E V O L U T I O

E V O L U T I O N Regents Biology

OBJECTIVES Upon completion of this unit students will be able to: 1. Describe 5 processes by which fossils may be formed. 2. Explain why fossils are often found in sedimentary rocks. 3. Differentiate relative and absolute dating. 4. Explain how radioactive dating can determine the age of rocks. 5. Define the terms correlation and index fossil. 6. Explain what is meant by the geologic time scale. 7. State two important conclusions that can be drawn from the fossil record regarding the course of changes in living things over geologic time. 8. Explain the importance of extinctions. 9. Differentiate analogous, homologous, and vestigial structures. 10. Explain how similarities in biochemistry, anatomy, and embryonic development show an evolutionary relationship between different species. 11. Describe spontaneous generation. 12. Explain how Redi initially disproved spontaneous generation. 13. Explain how Spallanzani’s and Pasteur’s experiments finally disproved spontaneous generation. 14. Describe the conditions thought to have existed on the primitive earth according to the heterotroph hypothesis, and experiments supporting it. 15. Outline Lamarck’s theory of evolution and describe how Weismann’s experiment disproved it. 16. Explain the principle of natural selection and give examples 17. List the six main points of Darwin’s theory of evolution and state the weaknesses to his theory. 18. Differentiate gradualism and punctuated equilibrium. 19. List the causes of genetic variation in a species. 20. Explain what an adaptation is and give examples. 21. Describe different types of speciation.

KEY WORDS 1. adaptation 2. correlation 3. fossil 4. fossil record 5. gene pool 6. geologic evolution 7. gradualism 8. index fossil 9. natural selection 10. organic evolution 11. population genetics 12. punctuated equilibrium 13. speciation 14. taxonomy

EVIDENCE OF EVOLUTION • Evolution: GRADUAL CHANGE FROM ONE STATE TO ANOTHER • Geologic evolution: CONTINUAL CHANGE OF THE EARTH (4. 5 BYA) • Organic evolution: CONTINUAL CHANGE OF LIVING THINGS

I. FOSSILS • Fossil: REMAINS/TRACE OF AN ORGANISM; STRONGEST EVIDENCE OF ORGANIC EVOLUTION • Types of fossil formation: 1. Preservation in amber – TRAPPED/EMBEDDED IN RESIN 2. Preservation in ice – FROZEN REMAINS 3. Preserved hard parts - BONES 4. Petrifaction – REMAINS TURN TO STONE 5. Molds and Casts - MOLD = SHAPE PRESERVED (HOLLOW); CAST = MOLD FILLS WITH MINERALS (SOLID) 6. Imprints – IMPRESSION THAT HARDENS

http: //images. google. com/imgres? imgurl=http: //www. abc. net. au/beasts/evidence/prog 1/images/evi _fossil 1_large. jpg&imgrefurl=http: //www. abc. net. au/beasts/evidence/prog 1/page 1. htm&h=315&w= 400&sz=19&hl=en&start=8&tbnid=pqg. QLZ 5 Ng. Vuok. M: &tbnh=98&tbnw=124&prev=/images%3 Fq% 3 DFOSSIL%26 gbv%3 D 2%26 hl%3 Den%26 client%3 Dfirefox-a%26 rls%3 Dorg. mozilla: en. US: official%26 sa%3 DG http: //images. google. com/imgres? imgurl =http: //news. nationalgeographic. com/news/2007/08/images/070816 -fossil-spider_big. jpg&imgrefurl=http: //news. nationalgeographic. com/news/2007/08/070816 -fossilspider. html&h=439&w=461&sz=61&hl= en&start=6&tbnid=v. P 3 d. G-j. Nw_NL 2 M: &tbnh=122&tbnw=128&prev=/images%3 Fq%3 DFOSSIL%26 gbv%3 D 2%26 hl%3 Den%26 client%3 Dfirefox-a%26 rls%3 Dorg. mozilla: en-US: official%26 sa%3 DG

II. SEDIMENTARY ROCKS • The YOUNGEST layer is always found at the TOP: http: //stloe. most. go. th/html/lo_index/LOcanada 2/206/images/2_6_1 en. jpg http: //www. moorlandschool. co. uk/earth_science/utah_sandstone. jpg • Layers of sedimentary rock that contain FOSSILS tell us about what existed at a particular PLACE and TIME

III. THE FOSSIL RECORD: HISTORY OF LIFE A) Relative Dating – DETERMINING THE ORDER OF EVENTS http: //facweb. bhc. edu/academics/science/harwoodr/Geol 101/labs/Dating 2/Images/relative 02. gif

