What is Science Science Branches of Science The study of the world around us Branches of Natural Science Natural Science Earth Science Life Science Physical Science 1 The Scientific Method The Problem: How do you get a cookie? A systematic approach to answer a question or problem The Steps of the Scientific Method 1.Determine the question or problem– the purpose of an investigation 2.Create a hypothesis Predicted outcome of the question 3.Design and conduct an experiment (Test) The steps you take to answer your question 4.Collect and analyze data (observations) Data—what you measure Analyze—determine what the data means 5.State a conclusion Was your hypotheses correct based on your data 6.Repeat work to confirm conclusion 2 The Scientific Method Test the Hypothesis • Under Control A controlled experiment tests only one factor at a time and consists of a control group and one or more experimental groups. Variables Variable is anything that can affect the outcome of an experiment Control Variable Æ remains the same Experimental Variable Æ changes during the experiment The Building Blocks of Life 3 The characteristics of living things All living things: 1. 2. 3. 4. 5. 6. Heterotroph or autotroph ARE MADE OF CELLS RESPOND TO THEIR ENVIRONMENT REPRODUCE OBTAIN AND USE ENERGY GROW AND DEVELOP DNA—ability to pass on traits Life has to come from living things Autotrophs--organisms who can produce their own food (plants) Heterotrophs– organisms that obtain their food from autotrophs (animals) The Microscope /Light 4 Chapter 3 Section 3 The Organization of Living Things Cell Theory Organisms 1. All living things are made of cells 2. Cells are the basic unit in living things 3. All cells come from other cells • Anything that can perform life processes by itself is an organism. • An organism made of a single cell is a unicellular organism. A unicellular organism must carry out all life processes in order for that cell to survive. • In contrast, multicellular organisms have specialized cells that depend on each other for the organism to survive. Spontaneous generation=life coming from non-living things Cell Structure Prokaryotes—organisms who lack nuclei (Bacteria) No membrane bound organelles Small unicellular organisms Eukaryotes—organisms who have a nuclei Have membrane bound organellesmitochondria, chloroplast Can be multicellular 5 Prokaryote or Eukaryote Vocabulary: Parts of a cell OrganelleCell membrane- Prokaryote or Eukaryote? Parts of a cell Organelle- small structure in a cell that performs a specific function Similar to organs in our Body Cell membrane-layer surrounding the cell Controls what moves in and out of the cell CytoplasmCytoplasm-fills the space inside the cell NucleusNucleus- Large dark structure in the cell --Control center Chromatin— Chromatin—genetic material or DNA (Code for life) Mitochondria— Mitochondria—Power house of the cell Vacuoles— Cell wall- Vacuoles—store water and waste These are very large in plant cells Chloroplast- 6 What are the differences between plants and animal cells? Chloroplasts—converts sunlight into chemical energy—plant cells only Cell Wall- in plants and some bacteria (not animals) Protects the cell and gives it strength and rigidity Vacuole—Much larger in plants Label the following organelles and their functions Label the following organelles and their functions 7 How Big are They ? 8 Onion Elodea 9 Cheek 10 Chapter 3 Section 3 The Organization of Living Things Objectives • List three advantages of being multicellular. • Describe four levels of organization in living things. • Explain the relationship between the structure and function of a part of an organism. Chapter 3 Section 3 The Organization of Living Things Chapter 3 Section 3 The Organization of Living Things The Benefits of Being Multicellular Cells Working Together • Larger Size Larger organisms are prey for fewer predators. Larger predators can eat a wider variety of prey. • A tissue is a group of cells that work together to perform a specific job. • Longer Life The life span of a multicellular organism is not limited to the life span of a single cell. • Specialization Each type of cell has a particular job. Specialization makes the organism more efficient. 11 Chapter 3 Section 3 The Organization of Living Things Chapter 3 Section 3 The Organization of Living Things Tissues Working Together Tissues Working Together, continued • organ-- A structure made up of two or more tissues working together to perform a specific function •organ system-- A group of organs working together to perform a particular function •heart, stomach, intestines, brain, and lungs are. •digestive system, the respiratory system, and the cardiovascular system. • Leaves, stems, and roots Chapter 3 Section 3 The Organization of Living Things Chapter 3 Section 3 The Organization of Living Things Overview of Organ Systems Click below to watch the Visual Concept. Visual Concept You may stop the video at any time by pressing the Esc key. 12 Chapter 3 Section 3 The Organization of Living Things Chapter 3 Section 3 The Organization of Living Things Structure and Function, continued Structure and Function • In organisms, structure and function are related. • Structure is the arrangement of parts in an organism. • Function is the job that the part does. Chapter 3 Cells: The Basic Units of Life • The structures of alveoli and blood vessels enable them to perform a function. Together, they bring oxygen into the body and get rid of its carbon dioxide. Chapter 3 Cells: The Basic Units of Life Concept Map Use the terms below to complete the concept map on the next slide. prokaryotes cells do do not plants eubacteria humans bacteria eukaryotes 13
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