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This 12 page Class Notes was uploaded by Elise Bratton on Wednesday September 28, 2016. The Class Notes belongs to biol 120-005 lec at Towson University taught by Richard A. Seigel in Fall 2016. Since its upload, it has received 7 views.
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Date Created: 09/28/16
Scientists & Non-scientists: A failure to communicate Gap in understanding Theories doubted or rejected by public Ex. Autism and vaccines Why? Lack of understanding how scientists really work & how they are Major difference is intensity of curiosity about world rather than intellectual ability Scientific Method: One of the most misunderstood concepts Actually trained & organized common sense Set of guidelines or a philosophy to make sense of complicated world Sense & nonsense (acknowledge difference) A “rational skeptic,” a person opens to all ideas & ways of thinking about things yet wants to evaluate the evidence first Critical evaluations Video notes: Hair Commercial—example of why you should be a rational skeptic No background info Nothing to support claims Clinically proven? Unknown origins More examples of why one should be a rational skeptic… Vitamins Autism & vaccines Video notes: Vaccines & Autism The vaccine autism controversy Epidemic of false belief Fraudulent study linking autism to vaccines 1998 study by Andrew Wakefield with 12 children Altered clinical data Herd Immunity: Group of individuals No immunizations vs. with immunization Immunized individuals shield diseases from spreading (i.e. through herd immunity) More parents are believing vaccines are “unnecessary,” this leads to outbreaks of diseases Key Steps in Studying biology: 1. Observations/Questions Question based on natural occurrence that sparks natural curiosity The more specific the question the better Small steps 2. Hypothesis Tentative yet testable explanations for experiment Science works by testing & falsifying hypothesis - No test, no science 3. Test hypothesis Via field or in lab 4. Publication Communication throughout scientific groups Repetition & refinement of work Not done easily; rejection rate of 80% or more (often calls for extension of work) - Publication examples on BB & TU library 5. Theory Once a hypothesis was repeatedly being found true, it will become a theory View that public has of theory-- Tentative & poorly supported idea Difference between fact & theory is that a theory is still falsifiable Ex. Evolution Misconceptions about science & religion Science is not opposed to religion Testability is key component Science has no standing with supreme being because it cannot be tested Scientists are not anti-religious Science can be subverted: Finding the truth Subverted how? 1. Pressure from government 2. Pressure from industry 3. Scientific fraud Pressure from Government US government supports scientific research Scientific freedom Modifying & facilitating the release of data Video Clip: Polar Bears Lack of sea ice Causing fasting, can’t hunt 2/3 of population could disappear by 2020 Endangered species Video clip: James Mansen Non-politics science Research about climate change (harmful effects) Interaction between humans & climate Rewritten report by NASA regarding humans effect on environment Greenhouse effect—increase of Co2—heating of earth There is a lack of efficient energy Pressure from Industry Biochemical science- drugs for diseases (very expensive; sometimes tens of millions of dollars” Financially supported by pharmaceutical industry New drugs tested by pharmaceutical & academic scientists for independent results Non-disclosure agreement- used to protect intellectual property (details of research) Ethical dilemma—caused when non-disclosure agreement is abused Video Clip: Nancy Oliveri court case—Oliveri discovered a lethal drug & went public with her research broke non- disclosure agreement scrutinized & persecuted but despite pressure she was successful with her choice of morality won 1999 ethics & honors award Vindicated for her courage Fraud Outright fraud- scientists falsify data to get particular conclusion Seen mostly in biochemical studies (ex. Vaccines & autism) Turtles: Conservative specialists Members of the class reptilian (snakes, lizards, crocs) 3 smallest group of reptiles Seen as conservative survivors, they have existed largely unchanged for 2004 million years Character of group is pretty simple, the presence of girdles and a rib cage joining together and being covered by a shell protects the animal from predators Managed to adapt to living everywhere Ex. tortoise—land Sea turtles—sea/ ocean Most turtles—freshwater Types of Turtles & the cause of their endangerment: Gopher tortoise (terrestrial)- note high domed shell, thick legs no webbing Softshell turtle (aquatic)- note loss of hard shell, streamlines, thick legs, no webbing Wood turtle (semi-aquatic)- note found in MD, lives in streams, woodlands Alligator snapping turtle- largest freshwater turtle Leatherback sea turtle- largest species of turtle Main threats to turtles: - Habitat loss (all species) - Emerging diseases - Collected for meat & trade - Commercial collecting especially bad, since turtle populations depend on long adult lifespans (99% of eggs are taken by predators) - Normally adults 40-200 years, allowing chance to replace themselves before death. But not if adults are collected for meat, pets, & shells - Commercial collecting is still common, even in MD Upper respiratory tract disease- drippy nostrils, appearance of very unhealthy looking turtles, eventually leads to suffocation Ranavirus- a new threat