Biology 1101 Week 1 Notes
Biology 1101 Week 1 Notes BIOLOGY 1101 - 0100
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BIOLOGY 1101 - 0100
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This 9 page Class Notes was uploaded by Alexa Notetaker on Wednesday January 20, 2016. The Class Notes belongs to BIOLOGY 1101 - 0100 at Ohio State University taught by Dr. Kristin Smock in Spring 2016. Since its upload, it has received 127 views. For similar materials see Biology in Biology at Ohio State University.
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Date Created: 01/20/16
Biology 1101 Week 1 Notes Life is ORGANIZED: • Atoms • Molecule • Organelle • Cell ß smallest unit of life • Tissue • Organ • Organ system • Organism • Population • Community • Ecosystem • Biosphere Example: • I am an organism • Made up of organ systems: circulatory, reproductive, digestive, etc. • Organs: heart, intestine, kidney, ovaries • Tissues- cardiac muscles, fats, etc. • Cells- smallest unit of life- skin cells, cardiac cells, etc. • Organelles- different components of the cell that help it function (nucleus, mitochondria, etc.) • Molecule- made up of water, proteins, etc. • Each molecule is made up of atoms- water is made with 2 hydrogen and 1 oxygen (h20) Living things need and acquire ENERGY: • Every living thing must acquire energy to: o Build new structures o Repair old structures o Reproduce Example: when plants grow (takes energy), but then a bug eats a leaf (must repair or grow new leaf= energy) and to reproduce and make more plants all takes energy. Living things maintain internal constancy: • Must maintain internal conditions within certain boundaries • Homeostasis- state of internal constancy o Temperature- humans are usually around 98.6 degrees F o pH Levels- neutral is important to not burn ourselves (although some bacteria thrive in acidic environments because that is their “range of homeostasis”). Living things reproduce, grow and develop: • All living things come from other living things • DNA is copied and passed to offspring o DNA is the signature molecule of life Living things EVOLVE: • Examples of animals that are “perfectly suited” to their environment: o Hummingbirds with the perfect shaped beak for the flower they eat o Cheetahs are incredibly fast and high maneuverability skills in order to catch their prey o Polar Bears are able to blend in with environment with translucent fur but are able to absorb heat from the sun with black skin. o Mimic Octopus is able to shape-shift in order to scare off predators o Peppered moth is able to blend in with environment • Adaptation- inherited characteristics that enable organism to successfully survive and reproduce • Of all the individuals in a population, which ones will survive long enough to reproduce? o The ones with the best adaptations to the current and local environment. o Population: Group of individuals of all the same species that all interact with each other • EVOLUTION- change in the genetic makeup of a population over time o Natural selection is one mechanism of evolution o Thus, if genetic makeup changes over timeà evolution has occurred. o Good genes get passed on by survival of the fittest, and eventually the entire population has evolved. § Note that populations evolve, not just individuals Review: What is life? 1. Organized in a specific way 2. Need and acquire energy 3. Maintain internal constancy (Homeostasis) 4. Reproduce, grow and develop 5. Living things (populations) evolve How do we study the natural world? • Make observations o Anything that you see • Ask questions • Propose a hypothesis o Hypothesis- proposed explanation that is testable for a question • Come up with a prediction (“If hypothesis is true, then…”) • Set up experiment design… Design a controlled experiment: Experimental Design: • Sample size • Variables o Independent (manipulated) variable- What you are changing in the experiment o Dependent (response) variable- What you are testing for o Standardized variable- constancies that you are not changing (temperature, climate, amount of soil, water, sunlight, etc.) o Control- Add no independent variable to test in “natural environment” with no changes Interpret and Analyze Results: • Bring your results back to your hypothesisà does it support it? Draw Conclusions: • What can you say after conducting your experiment? o Note that you can NEVER say we have “proven” anything to be true. Publish Results: • Choose a journal to submit results, editor reviews and decides whether it is worthy or not… • If it is, it is submitted to a panel of experts in the field to be scrutinized… • Range of responses: could resubmit after you go through list of concerns in order to be published. • When you design an experiment on the scientific method, it is always repeatable. • If results are not reproducible, questions are asked on legitimacy and possible manipulation. Review: How do we study the natural world? 