ch. 1 study guide

Scientific Method

Introduction to the Scientific Method

The scientific method is a systematic approach used by scientists to explore observations, answer questions, and test hypotheses about the natural world. It is a process rooted in inquiry and evidence, rather than absolute proof.

• Science is derived from the Latin word for knowledge.

• It is a way of knowing and understanding the natural world.

• Involves making observations and testing hypotheses.

• The heart of science is inquiry.

Steps of the Scientific Method

• Testable: Hypotheses must be testable through experiments or observations.

• Repeated: Experiments should be repeatable for verification.

• Ongoing: Science is a continuous process of discovery.

• Communication: Results are shared with the scientific community.

• Human endeavor: Science is conducted by people and influenced by societal needs.

Flexibility of the Scientific Method

• Not all scientists follow every step in the same order.

• Community and societal needs can influence what is tested.

Key Terms

• Hypothesis: A tentative explanation that can be tested by experiments or observations.

• Theory: A well-supported hypothesis that unifies a broad range of observations and evidence.

• Law or Principle: A statement that links together observations for long enough and yields unvarying evidence.

Caveats of the Scientific Method

• Scientific models can only be proven false, never absolutely true.

• Correlation does not equal causation.

• Testable predictions cannot include the supernatural.

• The supernatural, by definition, is outside the realm of science.

• The term "theory" has a different meaning in science than in everyday conversation.

Reasoning in Science

Deductive Reasoning

Deductive reasoning starts with a general principle or assumption and applies it to specific cases. If the initial assumption is true, then the generalization is considered true for all specific instances.

• Generalization from specific

• Specific to general

• Impossible to prove generalization

Inductive Reasoning

Inductive reasoning involves making broad generalizations based on specific observations. It is used to form hypotheses and theories.

• Summarizes initial observations

• Creates a testable hypothesis

• More observations are made to test the hypothesis

• Experiments are conducted, and data is compared between experimental and control groups

• Results are interpreted to accept or reject the hypothesis

• Be cautious of placebo effects and bias

Characteristics of Living Things

Cellular Organization

All living things are composed of cells, which are the basic units of life. Cells can be unicellular or multicellular, and they are bounded by a membrane.

• Cells arise from pre-existing cells.

• Cells contain genetic material and carry out life functions.

Growth and Development

• Growth: Increase in size or number of cells.

• Development: Differentiation of cells and changes in function or structure.

• Can occur in different locations and involve changes in cell cycles.

Metabolism

Metabolism is the sum of all chemical reactions and energy transformations that occur within an organism.

• Includes both anabolic (building up) and catabolic (breaking down) processes.

Homeostasis

Homeostasis is the tendency of an organism to maintain a stable internal environment despite changes in external conditions.

Response to Stimuli

Stimulus: Any physical or chemical change in the internal or external environment that elicits a response from an organism.

• Examples: Light, temperature, chemicals, touch.

Reproduction

Reproduction is the process by which organisms produce new individuals. It can be sexual (involving fusion of sperm and egg) or asexual (without fusion).

• Genes are inherited from parents and transferred via cells.

• Multicellular organisms transfer information from one generation to the next.

Genetic Material: DNA

• DNA contains the genetic instructions for heredity.

• The nucleotide code is virtually the same in all living organisms.

Hormones and Intracellular Communication

• Hormones are chemical messengers that regulate physiological processes.

• Intracellular communication is used to send physical signals within and between cells.

Levels of Biological Organization

Biological systems are organized into a hierarchy, from the smallest chemical units to the entire biosphere.

Level	Description
1) Ecosystem	All living and nonliving components in a particular area
2) Communities	All populations of different species in an area
3) Populations	All individuals of a species in an area
4) Organism	An individual living thing
5) Organ	Group of tissues performing a specific function
6) Tissues	Groups of similar cells performing a function
7) Cells	Basic unit of life
8) Organelles	Specialized structures within cells
9) Molecules	Groups of atoms bonded together
10) Atoms	Smallest unit of matter

Summary Table: Characteristics of Life

Characteristic	Description
Cellular Organization	Composed of one or more cells
Metabolism	Chemical reactions and energy transformations
Homeostasis	Maintaining internal stability
Growth and Development	Increase in size and complexity
Response to Stimuli	Reacting to environmental changes
Reproduction	Producing new organisms
Genetic Material	DNA as the hereditary molecule

Key Equations and Concepts

• Scientific Notation: Used to express very large or small numbers, e.g., $1.23 \times 10^4$

• Basic Taxonomy: The classification of living things into hierarchical groups (Domain, Kingdom, Phylum, etc.)

Additional info: Some explanations and examples have been expanded for clarity and completeness, such as the definitions of metabolism, homeostasis, and the levels of biological organization.