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Chapter 1. Introduction: Themes in the Study of Life. Biology. Scientific study of life Dynamic From complex organisms to the microscopic cells that compose them Modern but a history of almost 4 billion years. Life is associated with specific properties . Unifying Themes of Biology.
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Chapter 1 Introduction: Themes in the Study of Life
Biology • Scientific study of life • Dynamic • From complex organisms to the microscopic cells that compose them • Modern but a history of almost 4 billion years
Unifying Themes of Biology • Emergent properties • Interaction with environment and energy exchange • Correlation between structure and function • Cellular basis of life • Heritable information • System regulation (homeostasis) • Evolution – core theme • accounts for unity and diversity
Emergent Properties • New properties emerge at each level • Result from arrangement and interaction of parts as complexity increases • Not unique to biotic environment
Organisms interact with environment • Both organisms and their environments are affected by the interactions • The dynamics of an ecosystem include: • Cycling of nutrients • The flow of energy
Structure and function are correlated • Structure and function of living organisms are closely related
Cells are the basic units of life • Cell theory • Cell is lowest level of organization that can perform all activities required for life • All cells: • Are enclosed by a membrane • Use DNA as their genetic information • Have ribosomes to make proteins
25 µm • The ability of cells to divide is the basis for reproduction, growth, and repair of multi-cellular organisms
The continuity of life is based on heritable information • Chromosomes contain genetic material in linear segments of DNA (deoxyribonucleic acid) called genes • Genesare the units of inheritance
Regulation of Biological Systems • Negative feedback • Negates effect of stimulus • Most common in maintaining homeostasis • Positive feedback • Increases effect of stimulus
Evolution, the Core Theme of Biology • Charles Darwin: • Species showed evidence of “descent with modification” from common ancestors • “Unity in diversity” arises from “descent with modification”
Natural selection is the mechanism behind “descent with modification”
Unity in the Diversity of Life • DNA is the universal genetic language • Same basic “building blocks” • Similar metabolic pathways • Similar anatomical architecture
Scientific Inquiry • Inquiry is the search for information and explanation • Two main types of scientific inquiry: • discovery science (observations) • hypothesis-based science (experimental)
Discovery Science • Describes natural structures and processes • Based on observation and analysis of data • Qualitative, descriptions • Quantitative, recorded measurements
Hypothesis-Based Science • Observations lead us to ask questions • Hypothesis • Predictions that can be tested
Controlled Experiments • Compares experimental group with control group • Ideally, only one variable differs between the groups
Science, Technology, and Society • Science is knowledge • Technology is to apply scientific knowledge • Biology is marked by “discoveries,” while technology is marked by “inventions” • Has dramatic effects on society and may lead to ethical issues