The Study of Biology Chapter 1

Life’s Organization Defining life is challenging because of the complex properties that emerge from the interaction of simple properties Emergent Property: characteristic of a system that does not appear in any of the system’s component parts Same materials, different properties, each increasing level is more complex than the one before, with new emergent properties at each level

Life’s Unity Living things share a set of key characteristics. 1. Display Organization [least complex] atom  molecule  cell  tissue  organ  organ system  multicellular organism  population  community  ecosystem  biosphere [most complex] 2. All living things are made of one or more cells. Unicellular: made up of 1 cell Multicellular: made up of many cells

Life’s Unity 3. Requires Energy & Nutrients Nutrient: substance that an organism needs for growth and survival but cannot make for itself Producers: organism that makes its own food using energy and nonbiological raw materials Photosynthesis: producers use light energy to make sugars from carbon dioxide and water

Life’s Unity Consumers: organism that gets energy and nutrients by feeding on tissues, wastes, or remains of other organisms Energy is not cycled – It flows through the world of life in one direction: from the environment through organisms, and back to the environment

Life’s Unity 4. Maintain Homeostasis Homeostasis: process by which organism keeps its internal conditions within tolerable ranges by sensing and responding to change If anything happens within or to an organism that affects homeostasis, processes to restore it begin. hot  sweat  cold  shiver

Life’s Unity 5. Respond to Environment 6. Reproduces Stimulus: Anything that is part of the internal or external environments and causes some sort of reaction by the organism Response: reaction to a stimulus 6. Reproduces Reproduction: processes by which individuals produce offspring Inheritance: transmission of DNA to offspring All organisms inherit their DNA from one or two parents DNA is the basis of similarities in form and function among organisms Small variations in DNA give rise to differences among individuals and among types of organisms

Life’s Unity 7. Grows & Develops Development: multistep process by which the first cell of a new multicellular organism gives rise to an adult Growth: increase in the number, size, and volume of cells 8. Adaptations Evolve over Time Adaptation: traits in a species that develop as a result of changes in the environment Makes the organism well suited for their environment and passed on to future generations

Remember! H omeostasis O rganization G rowth & development R esponds to stimuli A dapts C ells E nergy R eproduces

Life’s Organization Taxonomy: the science of naming and classifying species Genus: a group of species that share a unique set of traits Species: unique type of organism Together, these designate the species name – Homo sapien Always italicized, genus is always capitalized

Science of Nature Science: body of knowledge based on the study of nature. Critical Thinking: deliberate process of judging the quality of information before accepting it

Biology Biology: the study of life We also study the origin of life, structures of living things, how living things interact Biologist: one who studies the diversity of life Research diseases, develop technology, improve agriculture, preserve the environment

Scientific Method 1. Ask a question 2. Form a Hypothesis Scientific inquiry begins with observation. 2. Form a Hypothesis Hypothesis: testable explanation of a situation Inductive Reasoning: drawing a conclusion based on observation Prediction: statement, based on a hypothesis, about a condition that should exist if the hypothesis is correct Deductive Reasoning: using a general idea to make a conclusion about a specific case

Scientific Method 3. Evaluate the Hypothesis Model: analogous system used for testing hypotheses Variable: characteristic or event that differs among individuals or over time Independent Variable: manipulated by the experimenter, does not change Dependent Variable: results from or depends on changes to the independent variable. Control Group: group used for comparison. Experimental Group: group exposed to the factor being tested.

Scientific Method 3. Evaluate the Hypothesis Data: information gained from observations. Quantitative Data: represents a measureable QUANTITY (time, temperature, length, mass, area, volume, density) Qualitative Data: QUALITITIES or descriptions of what our senses detect (fuzzy, nice)

Scientific Method 5. Report 4. Draw Conclusions Do your results support the hypothesis? 5. Report Peer Review: process by which experimental procedures and the results are evaluated by other scientists in the same field or conducting similar research.

Scientific Method Real World Application In 1996, the FDA approved Olestra, a fat replacement manufactured from sugar and vegetable oil, as a food additive. Potato chips were the first product to have Olestra. Soon after, people began complaining of intestinal problems after eating the chips, and blamed Olestra.

Scientific Method Hypothesis: Olestra causes intestinal cramps Prediction: IF Olestra causes cramps, THEN people who eat Olestra should be more likely to get cramps than people who do not eat it. Experiment: Control Group: Eats regular chips Experimental Group: Eats Olestra chips Dependent Variable: cramps? Independent Variable: type of chips Results: 17.6% of control group got cramps, 15.8% of experimental group got cramps Conclusion: Percentages are about equal, people who eat either chip are likely to get cramps, the data does not support the hypothesis

The Nature of Science Scientific Law: A statement about a phenomena which is unchanging under given conditions. The Law of Conservation of Energy Scientific Theory: A scientifically acceptable explanation of a phenomena based on scientific observations and data. The Theory of Evolution Don’t be fooled! Not everything with scientific vocabulary is actual science. If claims, arguments, or methods presented do no follow scientific principles, it is pseudoscience – FAKE!