B) Correlation – MATCHING LAYERS TO DO RELATIVE DATING (MATCHING AGES OF ROCK THAT ARE CLOSE IN PROXIMITY) http: //stloe. most. go. th/html/lo_index/LOcanada 8/802/images/eng/1_2. jpg

C) Index fossils – RELATIVE DATING OF ROCKS WITHIN A NARROW TIME FRAME; MATCHING RELATIVE AGES OF SEDIMENTARY ROCK AT VERY DIFFERENT PLACES) http: //www. adrian. edu/chemistry/th/Somelinks/Spages/ttackett/fossils. gif

D) Characteristics of the Fossil Record 1. The earliest organisms were relatively SIMPLE 2. There is a GRADUAL transition from EARLIER forms to LATER forms Later forms developed from early forms by a series of changes passed on from generation to generation; there are “missing links” (a. k. a. TRANSITIONAL FORMS)

IV. ABSOLUTE DATING • Tells us the ACTUAL age of something • RADIOACTIVE DATING is the most accurate and reliable method (igneous rocks only) http: //evolution. berkeley. edu/evosite/lines/images/strat_column. gif

V. GEOLOGIC TIME SCALE • Time table of the earth’s history • Each ERA is divided into PERIODS (epochs)

VI. OTHER EVIDENCE OF EVOLUTION A) Comparative Anatomy – STUDY OF STRUCTURAL SIMILARITIES AND DIFFERENCES AMONG LIVING THINGS • Similar anatomies provide evidence about EVOLUTIONARY RELATIONSHIPS between organisms Http: // www. talkorigins. org/faqs/homs/pelvi s. jpg • Homologous structures are parts on DIFFERENT organisms that have similar STRUCTURE but different FUNCTION; this shows evolution along the SAME LINES EXAMPLES: hand of a human, flipper of a whale, front leg of cat, wing of bat, wing of bird

HOMOLOGOUS STRUCTURES (SIMILAR STRUCTURE, DIFFERENT FUNCTION)

• Analogous structures are parts on DIFFERENT organisms that have different STRUCTURE but similar FUNCTION ; this shows evidence of evolution along DIFFERENT LINES EXAMPLES: wing of a bird, wing of an insect http: //www. bio. miami. edu/dana/pix/analogous. gif

• Vestigial structures are the remnants of structures that were once FUNCTIONAL in our ancestors, but now are SMALLER and serve little or no function EXAMPLES: human coccyx, appendix, wisdom teeth, muscles that move the nose and ears http: //content. answers. com/main/content/wp/en/thumb/f/f 0/250 px-Eye_0012. jpg http: //images. google. com/imgres? imgurl=http: //content. answers. com/main/conte nt/wp/en/5/5 f/Chickenblinking. jpg&imgrefurl= http: //www. answers. com/topic/nictit atingmembrane&h=199&w=252&sz=42&hl=en&start=16&tbnid=x. Fy. FBUQLqcmtm. M: &tbnh=88&tbnw=111&prev=/images%3 Fq%3 Dnictitating%2 Bmembrane%2 Bhu man%26 gbv%3 D 2%26 ndsp%3 D 20%26 hl%3 Den%26 client%3 Dfirefoxa%26 rls%3 Dorg. mozilla: en-US: official%26 sa%3 DN

B) Comparative Embryology • Similarities in embryonic development supports the idea that CERTAIN ORGANISMS HAVE A COMMON EVOLUTIONARY ORIGIN • The more two organisms resemble each other as adults, the MORE CLOSELY RELATED THEY ARE (EXAMPLE: humans and chimps) http: //www. terradaily. com/images/human-chimp-anatomy-comparison-bg. jpg

C) Comparative Biochemistry and Immunology • The closer the evolutionary relationship between two organisms, the more alike their structure of THEIR DNA and PROTEIN MOLECULES EXAMPLE: the hemoglobin of humans and gorillas is the same except for one amino acid! http: //www. bloodless. it/hemoglobin. jpg

VII. THEORIES OF EVOLUTION A) Lamarck o Was a scientist who believed that evolutionary changes were caused by the need to ADAPT TO THE ENVIRONMENT o He came up with two principles: 1. The Law of Use and Disuse • The more something is used, the STRONGER its development • The less something is used, the WEAKER its development 2. Inheritance of Acquired Characteristics • Characteristics of an organism developed through USE AND DISUSE could be passed on to OFFSPRING EXAMPLE: neck of a giraffe (see figure on next page)