that affects reptiles and amphibians (similar to URTD) Turtle planking- killing of turtles for sport Becoming a “rational skeptic” Whenever you hear about a new discovery via idea, paper, media consider: What was the question/hypothesis that was being tested? - Is it apparent? - Quality of work? - Design of study effective? Are you convinced there are no obvious biases with the study method? - Who’s involved? Ex. 4/5 doctors; investigate specifics Is there enough data to make a solid conclusion? - Is it safe? - Is it overall effective? Ex. pharmaceutical companies taking advantage of publics lack of scientific knowledge Has the data been published & replicated? - If so, in what? - Has this been verified by other credible scientists? Is the study tainted? - Is there guaranteed validity? The Origin of the Universe Starts with “big bang,” but the more accurate term is “big balloon” Before BB all energy & matter was compressed which began massive expansion about 13.5 BYA The cause of this phenomena is still a mystery Universe is cyclical—entropy (state of disorganization) increase, expansion of universe slows down When the expansion stops the universe will collapse on itself. (the matter will be compressed into a small area) then it reaches a “critical mass” & begins to re- expand Video Notes: Ted Talk Huge clouds of hydrogen & helium WMap satellite Gravity more powerful Compacted clouds – increased heat Stars formed When large stars die, heat increases & creates protons The Origin of the Sun Next major step to life on earth is the origin of the sun (sol) Hypothesis suggests that sun is formed from accumulation of dust, hydrogen & helium gas whirling through space Cloud condensed as gravity pulled particles closer together, in a process known as accretion Cloud gets denser atoms begin to collide heat is released increasing the rate of collision nuclei of atoms fuse creates nuclear fusion reaction (giant hydrogen bomb) Stars explode & form nova/supernovas Lightyear- distance light travels in one year The ongoing thermonuclear reaction is the basis for life on earth; originated about 5 BYA Our 3 generation stars formed from matter leftover from 1st & 2 nd generation stars exploded as novas and supernovas, this sends complex elements into outer space to turn into stars and planets themselves This is how complex elements & compounds are formed Origin of the Planets Planets formed from gas and dust moving around the newly formed star They were similar in nature than that which formed the sun Never achieved enough energy for fusion to occur Earth began to form about 4.6 BYA As earth & other planets were forming, temperatures were extremely high; creating a molten interior (volcanoes) We still see the basic structure in earth today, hot interior surrounded by thin cool layer of solid matter Such high temperatures released gases from the interior Materials that composed atmosphere of early earth (nitrogen, hydrogen, helium, methane, oxygen, & water vapor) As surface cools, an outer crust of hard material began to form, as thick as skin of apple Oldest known rock 3.98 BYA Origin of life Widely studied hypothesis for origin of life Each has pro’s & cons 1. Organic soup hypothesis (Oparin, Miller, Urey) 2. Deep sea hypothesis 3. Panspermia (extraterrestrial) Conditions for development of life - Oldest fossils about 3.5 BYA - Need for free standing water & cooler temperatures - All of raw materials necessary for survival were there - Earth hot water vapor rises into atmosphere earth cools vapor falls to hot surface as rain evaporates falls as rain - Known as “World longest thunderstorm,” lasting millions of years until the crust began to cool - Earth’s surface cools rain no longer evaporates large pools of water form, shallow and deep 1.) Organic Soup hypothesis How does this lead the origin of life? - 1922, Russian scientist Aleksander Oparian suggested given sources of energy, basic chemical compounds rise complex materials like sugar, fats, & protein - Inorganic compounds + energy = organic compounds - Organic compounds + energy = life - Energy from heat, UV lights (sun), electrical energy (thunderstorms) - Conditions simulated theory in lab by Miller & Urey - They put a mixture of methane, ammonia, hydrogen & water into a closed system & high heat + electricity for a week - After a week, the clear water turned into a thick, brown soup - When tested, the soup contained a mixture of organic chemicals, especially amino acids (building blocks of protein) - Materials in primitive atmosphere would dissolve in rain & collect in the shallow warm seas that were forming at this time, creating a rich organic soup - Organic materials spontaneously aggregate, and would even become enclosed in thin membranes of protein & fat, precursor to membrane of today’s cells - Come under modification: a. Did oxygen exist in early earth? b. Could raw materials have come from meteor strikes? c. Could those meteors have vaporized life just as it got going? 