General Biology Study Guide: Classification, Scientific Method, Evolution, and Biological Organization

Classification of Life, Taxonomy, and Biological Organization

The 7 Properties of Life

Living organisms share several fundamental properties that distinguish them from non-living matter. These properties are essential for defining life:

• Order: Organisms exhibit complex but ordered organization.

• Reproduction: Living things can reproduce their own kind.

• Growth and Development: Organisms grow and develop according to inherited instructions.

• Energy Processing: Living things obtain and use energy to power activities.

• Response to Environment: Organisms respond to environmental stimuli.

• Regulation: Living things regulate their internal environment (homeostasis).

• Evolutionary Adaptation: Populations evolve over generations to adapt to their environment.

Levels of Biological Organization

Biological systems are organized in a hierarchy, from the smallest units to the largest:

• Biosphere: All environments on Earth that support life.

• Ecosystem: All living organisms and nonliving components in a particular area.

• Community: All populations of different species living in an ecosystem.

• Population: Individuals of the same species living in a specific area.

• Organism: An individual living thing.

• Organ System: Group of organs working together (e.g., digestive system).

• Organ: Structure composed of tissues performing a specific function.

• Tissue: Group of similar cells performing a function.

• Cell: Fundamental unit of life.

• Organelle: Membrane-bound structure within a cell (e.g., nucleus).

• Molecule: Cluster of atoms held together by chemical bonds.

Example: In humans, the heart (organ) is part of the circulatory system (organ system), made of cardiac muscle (tissue), which consists of cells containing mitochondria (organelle), composed of molecules like DNA.

Emergent Properties

Emergent properties arise at each level of biological organization due to the arrangement and interactions of parts. For example, a cell can perform functions that its individual molecules cannot.

Taxonomy: Domains and Kingdoms

Taxonomy is the science of classifying organisms. The three domains of life are:

• Domain Bacteria: Prokaryotic, unicellular organisms.

• Domain Archaea: Prokaryotic, often found in extreme environments.

• Domain Eukarya: Eukaryotic organisms, includes four kingdoms:

  • Kingdom Protista

  • Kingdom Plantae

  • Kingdom Fungi

  • Kingdom Animalia

Scientific Method

Steps of the Scientific Method

The scientific method is a systematic approach to inquiry:

• Observation: Gathering information about phenomena.

• Question: Formulating a question based on observations.

• Hypothesis: Proposing a testable explanation.

• Experiment: Designing and conducting tests to evaluate the hypothesis.

• Results and Conclusions: Analyzing data and drawing conclusions.

• Falsifiability: Hypotheses must be testable and potentially refutable.

Example: Testing whether sunlight affects plant growth by growing plants in light and dark conditions.

Major Themes of Biology

Unifying Theme

The unifying theme of biology is the study of life and its processes, emphasizing evolution as the core concept that explains the unity and diversity of life.

Evolution and Natural Selection

Natural Selection

Natural selection is the process by which organisms better adapted to their environment tend to survive and reproduce more successfully.

• Variation: Individuals in a population vary in traits.

• Inheritance: Traits are heritable.

• Differential Survival and Reproduction: Some traits confer advantages, leading to greater reproductive success.

Evolution by Natural Selection

Darwin's observations led to the theory of evolution by natural selection:

• Descent with modification

• Individual variation

• Overproduction of offspring

• Unequal reproductive success

• Adaptation

Example: Peppered moths in polluted environments show changes in coloration due to selective pressures.

Adaptations

Adaptations are traits that have evolved to enable organisms to survive and reproduce in specific environments.

Artificial Selection

Artificial selection is the intentional breeding of organisms by humans to produce desired traits.

Phylogenetic Trees

Phylogenetic trees are diagrams that show evolutionary relationships among species, identifying the most recent common ancestors.

Types of Mimicry

Mimicry is an adaptation where one species evolves to resemble another. Two main types are:

• Batesian Mimicry: A harmless species mimics a harmful one.

• Müllerian Mimicry: Two harmful species resemble each other.

Practice Essay Questions

1. List and explain each of the levels of biological organization. Use a specific organism as an example.

2. Explain the steps of the scientific method and apply the scientific method to an everyday life example.

3. A predatory bird is an environmental factor that a beetle population is exposed to. Explain what happens as the beetle population that originally consists of light, medium, and dark colored beetles when the environment is polluted with black soot. In your answer, include natural selection, reproductive success, individual variations, and evolution.

Domain	Kingdoms	Characteristics
Bacteria	-	Prokaryotic, unicellular
Archaea	-	Prokaryotic, often extremophiles
Eukarya	Protista, Plantae, Fungi, Animalia	Eukaryotic, unicellular or multicellular

Additional info: Some content was expanded for clarity and completeness, including definitions, examples, and a summary table of domains and kingdoms.