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bio 201 l2.doc

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LECTURE 2 SCIENCE OF BIOLOGY Biology • Can be tiny microscopic ; Sharing planet with huge diversity ; Study of living organisms ( study of life, bio=science); to investigate living organisms Organization/Hierarchy of Life •Living organisms function and interact with each other at many levels •These levels are organized in a hierarchy of increasing complexity: • Atom(o), molecule(atp),  (H,C,N), (adenine), macromolecule(DNA), organelle(nucleus), (nerve cell)  cell(neuron), tissue(ganglion), organ(brain), organism(fish), population, community(coral reef), biosphere • Organismal level Tissue (nerve tissue) , organ (brain), organ system ( nervous system), organism • Populational level Population, species, community, ecosystem Cellular level • macro = large, large number of diff atoms in specific way • Put atom together get simple molecule ex hydrogen peroxide H2O • Blueprint of life, heredity • DNA found in nucleus (organelle with nuclear membrane) • Cell has plasma membrane ( may contain nucleus) Organismal level • Coordinate function together = nerve cell •  functions as result of cell -> tissue -> system Populational level • (Population) of geese  (species) = aquatic traits to swim • Insects w/ invertebrates ( community/ecosystem) external factors that affect Biological Diversity: Organization by Cell Types 1. Prokaryotes (bacteria, archaea) 2. Eukaryotes (brown algae, green algae, plants, amoeba, fungi, animals) • How to study biological diversity ? – look at cell (base unit of life in bio) • Unicellular (one cell) have all info needed to function Prokaryotic Cell Basic structure: •cell enclosed by… plasma membrane which lack … a NUCLEUS and NUCLEAR MEMBRANE and lack compartments –smaller and simpler in structure than eukaryotes –resemble the earliest cells to arise on earth most ancient biological organisms Ex Bacteria – • Cell membrane, cell wall, some have cell capsule, has nuclear region (DNA) • Makes protein from ribosome • Division by fission • No sexual so asexual reproduction genetic duplicates, cell divides pinch. Division of cell into 2 split clones produce clone genetically identical Eukaryotic Cell -larger, more complex … than prokaryotic cells -surrounded by a plasma membrane: semi permeable … separate animal cell from outside environment -has a nucleus , … nuclear membrane - has many membrane-enclosed compartments Eukaryotes: Plants Photosynthesis IN CHLOROPLAST • Photosynthesis produce oxygen • Carbon dioxide + water + light   respond to stimuli like wind sugar(glucose) + oxygen • Absorb energy from the sun and convert it to • CO2 + 6H2O+LIGHT energy it can use • C6H12O6+6O2 • Can do just fine without other organisms but • Plants SELF SUFFICIENT produce glucose other other organisms cant organism use Eukaryotes: Animals Eukaryotes: Fungi • Mobility, physics and metabolism (make internal • Obtain food from dead organisms some toxic heat) • Non photosynthetic, absorb nutrients from other • Cannot manufacture themselves, cannot make organisms their own food • Most are decomposers • Ingest other organisms, mobile, ie BEAR • Nutritional partners of numerous plants • mycorrhizae Eukaryotes: Protists • Catch other paramecium (uni) catch bacteria ; seaweed = multi cellular • •all eukaryotes that do not fit into the kingdoms of plants, animals, or fungi often grouped according to lifestyle • Unicellular (PROTIST) and multicellular (HUMAN) Biological Diversity related but different •emphasis on the concept of common ancestor •organisms are grouped in ways that attempt to define evolutionary … relationships Properties of Life cellular lifeBASIC properties : 1. Order and Cellular Organization are composed of at least one cell paramecium, protest  unicell 2. Metabolism/Energy Utilization chemical reactions, use of energy; prokaryotic chemical reaction in cytoplasm 3. Regulation and Homeostasis maintain stable internal conditions on of blood neutral 7.1-7.2 4. Reproduction, growth, and development maturity, reproduce 5. Heredity all living organisms possess a genetic system that is based on DNA or RNA 6. Response to the environment ex plants bend, move away from wrist ; all organisms respond to env stimuli 6. Evolve changing, adapting ; ability to adapt and change What about viruses? Are viruses alive? • Parasitic; Small, obligate, intracellular parasites • Partially living, have some characteristics of • Are not cellular, particles or agents living organism. Not cellular ( have great avility • Survive outside a host to evolve (HIV, flu) • #’s cannot increase without a host • Hereditary material – DNA or RNA • Adapted to exploit host cells • Adapt and evolve Science • Seeks natural causes for natural phenomenon (see, observe, manipulate, measure and verify, repeat) Stages of a Scientific Investigation SCIENTIFIC PROCESS Scientific Method 2.QUESTION –1. O observation ( be able to see) –2. H hypothesis ; Hunch or educated guess in watch How Scientists Think The Logic of Hypothesis Tests: researcher; integrates all knowledge (TESTABLE) •A hypothesis that fails our test is rejected and –3. P prediction considered disproven –4. E,T testing . experiments •A hypothesis that passes is supported, but not proven –5. C conclusion •Why not? An alternative hypothesis might be the real More people get same data, stronger prediction explanation Can have more than 1 virus, infectious, secondary •Experiments support the hypothesis that the common Hypothesis Testing generate as much data to support cold is caused by a virus hypothesis Figure 1.4 Experimentation •Experiments are contrived situations mimic •Variables: factors that can change in value under different conditions temp of water, oxygen in water, see of acquarium •Independent variables can be manipulated by the scientist ex. Weight gain in pigs, manipulate amount of protein •Dependent variables cannot be changed by the researcher amount of food weight gain Controlled Experiments •Controlled experiment: tests the effect of a single variable •Control: a subject who … is not exposed to the experiemental treatment •Differences can be attributed to THE EXPERIMENTAL TREATMENT Is There a Cure for the Common Cold? •no, but prevention methods are known •wash your hands •What is the effect on cold susceptibility of the following? –vitamin C INGESTING –cold temperatures EXPOSURE TO –exercise •Are there vaccines for the common cold? No vaccine for the common cold Antibiotics don’t work against virus only kills bacteria Hypothesis Testing • What is stress, how to
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