2. Deep Sea hypothesis Deep sea vents (volcanic, hydrothermal) Constant source of heat & nutrients Has advantage of: a. Protection from asteroid strikes b. Constant source of energy c. Direct evidence from today Chemosynthesis- existence of life w/o energy from the sun 3. Panspermia Raw materials from life came from outer space Meteors carried forms of life on them which contain organic materials (supported) Final Questions: 1. Why Earth? Distance from sun (perfect temperature) Size 2. Life only on Earth? Time Frame - Understanding the vast amount of time that has passed since earth was formed to present day - Reflect by looking at biological time clock 3. Why study genetics? It’s difficult but essential for living in 21rst century Aspects in modern life are controlled by genetics - GMO’s - Susceptibility - Children Mendel Genetics Gregor Mendel- Monk who lived in Austria, referred to as “father of modern genetics” Conducted groundbreaking experimental studies, which lead to the discovery of genetic information They experimented for 8 years but were made a mockery Thus, their work wasn’t discovered until the 1900’s, which was essentially 35 years of lost advancement History of Mendel’s Experiments Until Mendel, no one had a clear idea of how physical traits passed through generations People were puzzled about how a trait could ‘skip’ a generation Mendel 1. Formulated a specific question 2. Utilized “model organisms” * used pea plant - inexpensive - easy to use - pollinated by hand -edible 3. Quantifying his results showed it was a ‘hot chance’ Results of Mendel’s Experiment: He began with 2 groups of yellow and green seeds/plants Then he bred ‘true’ lines After he cross bread them Trait Cross 1rst Generation Seed Color Yellow & Green All Yellow Seed Shape Round & Wrinkled All Round Flower Color Purple & White All Purple He discovered that the dominant is more likely to occur & the recessive is less likely to occur Additionally, he found that the trait was not “lost” at all, it was simply not being shown 3:1 ratio of dominant to recessive Explanation: - Discovered genes - Pair (from the mother and the father) - Genes in one of two forms (either yellow which is dominant, or green which is recessive) Alleles- different forms of genes Explanation for all these was his greatest contribution Suggested that all physical characters of his plants were determined by genes (factors) that must exist in parts Gene- portion of an individual’s genetic makeup that controls a specific physical/psychological/biochemical trait (ex. seed color) - Each gene has two or more variants called alleles - Physical characteristics One allele from mom & dad (split genetic info 50/50); work as pair Alleles carried on chromosomes Karyotype- isolates chromosomes Meiosis- separation of alleles during sexual orientation Sperm & egg brought together Through the process of swabbing cheeks, we are able to see two alleles and 3 phenotypes Homozygote 1. Both Dominant 2. both same recessive showing recessive gene 3. one dominant, one allele shows dominant trait Ex. Y = Yellow (dominant) g = Green (recessive) The equation is like this… Y = Mom genotype Phenotype heterozygote Yellow g = Dad g = green homozygote Green g = green Modifying and Extending Mendel Mendel’s work was ignored for 35 years until it was rediscovered in the 1900’s in both the US 7 Europe Lead to series of follow up studies designed to test & extend his work Findings were that Mendel’s work was in fact correct, but also incomplete Later extensions & modifications have come to light Mutations: To Mendel, the allele for green & yellow seeds were permanent in terms of their phenotype De vries, an American biologist, found in primrose plants a trait that was nowhere in past generations In this case, their was a sudden appearance of purple flowers He called this a ‘mutation’, or a sudden change in an allele that’s passed to the next generation Ex. primrose plant (flower color) & fruit flies (eye color) Mutations occur rarely but regularly - How? - Well with about 1/5000 to 1/10000 alleles per generation thought to be a mutation, that means that if the human genome has 30,000 alleles than each person carries about 3-6 mutations Genetic Crosses: Ready for Quantitive results Process of crossing the homozygote dominant (YY) with the homozygote recessive (gg) Done through use of Punnett squares Ex. jhcgzhjgccczcxczxczxc Y Y g Yg Yg g Yg Yg Everything has the… Genotype: Heterozygote (Yg) Phenotype: yellow Heterozygote crosses: Punnett squares show how & why recessive traits skip generations; the allele is there but is hidden by a heterozygote because its recessive Ex. jhcjjhghjxgvhjgjxcvhjh Y G Y Yy Yg G Yg gg This time… Genotype: 1 homozygote dominant (Yy), 2 heterozygotes (Yg, Yg), and 1 homozygote recessive (gg) Phenotype: 3 yellow: 1 Green Homozygote 1. both dominant 2. both same recessive showing recessive gene 3. one dominant What are amphibians? Background info: There are about 4,200 different species of amphibians worldwide They bridge the gap between water (fish) and land (reptiles) Amphibian means “dual life” Animals such as Salamanders & toads belong in the class of Amphibia Most have “complex life cycles,” where egg hatches into larvae or tadpoles, then into a small version of the adult They are heavily dependent on wetlands for at least part of their life cycle Basic facts: Found everywhere from mountains to desserts, but most abundant in tropic (wetlands: rain forest) Amazing range in size, from <0.5 to over 3 ft. long & 10 lbs. Skin is moist to help pass oxygen to the blood & has many specialized glands for defense (poison arrow frogs) Amphibian behavior: Most would call these animals “primitive,” showing a variety of remarkable behaviors Ex. male frogs call for & often fight for mates in elaborate wrestling matches (refer back to video where frogs were trying to get one another on their backs) Additionally, females (and males) often provide high levels of parental care to their offspring (refer to video of father saving tadpoles & protecting them in his mouth) Amphibian declines: One of the most intensive areas of research Combination of climate change & emerging diseases Ranavirus & Chrytrid fungus
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