Organisms, Classifcation and Autonomy

Learning Outcomes

  • Hierarchical Organization of Living Systems

    • From atoms to the biosphere.

  • Binomial Nomenclature

    • Understand and correctly write/interpret scientific names of organisms.

  • Taxonomy, Systematics, and Classification

    • Definitions and explanations.

  • Natural vs. Artificial Classification

    • Distinguishing characteristics.

  • Hierarchical Classification System

    • Levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

  • Concept of Species

    • Challenges in defining species.

  • Phylogenetic Trees

    • Interpretation and significance.

Characteristics of Life

  • Composed of cells.

  • Growth and development.

  • Regulation of metabolic processes.

  • Response to stimuli.

  • Reproduction.

  • Evolution and adaptation of populations.

Levels of Biological Organization

  • Molecular Biology

    • Atoms, Molecules, Macromolecules.

  • Cell Biology

    • Cells, Tissues, Organs, Organ Systems.

  • Ecology

    • Organisms, Populations, Ecosystems, Biosphere.

Basic Cell Theory

  • Cells as basic units of organization and function (Schleiden, Schwann).

  • All cells arise from pre-existing cells (Virchow).

  • Similar chemical composition and reliance on DNA/RNA.

  • Genetic information replication during cell division.

  • Overall organism's activity reflects total independent cell activity.

Types of Cells

  • Eukaryotic Cells

    • Complex organisms, possess membrane-bound organelles.

    • Example: Animals, Plants, Fungi.

  • Prokaryotic Cells

    • Simple structure, lack nucleus/organelles.

    • Example: Bacteria, Archaea.

Organization of Organ Systems in Mammals

  • Major Organ Systems:

    • Skeletal, Muscular, Nervous, Respiratory, Endocrine, Immune, Circulatory, Urinary, Integumentary, Reproductive, Digestive, Lymphatic.

Collection of Organisms

  • Population: Same species in a geographic area.

  • Community: Interacting populations.

  • Ecosystem: Community + non-living environment.

  • Biosphere: Combined ecosystems (Earth).

Nomenclature

  • Naming organisms essential for distinguishing them (over 2.16M species named).

  • Common names vary regionally; standardization aids scientific communication.

  • Latin used for naming (Historical context from mid-1700s).

Binomial Nomenclature

  • Developed by Carl Linnaeus; evolutionary relationships identified based on physical features.

  • Binomial Naming Format:

    • Genus (capitalized) and Species (lowercase) e.g., Puma concolor.

  • Italicized or underlined.

  • Abbreviations allowed for brevity (e.g., E. coli).

Taxonomy and Classification

  • Taxonomy: Focus on naming, describing, and classifying organisms.

    • Identification, nomenclature, classification.

  • Classification Methods:

    • Artificial Classification: Based on few traits, limited evolutionary reflection.

    • Natural Classification: Many traits, reflects evolutionary relationships.

Historical Development of Classification

  • Two kingdoms (Plantae and Animalia) to five kingdoms (Whittaker model) evolving into six kingdom systems delineating Archaea, Eubacteria, and Eukarya.

Biological Classification Hierarchy

  • Levels of Classification: Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species.

  • Example:

    • Dog: Canis lupus (Dog), Canis familiaris (Domestic Dog).

Phylogenetic Trees and Cladistics

  • Depict evolutionary relationships, based on shared characteristics.

  • Cladistics: Uses shared derived characteristics for classification.

  • Nodes indicate common ancestors; branches show lineage evolution.

Summary

  • Life organized on multiple levels from atoms to the biosphere.

  • Cell Theory: Composed of cells, cells as functional units, all cells derived from pre-existing ones.

  • Binomial nomenclature standard for species naming.

  • Taxonomy classifies organisms hierarchically.

  • Phylogenetic trees represent evolutionary relationships among organisms based on shared characteristics.