B) Weismann Disproved Lamarck’s theory Hypothesized that traits are passed on to offspring by GENES, not life experiences He cut the tails off of mice for 22 generations; all of the new mice had normal tails; therefore tail length is not INHERITED http: //www. bbc. co. uk/manchester/content/images/2005/09/01/rebecca_mcevoy_mouse_tail_203 x 152. jpg

C) Charles Darwin observed many species during his travels, namely at the GALAPAGOS ISLANDS Some observations he made while traveling: 1. There seemed to be a GRADUAL change in species as he moved down the coast of SOUTH AMERICA 2. Fossils that he found were unlike anything he had seen; were they related to modern forms? http: //www. ecuador. us/images/mapgalap. gif

3. The finches (type of bird) on the Galapagos Islands appeared different due to ISOLATION AND ADAPTATION

D) Darwin’s Theory of Evolution • Darwin’s theory was composed of several ideas: 1. Overproduction: SPECIES POPULATIONS REMAIN CONSTANT; ALL OFFSPRING DOES NOT REPRODUCE 2. Struggle for Existence: SPACE AND FOOD ARE LIMITED, SO THERE IS COMPETITION 3. Variation: DIFFERENCES BETWEEN INDIVIDUALS (SOME MORE IMPORTANT THAN OTHERS) 4. Survival of the Fittest: SOME INDIVIDUALS ARE BETTER EQUIPPED THAN OTHERS TO SURVIVE AND REPRODUCE (ADAPT BETTER TO THE ENVIRONMENT) 5. Natural Selection: ORGANISMS WITH FAVORABLE VARIATIONS ARE ABLE TO SURVIVE AND REPRODUCE BETTER THAN ORGANISMS WITH UNFAVORABLE CHARACTERISTICS; CAN RESULT IN NEW SPECIES 6. Evolution of New Species: OVER TIME, THE FAVORABLE CHANGES BECOME SO GREAT THE NET RESULT IS A NEW SPECIES

http: //www. globalchange. umich. edu/globalchange 1/current/lectures/selection/boxes. gif

• WEAKNESSES to Darwin’s theory: 1. Does not explain the ORIGIN and transmissions of VARIATIONS 2. Variations caused by HEREDITARY DIFFERENCES vs. those caused by THE ENVIRONMENT (NOT INHERITED)

E) Rate of Evolution • The rate of evolution, or HOW FAST/SLOW IT OCCURS, is not agreed upon. There are two “camps” within the scientific community (Gradualism vs. Punctuated Equilibrium): GRADUALISM PUNCTUATED EQUILIBRIUM · DARWIN · GOULD & ELDEREDGE · EVOLUTION OCCURS SLOWLY AND GRADUALLY · PERIODS OF EQUILIBRIUM ARE INTERRUPTED BY A SHORT PERIOD OF RAPID EVOLUTION

F) Synthetic Theory of Evolution • Scientists that back this theory believe that evolution happens to POPULATIONS, not INDIVIDUALS • INDIVIDUALS are the units of natural selection • Evolution is a change in ALLELE FREQUENCY within a population over a period of time

VIII. DEVRIES AND THE MUTATION THEORY • Devries added MUTATION to Darwin’s theory • He claimed that changes leading to new species occurred in SUDDEN, LARGE changes in heredity resulting from MUTATION, NOT slowly over time EXAMPLE: the giraffe with the long neck was from a mutation; the environment changed and the long neck was advantageous, and this species survived

IX. SOURCES OF VARIATION A) Gene mutations • Gene mutation are the MAJOR source of variation • Mutations of particular genes are RARE, but among thousands, at least ONE gene is mutated • Most gene mutations are RECESSIVE (PKU, white-eyed fly, etc. ) B) Chromosomal mutations • Does not produce new GENES, but results in new COMBINATIONS of genes in the organism (Down Syndrome, etc. ). C) Recombination • New combinations of alleles from: 1. MEIOSIS (crossing-over, independent assortment) 2. FERTILIZATION D) Immigration and Emigration • Immigration: INDIVIDUALS MOVING INTO A POPULATION, BRINGING GENES NOT ALREADY PRESENT • Emigration: INDIVIDUALS LEAVING A POPULATION,

X. POPULATION GENETICS • Population: ORGANISMS OF THE SAME SPECIES LIVING TOGETHER AND ARE CAPABLE OF INTERBREEDING • The genetic makeup of a population changes from GENERATION to GENERATION (it evolves) • As individuals reproduce and die, the GENETIC MAKEUP of a population changes XI. ALLELE FREQUENCIES • Each individual of a population has a set of ALLELES that is not the same as any other individual, although individuals do have many of the same ALLELES • Total alleles in a population is known as the. GENE POOL • Each allele occurs in the gene pool with a certain FREQUENCY (100% 0%) • As time goes on, the allele frequency in the gene pool may change as a result of NATURAL SELECTION • Evolution: GRADUAL CHANGE OF ALLELE FREQUENCY IN A POPULATION

