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Chapter 1 The Science of life 1. List 6 unifying themes of biology – the study of life. A. Cell Structure and Function 1. All organisms are made up of cells. a. Some are unicellular, some multicellular. b. Cells of multicellular organisms underwent differentiation. i. Cells are small but highly organized. B. Stability and Homeostasis 1. All organisms have a way of maintaining stable internal conditions. This stable level of internal conditions is called homeostasis. C. Reproduction and inheritance – sexual and asexual – DNA and genes 1. All organisms reproduce. a. This is the process by which organisms transmit their hereditary information to their offspring. i. Hereditary information = DNA (deoxyribonucleic acid). a) A gene is short segment of DNA that contains the instructions for the development of a single trait. b) Sexual reproduction: genetic information from 2 parents is combined to form a new organism. c) Asexual reproduction: one cell gives rise to 2 new identical cells (no combining of DNA). D. Evolution – change over time by natural selection 1. Populations of organisms evolve, or change, over generations. Evolution helps explain how many kinds of organisms came into existence. 2. Evolution is generally thought to happen through the process of natural selection. a. Natural Selection: organisms with favorable traits live longer and are better able to reproduce than organisms that don’t have those traits. i. Evolution via natural selection generally comes about because of competition for resources. E. Interdependence of Organisms – ecology and ecosystems 1. Ecology: the study of the interactions of organisms with one another and with their environment. a. Specific environmental communities are called ecosystems. b. The stability of the environment depends on the organisms in the environment. c. The stability of the organisms depends on the availability of food, water, nutrients, and gases available to those organisms. F. Matter, Energy and Organization – complex organisms – autotrophs and heterotrophs 1. Living things need a constant supply of energy. 2. All energy comes from the sun, either directly or indirectly. a. Photosynthesis – the process of capturing energy from the sun and using it to make food. This is done by autotrophs. d. Heterotrophs are organisms that must consume other things, such as autotrophs, to get their energy. 2. List 7 characteristics of life and describe the main difference between the structure of a living thing and that of a nonliving thing. A. Organization 1. Organisms are highly organized and contain many complex chemical substances 2. atoms, molecules, organelles, cell, tissue, organ, organ system, organism - populations - communities - ecosystems B. Cells 1. All living organisms are made up of one or more cells 2. Fundamental units of life C. Organisms use energy - Energy = capacity to do work 1. Metabolism - the sum of all chemical reactions that occur in a cell (i.e. the breakdown of food for energy, or the use of the energy to make things happen in your body). 2. Ultimate source of energy for life on earth is the sun through photosynthesis D. Homeostasis - balance - maintenance of a stable level of internal conditions E. Growth 1. Cell division - Either via mitosis or meiosis. 2. Organisms have a definite form and a limited size 3. Development - the process by which an adult organism arises = Done via cell division and cell differentiation (specialization) 4. Organisms have a limited life span F. Reproduction - Necessary for the survival of the species. Sexual or asexual. G. Respond to their environment - helps organism survive 1. Adaptations a. Groups of organisms change over time b. Adaptations are modifications that make an organism suited to its way of life c. Natural selection is process by which species becomes modified over time 3. Explain how organisms get the energy they need to survive. A. photosynthesis – the capture of the sun’s energy and conversion to usable energy for living things B. autotrophs – organisms that obtain their own energy by making their own food some organisms (plants) convert water and carbon dioxide into sugars and starches C. photoautotrophs – use light energy like photosynthesis D. chemoautotrophs – use energy from inorganic substances such as hydrogen sulfide, ammonia and nitrogen compounds E. heterotrophs – organisms that must eat other organisms to get energy - either auto or heterotrophs F. metabolism – sum of all chemical processes that occur in an organism - some substances are broken down to yield energy for vital processes while other substances, necessary for life, are synthesized 4. Describe how a living thing is organized A. Organization – molecular and cellular levels – atoms, molecules, organelles, cell, tissue, organ, organ system, organism B. Followed by higher levels of organization – populations, communities, ecosystems, biosphere, Earth, planets, solar system, galaxies, universe 5. Explain why all living things on earth are not yet well understood A. Biodiversity 1. Measure of all living organisms in an area 2. There is a large number of unidentified organisms because of difficulty in finding them deep in the rainforests or deep ocean 6. Define and give examples of observing, measuring, organizing, and analyzing data, inferring and modeling. A. Observing – using five senses – sight, hearing, smelling, touch, tasting B. Measuring – quantitative data – can be measured in numbers C. Sampling – must be large and random to get a good cross section of the population D. Organizing data – graphs, charts, tables, maps E. Analyzing data – process of determining if the data is reliable and if it supports the hypothesis or not 1) Use statistics 2) Compare data with other studies 3) Determine possible sources of error F. Modeling – model is an explanation supported by data G. Inferring – inference is a conclusion made on the basis of facts rather than on direct observation 7. Explain the relationship between hypothesizing, predicting, and experimenting. A. Hypothesizing 1. Hypothesis – statement that explains observations that can be tested a. can be supported by evidence b. can not be proven without a doubt 2. forming a hypothesis – collect data that does or does not support the statement 3. predicting – statement made in advance that states the results – in the form of “if- then” a. two approaches to developing and testing hypotheses : i. inductive – gather empirical data and from it make generalizations ii. deductive – develop a general idea about a phenomenon, perform experiments, and from them make specific predictions that can be tested again B. Experimenting – process of testing a hypothesis 1. conducting a controlled experiment a. control group – standard of comparison with another group identical except one factor – the base group – not altered b. experimental group – group you changed one factor of from control group c. independent variable – the one that is manipulated i. factor that is different in control and experimental groups ii. the material one is working with during an experiment – the control iii. goes on the X axis d. dependant variable – the one that results from changes in the independent i. driven by or results from the independent variable ii. is what is being tested iii. changes with the independent variable iv. goes on the Y axis C. In short = order is make observations, write a hypothesis, make a prediction, then conduct a controlled experiment 8. Explain why good communication is so important in science A. Implementing Scientific Methods 1. Problem solving – more heads are better than one 2. Communicating – sharing of results – publishing in scientific journals – others can also test the hypothesis 9. Describe the methods that scientists use in their work. A. Scientific Method 1. Observing a. The act of noting or perceiving objects or events using the senses. b. Careful records must be kept of all observations in order to draw a conclusion or come to an answer. 2. Asking a Question a. Observations of the world usually raise questions. 3. Collecting data 4. Hypothesizing a. A hypothesis is an explanation that might be a true statement. b. A prediction is the expected outcome of a test, assuming the hypothesis is correct. 5. Experimenting – testing a hypothesis a. Data is needed. b. Controlled experiment- a controlled experiment always has a control group and an experimental group. 6. Drawing Conclusions a. Does the data support or reject the hypothesis (found out by analyzing the data). b. Model: a visual, verbal, or mathematical explanation supporting the data. c. Inference: a conclusion made on the basis of facts or premises rather than on direct observations. d. Inferences are not directly testable. 7. Implementing Scientific Methods a. Publishing Results b. Once a scientist completes an experiment, the results are often published for the scientific community to review. c. Many hypotheses that have been tested and confirmed many times by scientists eventually become a THEORY. d. A SCIENTIFIC LAW is a description of a natural phenomenon or principle that invariably holds true under specific conditions and will occur under certain circumstances. 