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Chapter 1 Exploring Life 1. Define biology 2. 3. 4. 5. Define living Scientific Inquiry Biological Hierarchy Biological Themes What is Biology? Definition Scientific study of LIFE What is Living? To be classified as living, these criteria must be met: 1. Highly ordered structure 2. Evolutionary adaptation 3. Respond to environment What is living? 4. Regulation of internal functions * Homeostasis 5. Process energy 6. Grow & Development 7. Reproduce * Hereditary Material Is a virus living? Why or Why not? How is Biology Studied? Science (“to know”) Includes 1. Body of knowledge 2. Scientific Inquiry process Search for information & explanation focus on specific questions Scientific Inquiry Two types 1. Discovery science Describe natural processes Observation Inductive Reasoning (generalizations from specific observations) “All organisms are made of cells” Scientific Inquiry 2. Hypothesis-based science Focus on explanations *Hypothesis Deductive Reasoning general to specific if ---> then “if all organisms are made of cells, then humans are composed of cells” Observations Questions Hypothesis # 1: Dead batteries Prediction: Replacing batteries will fix problem Test prediction Figure 1.25 Test falsifies hypothesis Hypothesis # 2: Burnt-out bulb Prediction: Replacing bulb will fix problem Test prediction Test does not falsify hypothesis Hypothesis-Based Science Idealized Scientific Method 1. 2. 3. 4. 5. Observation Question Hypothesis Experiment Conclusion Scientific Method 1. 2. 3. 4. 5. Must be testable Must be falsifiable Experiments must be repeatable Control effects of unwanted variables Supernatural phenomena is not addressed Data Two types of recorded observations 1. Quantitative 2. Qualitative Figure 1.24 Hierarchy of Biology Levels of Organization 1. Molecules 2. Organelles subcellular, specific functions 3. Cells Hierarchy of Biology 4. Tissues 5. Organs 6. Organ System Hierarchy of Biology 7. 8. 9. Organism Population Community Hierarchy of Biology 10. Ecosystem 11. Biosphere 1 The biosphere From the biosphere to organisms Figure 1.3 9 Organelles 1 µm Cell 8 Cells Atoms 10 µm 7 Tissues 50 µm 6 Organs and organ systems Figure 1.3 10 Molecules Themes of Biology Table 1.1 Themes of Biology 1. Cell Basic unit of life smallest unit that can perform all activities of life Figure 1.5 25 µm Two Cell Types 1. Prokaryotic no membrane bound nucleus no membrane bound organelles primarily bacteria Two cell types 2. Eukaryotic membrane bound nucleus several membrane bound organelles ex. Protists, fungi, plants, animals re 1.8 EUKARYOTIC CELL PROKARYOTIC CELL DNA (no nucleus) Membrane Membrane Cytoplasm Organelles Nucleus (contains DNA) 1 µm Themes of Biology 2. DNA is heritable information allows for continuity of life by transmitting biological information Nucleus DNA Cell Nucleotide (a) DNA double helix. This model shows each atom in a segment of DNA.Made up of two long chains of building A C T A T A C C G T A G T A (b) Single strand of DNA. letters are simple symbo small section of one chai Themes of Biology 3. Emergent properties refers to unique, new property of each hierarchy level not present at the simpler level Themes of Biology 4. Feedback Regulation kind of supply and demand economy regulate production of enzymes, proteins Two types: 1. Negative feedback (product turns it off) 2. Positive feedback (product speeds it up) Negative Feedback A Negative feedback Enzyme 1 B A Enzyme 1 B Enzyme 2 C C Enzyme 3 D D Figure 1.11 D D D D D D D D D Positive Feedback W W Enzyme 4 Enzyme 4 Positive feedback X X Enzyme 5 Enzyme 5 Y Y Enzyme 6 Z Z Z Z Z Z Z Z Figure 1.12 Enzyme 6 Z Z Z Z Z Z Z Z Z Z Z Themes of Biology 5. Interaction with environment interactions abiotic factors biotic factors 6. Energy and life Organisms must perform work Energy flow Themes of Biology 7. Unity in the Diversity of Life 15 µm 1.0 µm Cilia of Paramecium. The cilia of Paramecium propel the cell through pond water. 5 µm Figure 1.16 Cross section of cilium, as viewed with an electron microscope Cilia of windpipe cells. The cells that line the human windpipe are equipped with cilia that help keep the lungs clean by moving a film of debris-trapping mucus upward. Paradox of Unity & Diversity Unity 1. DNA is the genetic, heritable material, universal genetic code 2. Universal processes Replication, Transcription, Translation Paradox of Unity & Diversity Diversity vast collection of living organisms on Earth categorized into levels based on similarities Classifying Life Taxonomy – branch of bio that names and classifies species Domain Kingdom Phylum Class Order Family Genus Species Classifying Life 3 Domains 1. Bacteria - prokaryotes 2. Archaea - prokaryotes 3. Eukarya - eukaryotes Bacteria are the most diverse 4 µm and widespread prokaryotes and are now divided among multiple kingdoms. Each of the rod-shaped structures in this photo is a bacterial cell. DOMAIN ARCHAEA Figure 1.15 Many of the prokaryotes known 0.5 µm as archaea live in Earth‘s extreme environments, such as salty lakes and boiling hot springs. Domain Archaea includes multiple kingdoms. The photo shows a colony composed of many cells. Protists (multiple kingdoms) 100 µm are unicellular eukaryotes and their relatively simple multicellular relatives.Pictured here is an assortment of protists inhabiting pond water. Scientists are currently debating how to split the protists into several kingdoms that better represent evolution and diversity. Kingdom Plantae consists of multicellula eukaryotes that carry out photosynthesis, the conversion of light energy to food. Kindom Fungi is defined in part by the nutritional mode of its members, such as this mushroom, which absorb nutrientsafter decomposing organic material. Kindom Animalia consists of multicellular eukaryotes that ingest other organisms. Themes of Biology 8. Evolution accounts for diversity based on life’s unity Charles Darwin Figure 1.18 Evolution Charles Darwin in The Origin of Species articulated two main points: 1. Descent with modification 2. Natural selection Themes of Biology 9. Structure & Function – everything has purpose at all biological levels 10. Scientific Inquiry 11. Science, Technology, & Society – applications of science & production of technologies to benefit society