1. Make Observations 2. Frame a question that relates 3. Propose a hypothesis 4. Make a Prediction (“If…then…”) 5. Design and conduct an experiment 6. Analyze your results and draw conclusions 7. Submit for publication Hypothesis Vs. Theory: • Hypothesis- tentative, often narrow explanation regarding the natural world o Must be testable and falsifiable • Theory- a well substantiated explanation of some aspect of the natural world o A unifying explanation o The ideas about which scientists are most certain o Acts as an umbrella- ties together different ideas/hypothesis Example: Let go of an apple and it falls (fact) The apple falls because of gravity (theory) o Facts= data o Theory= explanation as to why Chemistry of Life: • Elements- pure substances that can’t be broken down by chemical means (examples: O, C, Na, H) • Atom- the smallest component of an element o Composed of subatomic particles § Protons (+) § Neutrons (neutral) § Electrons (-) • Atomic number- the number of protons in the nucleus • All atoms of a given element have the same atomic number • When protons equal electrons, the atom is neutral • When protons do not equal electrons, the atom is an ion (charged) Chemical bonds link atoms: • Atoms bond through chemical bonds- forces of attraction that hold atoms together • Molecule- 2 or more chemically bonded atoms o Example: water • We refer to molecule using their molecular formula o Example: water= H 2 Electrons determine bonding: • Electrons move around the nucleus in energy shells • Octet rule- atoms/ions are most stable when they have 8 e- in outer E shell (valence shell) o If valence shell is full, then it won’t react with other atoms o However, if there are spaces, then that atom is going to interact with other atoms in order to achieve the octet rule nucleus energy shells electron • If the outer energy shell is full, the atom is stable and will not react • If not, atoms/ions will lose, gain or share electrons to fill their outer shell • This is the basis of chemical reactions Covalent bonds: the sharing bond: • To satisfy the octet rule, some atoms will share elctrons o Shared e- travels around both nuclei o Single, double, trible bonds are represented by solid lines Example: Carbon- 4 vacancies Hydrogen- 1 vacancy Together they make CH 4 Unequal Sharing Bonds: • Atoms often have different electronegativity- the ability to attract electrons • Nonpolar covalent bond- both atoms have equal electronegativity o Example: in a tug-of-war game with equal strength on both sides • Polar covalent bond- unequal sharing of electrons o Unequal strength to one side Ionic Bond: The Stealing Bond: • If the difference in electronegativity is great enough, one atom will take an e- from another o Example: Na and Cl • Ionic bond results from the electrical attraction between 2 oppositely charged ions o Example: Chlorine has a greater electronegativity because sodium has 7 vacancies in the outer most shell, so chlorine is able to rip that electron from sodium to itself. This then fulfills the octet rule. § Chlorine is the “stealing” power • Sodium: more protons than electrons (+) • Chlorine: more electrons (-) Hydrogen bonds: Bonds of Attraction: • A hydrogen bond is a weak force of attraction between two atoms or ions with opposite partial charges o example: water molecule- polar covalent bond • Opposite partial charges attract on adjacent molecules, but they are weak o Example: Oxygen has greater electronegativity than hydrogen § Electrons spend more time around oxygen atom relative to hydrogen atom • Slight negative charge around oxygen atom because of this • Slight positive charge around hydrogen o Water molecules form weak attractions between each other, interacting among one another, forming weak hydrogen bonds Water: • Cohesion- water property as a result form the hydrogen bonds; water molecules “stick” together o Results from high surface tension § Example: insect has the ability to remain suspended above water § Example: Basilisk lizard (“Jesus Christ lizard”) is able to run above water Properties of Water: • Polar substances dissolve in water o Example: NaCl in water § Molecules of water surround each ion and separate them from one another § Note that this does not happen in other nonpolar molecules like oil in water • Substances that dissolve in water are hydrophilic (water-loving) o Examples: salt, sugar • Substances that do not dissolve in water are hydrophobic (water-fearing) o Example: oil, fats • Ice floats o As water molecules move around, they break and reform the hydrogen bonds o When temperature of water increases, the molecules move faster o When temperature drops, molecules slow down § When they slow down, they form crystalline lattices and the molecules are “arms-length” away from each other § In ice, there are fewer molecules per area, therefore, it is less dense • This is important because if the ice were denser than water and it sunk to the bottom of lakes, it would kill the community within the water
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