Chapter 1: Learning About Life
Biology
Ø Bios = life (from Greek)
Ø -logy/-ology = scientific study of a subject
Ø Biology = scientific study of life
The word science is derived from a Latin word “scio, scire” meaning to know
Science: Systematic study of the observable world and how it works
Science: Approach to learn about the natural world based on inquiry
Science: Body of knowledge and the process to acquire this knowledge
The Scientific Method
Process consisting of a series of steps used to answer questions
Ø Is not a rigid procedure
Ø Based on evidence to logically solve problems and answer questions
Steps of the Scientific Method
Observation
Question
Hypothesis: testable explanation of a natural phenomenon/educated guess
Prediction: statement about a condition that should occur if the hypothesis is correct
1’ Pose a scientific question
Theory: reliable explanation of important natural phenomena supported by extensive research Evolution by natural selection Atomic theory Cell theory
Fact: type of information considered to be objectively true based on current evidence Mushrooms are a type of fungus Cell membranes are made primarily of phospholipid molecules Chromosomes are found in the nucleus of eukaryotic cells
Independent variable: condition or treatment controlled by the experimenter/ treatment
Variable: a characteristic or event that differs among individuals or over time
Dependent variable: observed result that is influenced by the independent variable
Experiment: test designed to support or falsify a prediction
Experimental Constants: Aspects in the experiment that remain the same across all treatment groups and as trials are repeated
Sample size: number of individuals that are part of the experiment
Experimental group: receive a certain treatment or have certain characteristics
Controlled Experiments
Single-blind experiment: information about the experiment withheld from the participants
Double-blind experiment: neither the participants nor the experimenters know which group is the control group/ involves a third party
Control group: identical to an experimental group, but without exposure to the independent variable
Replication: Repeating the whole experiment
Baby Turtles: Do they swim or do they drift with the ocean currents?
Forms of Life Share Common Properties
Ø Atom Ø Molecule/ Biological
Molecules Ø Organelle/Cell*
§ Cells are the fundamental units of life
Ø Tissue Ø Organ
Order
Ø Organ system Ø Organism (Beyond the level of
organisms) Ø Population Ø Community Ø Ecosystem*
§ Producers § Consumers § Decomposers § Physical environment
Ø Biosphere
Reproduction, Growth and Development
Ø All living organisms have DNA (deoxyribonucleic acid) that carry hereditary information and guide: Ø Development: multistep process by which the first
cell of a new multicelled organism gives rise to an adult
Ø Growth: increase in the number, size, and volume of cells
Ø Reproduction: processes by which individuals produce offspring
Nutrients and Energy Processing
How do organisms obtain energy? Ø Producers Ø Consumers
Why do organisms need energy? Ø Power activities and
chemical reactions
Nutrient: substance acquired from the environment and required for growth and survival
All living organisms are capable of energy transformations and require nutrients to survive
Response to Environment
Response to a stimulus
Regulation/ Homeostasis
Living organisms have the ability to maintain a stable internal body environment even in the face of a fluctuating external environment
Evolution/ Adaptation to changing environment
Heritable traits that enable members of a population to better adapt to the changing environment Adapted individuals within a population will be more likely to survive, reproduce, and pass more of their genes on to the next generation
Major Themes in Biology
1. The Relationship of Structure to Function
The correlation of structure and function can be seen at different levels within biological systems
The indentations of the red blood cells increase the surface area through which oxygen would diffuse
Changing the shape of the active site of the enzyme renders the enzyme inactive
2. Information Flow Between all levels of biological organization
Information about glucose level in the bloodstream is received by the pancreas Pancreas releases insulin to regulate the amount of glucose in the blood
Information stored in the DNA is translated into proteins that control different body processes
3. Pathways that Transform Energy and Matter
Energy and matter transformations from one form to another makes life possible
4. Interactions within Biological Systems
Specific organization of components in a biological system and their interaction give rise to emergent properties
New properties that arise in each step upward in the hierarchy of life as a result of interactions between components and proper arrangement of components
Emergent Properties
“An organism is a living whole greater than the sum of its parts”
5. Evolution The process that has transformed life on Earth from its earliest forms to the vast diversity observed today Based on heritable changes
Evolution explains both the unity of life (descent from a common ancestor) and diversity of life (modifications that evolved as species diverged)
Darwin explained evolution by the process of natural selection
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