XII. DIFFERENTIAL REPRODUCTION • MUTATIONS NEW ALLELES VARIATION • Individuals with favorable variations will survive LONGER (natural selection) Certain allele frequencies will increase (FAVORABLE) and others will decrease (UNFAVORABLE) EXAMPLE: In the original giraffe population, the alleles for the long neck were at a LOW frequency; the change in the environment caused the alleles for the long neck to be at a HIGH frequency (eventually 100% frequency)

XIII. THE HARDY WEINBERG-LAW • EXAMPLE: allele for white eye = 90% frequency; allele for red eye = 10% frequency Question: What will happen to these frequencies as time goes on? Will white eyes replace red eyes so that white eyes = 100% frequency? If all of these happen, there will be no change in allele frequency Answer: NO !!!! Sexual reproduction alone cannot change allele frequency (this is known as the HARDY-WEINBERG LAW) • Requirements for the Hardy-Weinberg Law: 1. LARGE POPULATION 2. NO MIGRATION 3. NO MUTATIONS 4. RANDOM REPRODIUCTION • What’s the point? To show that EVOLUTION IS OCCURING and that the ALLELE FREQUENCIES ARE CHANGING

XIV. ADAPTATIONS • Adaptation: INHERITED TRAIT THAT IMPROVES AN ORGANISMS’ CHANCE OF SURVIVAL AND REPRODUCTION • Adaptations can be STRUCTURAL or PHYSIOLOGICAL EXAMPLES: camouflage (blending), warning coloration (easier to see), mimicry (resembling something else) http: //3 quarksdaily. blogs. com/3 quarksdaily/images/wolfe_seal_1. jpg http: //xnet. rrc. mb. ca/davidb/laselva 62_jpg_jpg. jpg

XV. SPECIATION A) Geography • Range : EACH SPECIES FOUND IN A REGION • Characteristics of species are often different in different parts of its RANGE • Sometimes when species are separated, they cannot INTERBREED and a new species develops http: //bio. research. ucsc. edu/~barrylab/classes/animal_behavior/IMAGES 4. DIR/SPECMODE. GIF

B) Types of Speciation 1. ISOLATION – NO INTERBREEDING WITHIN A SPECIES • Geographic isolation – NATURAL BARRIERS (ISLANDS, MOUNTAINS, ETC. ) • Reproductive isolation – MATING BARRIERS (COURTSHIP BEHAVIOR, MATING TIMES) 2. POLYPLOIDY – 3 n, 4 n, 5 n # OF CHROMOSOMES • These offspring can interbreed only among THEMSELVES 3. ADAPTIVE RADIATION – ANCESTOR EVOLVES INTO SEVERAL DIFFERENT SPECIES, EACH IN A DIFFERENT HABITAT (DARWIN’S FINCHES) 4. CONVERGENT EVOLUTION – UNRELATED SPECIES RESEMBLE EACH OTHER DUE TO NATURAL SELECTION (SIMILAR ADAPTATIONS) EXAMPLE: marsupial mouse – rodent Tasmanian wolf – wolf Koala bear – bear All have similar needs in similar environments

Speciation by Isolation http: //www. pandasthumb. org/pt-archives/allopatry. jpg Speciation by Adaptive Radiation http: //images. google. com/imgres? imgurl=http: //www. pbs. org/wgbh/evolution/library/01/6/images/l_016_02_l. gif&imgrefurl=http: //www. pbs. org/wgbh/evolution/library/01/6/image_pop/l_016_02. html&h=284&w=500&sz=30&hl=en&start=10&sig 2=CWbxl 3 By. Jaztcd. FZt 5 ZYr. A&tbnid=0 o 6 Vft. Bv. CEqr. M: &tbnh=74&tbnw=130&ei=ZVU 9 SK 6 RHo. SYeo. HC 8 LIO&prev=/images%3 Fq%3 Ddarwin%2527 s%2 Bfinches%26 gbv%3 D 2%26 hl%3 Den%26 client%3 Dfirefox-a%26 rls%3 Dorg. mozilla: en-US: official%26 sa%3 DG Speciation by Polyploidy http: //polyploid. agronomy. wisc. edu/overview/Slide 2. gif Speciation by Convergent Evolution http: //www. freewebs. com/carakiller/convergent%20 evolution. jpg

