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Living Environment PDF

169 Pages·2015·12.34 MB·English
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Living Environment Notes Mrs. J. Frydberg Living Environment Notes © 2015 J. Frydberg 2 Table of Contents Notes Chapter 1 – The Science of Biology 5 Chapter 18 – Classification 11 Chapter 2 – The Chemistry of Life 15 Chapter 7 – Cell Structure and Function 24 Chapter 8 – Photosynthesis 35 Chapter 9 – Cellular Respiration 40 Chapter 10 – Cell Growth and Division 45 Chapter 35 – Nervous System 49 Chapter 36 – Skeletal, Muscular, and Integumentary Systems 57 Chapter 37 – Circulatory and Respiratory Systems 63 Chapter 38 – Digestive and Excretory Systems 72 Chapter 39 – Endocrine and Reproductive Systems 81 Chapter 40 – Immune System and Disease 92 Chapter 11 – Introduction to Genetics 99 Chapter 12 – DNA and RNA 105 Chapter 13 – Genetic Engineering 115 Chapter 14 – The Human Genome 120 Chapter 15 – Darwin’s Theory of Evolution 125 Chapter 16 – Evolution of Populations 130 Chapter 17 – The History of Life 135 Chapter 3 – The Biosphere 143 Chapter 4 – Ecosystems and Communities 151 Chapter 5 – Populations 160 Chapter 6 – Humans in the Biosphere 163 3 4 Chapter 1 – The Science of Biology 1-1 What is Science? Biology – the study of life. It is the science that seeks to understand the living world.  The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions. Science is an organized way of using evidence to learn about the natural world. Observation is the process of gathering information about events or processes in a careful, orderly way. Data is the information gathered from observations. An inference is a logical interpretation based on prior knowledge or experience. A hypothesis is a proposed scientific explanation for a set of observations. A hypothesis must be in the form of a statement, not in the form of a question.  Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time. All other variables should be kept unchanged, or controlled. 1-2 How Scientists Work Designing an Experiment:  Identify the problem to be solved by asking a question  Form a hypothesis (educated guess) – must be in the form of a statement  Set up a controlled experiment – the independent variable is the one that is manipulated or changed; the dependent variable is what we observe changing in response to the manipulated variable  Record and analyze results – collect observations and data  Draw a conclusion – use data to evaluate the hypothesis and make a conclusion Repeating Investigations It is necessary to repeat experiments/investigations to show the results are the same each time and ensure the results are reliable. Experiments should have a large sample size to increase precision. Example: Redi’s experiment on spontaneous generation (life from nonliving). In 1668, Francesco Redi challenged the idea of spontaneous generation using jars with meat (uncovered, covered, and with a gauze covering). It showed that maggots appeared on the meat when uncovered but not on meat when covered. Redi’s experiment: 5 In the 1700s, John Needham challenged Redi’s work, claiming spontaneous generation could occur under the right conditions. He boiled gravy to kill microorganisms but days later the gravy was filled with microorganisms. Lazzaro Spallanzani read about both expriements and showed microorganisms will not grow in boiled gravy when the flask is sealed but will grow when the flask is open. Many scientists argued his experiment was unfair because no air = no life. In the 1800s, Louis Pasteur used a curved neck flask to prove Spallanzani was correct. He boiled a broth which remained free of microorganisms for a year; once the curved neck was broken off the flask, microorganisms began to grow in the broth. A hypothesis can be considered a theory if it is well supported by observations and data from many investigations. Pasteur’s experiment:  In science, the word theory applies to a well-tested explanation that unifies a broad range of observations. 1-3 Studying Life Characteristics of Living Things Describing what makes something alive is not easy. No single characteristic is enough and many nonliving things share traits with living things.  Living things share the following characteristics:  Made of units called cells (unicellular and multicellular)  Reproduce (sexual and asexual)  Genetic code (DNA – deoxyribonucleic acid)  Grow and develop  Obtain and use materials and energy (metabolism)  Respond to the environment (stimulus)  Maintain stable internal environment (homeostasis)  As a group, change over time (evolution) 6 Some properties of life: Unicellular means single-celled. Multicellular means many-celled. Sexual reproduction involves cells from two different parents uniting to produce the new organism. Asexual reproduction involves only one parent. Metabolism is the combination of chemical reactions through which an organism builds up or breaks down materials as it carries out its life processes; it is all the activities an organism must perform to sustain life. A stimulus is a signal to which an organism responds. Homeostasis is the process by which organisms maintain a constant internal environment. Evolution is the ability of a group of organisms to change over time. Branches of Biology Various branches exist: zoologists – animals, botanists – plants, paleontologists – ancient life. Some fields focus on living systems at different levels of organization:  Biosphere – any part of earth where life can exist  Ecosystem – community and the nonliving environment  Community – populations that live together in an area  Population – group of same species in an area  Organism – individual  Groups of cells – tissues, organs, and organ systems  Cells – basic units of life  Molecules – groups of atoms; smallest unit of compounds  Some of the levels at which life can be studied include molecules, cells, organisms, populations of a single kind of organism, communities of different organisms in an area, and the biosphere. At all these levels, smaller living systems are found within larger systems. 7 Levels of organization: 8 Life Functions/Processes 1. Regulation – maintains homeostasis; control and coordination of all life processes 2. Nutrition – take materials from environment and change them to useful forms for growth and repair; includes ingestion, digestion, and egestion 3. Transport – substances move into, are distributed within, and move out of cells 4. Respiration – releasing chemical energy stored in nutrients 5. Synthesis – building complex substances from smaller ones 6. Growth – increase in organism size due to increase in cell size and/or cell number 7. Excretion – removal of metabolic wastes (CO2, water, salt, and nitrogen compounds) from chemical reactions 8. Reproduction – new individuals are made; this is the only life function that is NOT needed for the survival of the individual (but is necessary for survival of the species) 1-4 Tools and Procedures Common Measurement System Scientists need a common system of measurement in order to replicate each other’s experiments. The metric system is a decimal system of measurements whose units are absed on certain physical standards and are scaled on multiples of 10. Length = meter, mass = gram, volume = liter, temperature = Celsius. 8 Metric conversion chart:  Most scientists use the metric system when collecting data and performing experiments. Microscopes Microscopes are devices that produce magnified images of structures that are too small to see with the unaided eye.  Light microscopes produce magnified images by focusing visible light rays. Electron microscopes produce magnified images by focusing beams of electrons. Parts of a compound light microscope: The compound light microscope allows light to pass through the specimen and uses two lenses to form an image (magnification of about 1000 times). The electron microscope uses beams of electrons to produce an image that is usually 1000 times better than the light microscope. 9 Size range of cells and microscopy: Lab Techniques A cell culture is a group of cells grown in a nutrient solution. Cell fractionation is used to separate different cell parts. Cells are broken by a special blender, added to liquid in a tube, and then placed in a centrifuge which spins to separate the cell parts by density. Cell fractionation: 10

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