Tiktaalik_BW. jpg BBC Tiktaalik video http: //evolution. berkeley. edu/evosite/lines/IAtransitional. shtml

Lots of TRANSITIONAL FOSSILS have been found Scientific American; Dec 2005; Vol 293; p 100 -107

http: //evolution. berkeley. edu/evolibrary/images/news/tiktaalik_reconstruction. jpg TIK-TAALIK Intermediate between fish and early tetrapods • Fins have basic wrist bones and simple fingers • Earliest fish with a neck • Discovered by Neil Shubin and Ted Daeschler in 2004

GEOGRAPHIC DISTRIBUTION = BIOGEOGRAPHY If Darwin’s theory is correct you would expect to find closely related yet different species living in a geographic region as they spread into nearby habitats and evolve. That’s EXACTLY what we do see!

http: //images. encarta. msn. com/xrefmedia/aencmed/targets/illus/ilt/T 014608 A. gif GALAPAGOS FINCHES The beaks of Galapagos finches have adapted to eating a variety of foods

http: //www. newtonswindow. com/problem-solving. htm GALAPAGOS TORTOISES Intermediate vegetation Intermediate necks Little vegetation Long necks Image from: BIOLOGY by Miller and Levine; Prentice Hall Publisher© 2006 Lots of vegetation Short necks Tortoises adapted to different habitats as they spread from the mainland to the different islands. = DIVERGENT EVOLUTION = ADAPTIVE RADIATION

If Darwin’s theory is correct you would also expect to find different species living in far apart geographic regions but similar habitats becoming more alike as they adapt to similar environments. That’s EXACTLY what we do see!

BOTH LIVE IN FOREST ECOSYSTEMS Adapted to similar environments, but evolved independently from different ancestors. SUGAR GLIDER in Australia is a marsupial more closely related to Kangaroos than North American FLYING SQUIRRELS because its ancestors were marsupials.

http: //www. flmnh. ufl. edu/fish/gallery/descript/Tiger. Shark/scars. JPG http: //news. bbc. co. uk/2/shared/spl/hi/guides/456900/456973/html/nn 1 page 1. stm Whales and sharks have a similar body design even though they are very different organisms (one is a fish; the other, a mammal) because they have independently adapted to living in a similar environment. = CONVERGENT EVOLUTION

HOMOLOGOUS STRUCTURESForelimbs of all mammals share same arrangement of bones that can be traced to same embryological origin BIOLOGY by Campbell and Reece Prentice Hall Publishing© 2005

EVOLUTION explains why certain characteristics in related species have an Section 15 -3 underlying similarity. Turtle Alligator Ancient lobe-finned fish Bird Mammal

amnion /am·ni·on/ (am´ne-on) bag of waters; the extraembryonic membrane of birds, reptiles, and mammals, which lines the chorion and contains the fetus and the amniotic fluid http: //media-2. web. britannica. com/eb-media/27/117227 -050 -E 1 C 9 ABEE. jpg http: //medical-dictionary. thefreedictionary. com/amnions

VESTIGIAL ORGANS Some homologous structures are vestigial and have no useful function even though they are still present. Examples: Hipbones and pelvis in whales and boa constrictors Cecum (appendix) in humans Skink legs http: //www. txtwriter. com/backgrounders/Evolution/EVpage 12. html

Most mammals have a pouch between their small and large intestine that contains bacteria to digest plants called a cecum. In humans the cecum is shrunken and unused. It is our appendix http: //www. medicalgeo. com/images/appendix. gif

EMBRYOLOGY Development of vertebrate embryos follows same path Image from: http: //calspace. ucsd. edu/virtualmuseum/litu/03_3. shtml

Same groups of undifferentiated cells develop in the same order to produce the same tissues and organs of all vertebrates, suggesting that they all evolved from a common ancestor. Image from: http: //io. uwinnipeg. ca/~simmons/16 cm 05/1116/16 anim 3. htm

Why grow a tail and then lose it? HUMAN EMBRYO has a tail at 4 weeks which disappears at 8 weeks Pharyngeal pouches become gills in fish, parts of throat/ears in humans http: //www. suite 101. com/files/topics/6234/files/tail_Human. Tail. gif

Nonfunctional legs in skinks Why would an organism possess organs without function? Why would an organism grow a part and then discard it? If organisms evolved from ancestors in which that part functioned, the gene code to make the part would still be there even though it doesn’t work. If the organ is not vital to survival, then natural selection would not cause its elimination. http: //www. medicalgeo. com/images/appendix. gif