A) BACTERIAL RESISITANCE TO ANTIBIOTICS • Antibiotics kill BACTERIA • Resistant strains of bacteria appeared due to FREQUENT USE • Antibiotics are no longer effective in killing certain strains: • In large populations of bacteria, some individuals have what is called RESISTANCE to an antibiotic (resistance is a genetic trait) • In an environment containing the ANTIBIOTIC, only the resistant STRAINS will grow and reproduce • By NATURAL SELECTION, the strain with resistance becomes the common type A pure culture of bacteria can be tested for antibiotic resistance by evenly swabbing it over an agar plate and pressing discs of antibiotic into the agar. After a period of incubation, sensitivity or resistance to the antibiotic can be determined by measuring the zone that forms around the disc. Large zones mean the bacteria are sensitive to the drug, small or nonexistent zones are signs of resistance. Image Courtesy: Centers for Disease Control and Prevention. http: //images. google. com/imgres? imgurl =http: //www. jyi. org/articleimages/555/originals/img 0. jpg&imgrefurl=http: //www. jyi. org/news/nb. php%3 Fid%3 D 555&h=291&w=433&sz=20&hl= en&start=5&sig 2=MFLMVTtac 5 VUHc. WYevo 5 Wg&um=1&tbnid=fa. Rxq. UHFSJZ 0 M: &tbnh=85&tbnw=126&ei=f. X 49 SN-YGabaeo. GDj. Kw. O&prev=/images%3 Fq%3 Dantibiotic%2 Bresistant%2 Bbacteria%26 um%3 D 1%26 hl%3 Den%26 client%3 Dfirefox-a%26 channel%3 Ds%26 rls%3 Dorg. mozilla: en-US: official%26 sa%3 DN

http: //biopsy. files. wordpress. com/2008/04/antibiotic-resistance. jpg

B) INSECT RESISITANCE TO DDT • DDT kills insects • Some insects have a natural RESISTANCE to DDT • DDT-sensitive insects get KILLED when exposed to DDT • DDT-resistant insects SURVIVE and multiply by NATURAL SELECTION • Eventually, many insects will be RESISTANT to DDT Diamondback moth resistance to insecticide in Georgia http: //pubs. caes. uga. edu/caespubs/pubcd/C 899 -graphics/C 899 -cover. jpg

XVII. EARLY BELIEFS ABOUT THE ORIGIN OF LIFE A) EARLY OBSERVATIONS • Many believed that living organisms could arise spontaneously from nonliving matter, this is called SPONTANEOUS GENERATION http: //www. crystalinks. com/egyptplant. gif

B) Redi and maggots • Redi disproved the idea of SPONTANEOUS GENERATION • Common observation: when meat is exposed to the air, MAGGOTS appear • Many people thought that the maggots were formed from the meat; but this is WRONG! • Redi concluded that maggots did not arise spontaneously from decaying meat, but from EGGS LAID BY FLIES

C) Boiled Soup 1. Needham – reinforced belief in SPONTANEOUS GENERATION o Boiled broth to kill MICROORGANISMS o Microorganisms didn’t DIE 2. Spallanzani – disproved Needham o “Hey---Paisan---you didn’t heat the broth long to enough to KILL THE BACTERIA!!!”

3. Pasteur – Finalized that there is no SPONTANEOUS GENERATION o Microorganisms and their spores are present in the AIR o They become active and reproduce in the BROTH

XVIII. MODERN THEORY ON THE ORIGIN OF LIFE The Heterotroph Hypothesis (A. I. Oparin) • The heterotroph hypothesis assumes that the world was once different: THEN · HYDROGEN, WATER, AMMONIA, METHANE IN ATOMOSPHERE · TEMPERATURE RELATIVELY HIGH · OCEANS HOT NOW · NITROGEN, OXYGEN, CARBON DIOXIDE IN ATMOSPHERE · TEMPERATURE “NORMAL” · OCEANS NOT HOT • The primitive atmosphere promoted chemical reactions, which led to the synthesis of ORGANIC COMPOUNDS (radiation, electric energy, X-rays, etc. all give off energy!) • Miller later demonstrated that this could happen in a lab:

http: //www. kennislink. nl/upload/150080_962_1144771463083 -oersoepexperiment. Miller. jpg

COACERVATES (clusters of protein) Absorbing material from environment (heterotrophs) COACERVATES GROW & REPRODUCE Supply of materials decreased COMPETITION AMONG HETEROTROPHS Favorable adaptations survived PHOTOSYNTHETIC ORGANISMS (USE LIGHT FOR ATP)

Give off oxygen MORE OXYGEN IN THE AIR Aerobic respiration favored AEROBIC ORGANISMS DOMINANT • The earth’s environment was completely altered (old conditions were DESTROYED)