10. Compare light microscopes with electron microscopes in terms of magnification and resolution. A. Microscopes – instrument that produces and enlarged image of an object 1. magnification – increase of an object’s apparent size 2. resolution – power to show details clearly 3. light microscopes – uses light of produce an image – used to view living things a. power of magnification – factor of enlargement/magnification 10x, 100x, 1000x 1. power of magnification of strongest objective lens X the power of magnification of the ocular lens 2. limited by the characteristics of light – wavelengths 4. electron microscopes – uses a beam of electrons to produce an image – cannot view living things a. transmission electron microscope – transmits a beam of electrons through a thinly sliced specimen and onto a screen b. scanning electron microscope – creates a 3-D image by spraying a whole specimen with a fine metal coating then a beam of electrons is passed over it and then projected onto a fluorescent screen 11. Explain the advantage of the Systeme International d’unites A. standard system of measurement called International System of Measurement (SI) 1. The SI unit system consists of seven base units, with a number of other units derived from those foundations. a) examples = meter, kilogram, second, Kelvin, mole 2. Derived units – produced by the mathematical relationship between two base units or between two derived units – used to measure surface area and velocity a) example = velocity is m/s (meters per second) b) using the base unit of length and the base unit of time to determine the length traveled over a given period of time. c) There are 7 fundamental base units in SI that describe length, mass, time, and other quantities: SI Base Units Base Quantity Name Abbreviation Length Meter m Mass Kilogram kg Time Second s Electric current Ampere A Thermodynamic temperature Kelvin K Amount of substance Mole mol Luminous intensity Candela cd Some SI prefixes Prefix Abbreviation Factor of base unit Giga G 1, 000, 000, 000 Mega M 1, 000, 000 Kilo k 1, 000 Hecto h 100 Deka da 10 Deci d 0.1 Centi c 0.01 Milli m 0.001 Micro 0.000001 Nano n 0.000000001 Pico p 0.000000000001 SI derived units often used in biology Derived quantity Name Abbreviation Area Square meter m2 Volume Cubic meter m3 Mass density Kilogram / cubic meter kg/m3 Specific volume Cubic meter / kilogram m3/kg o Celsius Degree Celsius C Other acceptable SI units Name Abbreviation Value in SI units Minute min 1 min = 60 s Hour h 1 hour = 60 min = 3, 600 s Day d 1 d = 24 h = 86, 400 s Liter L 1 L = 1 dm3 = 0.001 m3 Metric ton t 1 t = 1, 000 kg Biology Chapter 1 Review – The Science of Life Biology is the study of life, ranging from the study of unicellular organisms to the study of the global interactions among millions of organisms. Six themes serve to unify the study of biology: cell structure and function; (2) stability and homeostasis; (3) reproduction and inheritance; (4) evolution; (5) interdependence of organisms; and (6) matter, energy, and organization. The cell is the basic unit of life. Organisms may be unicellular or multicellular. Living things maintain a stable level of internal conditions, called homeostasis. Reproduction involves the transmission of hereditary information from organisms to their offspring. Populations of organisms evolve over generations primarily by a process called natural selection. Organisms interact in important ways with each other and with their environments. Living things have highly organized structures that are maintained by a constant input of energy. Autotrophs obtain energy by making their own nutrients. Heterotrophs obtain energy from the nutrients they obtain from their environment. Living things are composed of cells. Living things are more highly organized than nonliving structures. Living things use energy in a process called metabolism. Living things have several mechanisms that help them maintain stable internal conditions. When living things grow, their cells enlarge and divide. Living things reproduce, producing offspring similar to themselves. There is a great deal yet to be learned about the living world. Scientific investigations generally begin with observation. Methods scientists use in their work include observing, (2) asking a question, (3) collecting data, (4) hypothesizing, (5) experimenting, and (6) drawing conclusions. A hypothesis is a statement that explains observations and that can be tested. In a controlled experiment, the experimental group is identical to the control group except for one factor called the independent variable. Communication is very important in science because scientists build on the work of others. Vocabulary list Autotroph Evolution Organism Biology Experiment Photosynthesis Compound light microscop Experimental group Power of magnification Control group Heterotroph Prediction Controlled experiment Homeostasis Resolution Dependent variable Hypothesis Sampling Derived unit Independent variable Scientific method Development Inference SI Differentiation Magnification Theory Ecology Metabolism Ecosystem Model Electron microscope Observation
"Notes Chapter 1 The Science of life"