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BIOL110s05-28 - BIOL 110 Principles of Biology Spring 2005...

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Unformatted text preview: BIOL 110: Principles of Biology Spring 2005 Lecture 28, F 4/8/05 http://www.smccd.net/accounts/staplesn/biol110/ • ONLINE Quizzes link: [Quiz #5 up today! Results of #4] – (Cañada College I.D. [G#] for login and password) (Cañ http://smcwebtest.smccd.net/accounts/staplesn/index.tpx http://smcwebtest.smccd.net/accounts/staplesn/index.tpx – Time-limited (so study well first!); ~ 30 minutes to complete Time- – Can view twice, submit once only. • Midterm 2 was Returned Friday. – Extra credit if scored <70%: Thoroughly rewrite answers to all missed questions; “Why the correct answer is right, why your answer was incorrect.” Due Mon. 4/11!! incorrect.” • Journal Reports #1 Were due Friday!! (-5% each day late!) • Next: Ch. 12, bits of 13, 14….. REVIEW: • Ch. 11: Studying and Manipulating Genomes – Recombinant DNA technology • Cutting and Splicing; DNA carriers (“VECTORS”) (“ VECTORS” • Amplifying DNA – bacteria as host; or in test tube (PCR) TODAY: • Ch. 12: Processes of Evolution – Artificial selection; evidence for evolution – old & new theories; Darwin’s voyage Darwin’ 1 Rise of the Super Rats • Warfarin is a chemical pesticide used against rodents • When introduced the the 1950s it was extremely effective • Over time, the proportion of warfarin-resistant rats has risen in warfarinplaces where the chemical is used – “Microevolution” Microevolution” – Small but persistent changes in a species population over time. I. Selective Breeding & Evolution • Evolution is genetic change in a line of descent through successive generations • Selective breeding practices yield evidence that heritable changes do occur 2 Domestication of Dogs • Began about 50,000 years ago • 14,000 years ago - artificial selection – Dogs with desired forms of traits were bred • Modern breeds are the result Results of Artificial Selection Results • Extremes in size – Great Dane and Chihuahua • Extremes in form – Short-legged dachshunds – English bulldog • Short snout and compressed face • Extreme traits lead to health problems 3 II. Evolutionary Theories • Widely used to interpret the past and present, and even to predict the future • Reveal connections between the geological record, fossil record, and organismal diversity Early Scientific Theories: Observations by great thinkers! • Hippocrates - All aspects of nature can be traced to their underlying causes • Aristotle - Each organism is distinct from all the rest and nature is a continuum or organization 4 Confounding Evidence 1. Biogeography 2. Comparative anatomy 3. Geologic discoveries A. Biogeography • Size of the known world expanded enormously in the 15th century – exploration! • Discovery of new organisms in previously unknown places could not be explained by accepted beliefs – How did species get from center of creation to all these places? Figure 12.1a-c Page 179 Rhea South America Emu Australia Ostrich Africa 5 Figure 12.1d,e Page 179 Cactus North America Spurge Africa B. Comparative Morphology • Study of similarities and differences in body plans of major groups. • Puzzling patterns: – Animals as different as whales and bats have similar bones in forelimbs – Some parts seem to have no function • “Vestigial Organs” – useless leftovers from Organs” evolutionary ancestors. 6 Comparative Anatomy Python Human Vestigial pelvic girdle and hind limbs! ** Not all adaptations are perfect and unchangeable! Evolution!! Evolution!! Basilosaurus Figure 12.2 Page 180 Ankle bone Ankle bone 7 Morphological Divergence • Change from body form of a common ancestor • Produces homologous structures 3 4 2 5 4 2 3 4 3 21 5 21 3 early reptile pterosaur 1 chicken 1 2 bat 34 1 5 2 3 4 5 porpoise penguin 2 1 3 human D. Geological Discoveries • Similar rock layers throughout world • Certain layers contain fossils fossils • Deeper layers contain simpler fossils than shallow layers • Some fossils seem to be related to known species 8 II. 19th Century - New Theories • Scientists attempt to reconcile evidence of change with traditional belief in a single creation event • Two examples: – Georges Cuvier - multiple catastrophes • Successive cycles of great catastrophes, and survivors dominate next generations – Jean Lamark - inheritance of acquired characteristics • Oranisms undergo physical changes to adapt to their immediate environment pass changes on to next generations pass • Giraffe example.. The Theory of Uniformity (read by Darwin on the Beagle) Beagle • Charles Lyell’s Principles of Geology • Subtle, repetitive processes of change, had shaped Earth – Some catastrophes do happen, but no more significant than gradual change • Challenged the view that Earth was only 6,000 years old – Millions of years = time for gradual evolution!! 9 III. Darwin’s Voyage • At age 22 (1831-36), Charles Darwin began a 5-year, round-the-world voyage aboard the Beagle Beagle • In his role as ship’s naturalist naturalist – collected and examined the species that inhabited the regions the ship visited Volcanic islands far off coast of Ecuador EQUATOR Galapagos Islands All inhabitants are descended from species that arrived on islands from elsewhere A. Glyptodonts & Armadillos • In Argentina, Darwin observed fossils of extinct glyptodonts • Animals resembled living armadillos Pleistocene glyptodont Armadillo 10 B. Malthus - Struggle to Survive • Thomas Malthus, a clergyman and economist, wrote essay that Darwin read on his return to England • Argued that as population size increases, resources dwindle, the struggle to live struggle intensifies and conflict increases C. Galapagos Finches • Darwin observed finches with a variety of lifestyles and body forms • On his return he learned that there were 13 species 13 • He attempted to correlate variations in their traits with environmental challenges 11 Darwin’s Theory • A population can change over time …. population • When individuals differ in one or more differ heritable traits …. • That are responsible for differences in the differences ability to survive and reproduce. – Populations evolve, NOT individuals!! On the Origin of Species • Darwin’s book -- prompted by co-discoverer, Alfred Wallace • Published in 1859 – (23 years after voyage of the Beagle!!) • Laid out in great detail his evidence in support of the theory of evolution by theory natural selection natural 12 ...
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