MOLECULAR HOMOLOGIES • All life forms share same genetic machinery (DNA & RNA) • Universal genetic code • Important genes share highly conserved sequences

Similarities in protein sequences suggests similarities in DNA Image from: Modern Biology by Holt, Rinehart, and Winston

MOLECULAR HOMOLOGIES Similarities in DNA and protein sequences suggest relatedness Image from: BIOLOGY AP EDITION by Campbell and Reece; Prentice Hall Publishing© 2005

Human- 46 chromosomes Chimpanzee- 48 chromosomes Similarities in karyotypes suggest an evolutionary relationship Human: http: //www. nationmaster. com/wikimir/images/upload. wikimedia. org/wikipedia/en/thumb/1/18/300 px-Human_karyogram. png Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

Human- 46 chromosomes Chimpanzee- 48 chromosomes Even differences show relatedness Chimpanzees have 2 smaller chromosome pairs we don’t have Humans have 1 larger chromosome pair (#2) they don’t have. Human: http: //www. nationmaster. com/wikimir/images/upload. wikimedia. org/wikipedia/en/thumb/1/18/300 px-Human_karyogram. png Chimpanzee: Middle School Life Science , published by Kendall/Hunt.

Remember: Protective TELOMERE sequences found at ends of chromosomes http: //joannenova. com. au/Speaking/Morslids. html

2. TELOMERES IN MIDDLE Human chromosome is only human chromosome that has telomere sequences at the ends BUT ALSO IN THE MIDDLE. . . suggesting it was made by joining two other chromosomes together. → → → http: //www. evolutionpages. com/chromosome_2. htm

EXTRA CENTROMERE _________ Chromosome #2 has a second inactive centromere region. . . suggesting it was made by joining two other chromosomes together. → Which chromosomes? http: //www. evolutionpages. com/chromosome_2. htm

BANDING PATTERN MATCHES ____________ If you take the two smaller chromosomes they have that we don’t, and place them end to end, the banding pattern is identical to human chromosome #2 http: //www. evolutionpages. com/chromosome_2. htm

Why don’t dogs and cats need to eat fresh fruit, but you do? http: //www. naturescornermagazine. com/Natures. Blog/images/dog%20 care%20 in%20 summer. jpg http: //www. alpo. com/where. aspx

Fish, amphibians, reptiles, and most mammals can make their own vitamin C, but humans can’t make vitamin C. Without fresh fruit, humans end up with scurvy. http: //www. med. uc. edu/departme/cellbiol/Image 7. gif http: //www. rachelleb. com/images/2005_02_22/scurvy. jpg

Human DNA contains the gene that codes for the enzyme to make vitamin C, but it is nonfunctional. Guess what other group of organisms lack the ability to make their own Vitamin C? PRIMATES… which includes chimpanzees, orangutans, gorillas, and other apes. http: //groups. wfu. edu/Model. UN/images/Cover/Oranges. jpg

PSEUDOGENES are vestigial genes. EX: Humans have more than 99 different odor receptor genes, but more than 70% of them are nonfunctional. http: //www. animationplayhouse. com/new/dogs 2. html http: //unraveling. typepad. com/photos/uncategorized/nose_1. jpg

Slide by Kim Foglia@ http: //www. explorebiology. com/

BIOLOGY by Campbell and Reece We can see Natural selection happen

BIOLOGY by Campbell and Reece We can see Natural selection happen

Can see Natural selection happen EX: Changes in disease-causing microbes that produce new organisms and new diseases. Bird flu _______ HIV ___ http: //www. hhmi. org/askascientist/images/hiv. gif Antibiotic-resistant tuberculosis _____________ Why does evolution matter now? http: //www. hipusa. com/e. Tools/webmd/A-Z_Encyclopedia/tuberculosis. jpg

Researchers have developed numerous drugs to combat HIV Percent of HIV resistant to 3 TC – But using these medications selects for viruses resistant to the drugs Patient No. 1 Patient No. 2 Patient No. 3 Weeks Graph from BIOLOGY by Campbell and Reece

PEPPERED MOTH Data from Kim Foglia @ www. biologyzone. com

Slide from Kim Foglia@www. biologyzone. com

Slide by Kim Foglia@www. biologyzone. com