BIO103: Concepts in Human Biology - Lecture Notes Review

BIO103: Concepts in Human Biology - Course Overview and Chapter 1 Notes

Chapter 1: Human Biology, Science, & Society

Characteristics of All Living Things

• Possess a distinct molecular composition compared to nonliving entities.

• Require energy and raw materials for survival.

• Are fundamentally composed of cells.

• Maintain homeostasis.

• Exhibit responsiveness to their external environment.

• Have the capacity to grow and reproduce.

• Populations of living things undergo evolution over time.

Homeostasis

• Definition: Homeostasis is the ability of an organism to maintain a consistent internal environment in response to changing internal or external conditions.

• Dynamic Constancy: Homeostatic mechanisms regulate a variety of conditions in the fluids surrounding cells, including:

  • Temperature

  • Water and salt levels

  • Glucose concentrations

  • pH

  • Oxygen (O2) and Carbon Dioxide (CO2)

Living Things Are Grouped According to Characteristics

• Three Domains of Life: Bacteria, Archaea, and Eukarya.

• Fundamental Criteria Used for Classification:

  • Presence or Absence of a Nucleus:

    • Bacteria and Archaea lack a membrane-bound nucleus (prokaryotes).

    • Eukarya possesses a membrane-bound nucleus (eukaryotes).

  • Number of Cells:

    • Unicellular (single-celled organisms).

    • Multicellular (organisms composed of many cells).

  • Type of Metabolism: How organisms obtain and use energy and nutrients.

• Domain Eukarya Includes Four Kingdoms:

  • Protista: Unicellular and simple multicellular eukaryotic organisms (e.g., protozoa, algae, slime molds).

  • Plantae: Multicellular, eukaryotic, photosynthetic organisms.

  • Animalia: Multicellular, eukaryotic, heterotrophic organisms.

  • Fungi: Eukaryotic decomposers (e.g., molds, yeasts, mushrooms).

Classification of Humans (Homo sapiens)

• Hierarchical Classification:

  • Domain: Eukarya

  • Kingdom: Animalia

  • Phylum: Chordata

  • Class: Mammalia

  • Order: Primates

  • Family: Hominidae

  • Genus: Homo

  • Species: sapiens

• Genus and Species:

  • Species: The smallest unit of the classification system. Defined as one or more populations of organisms with similar physical and functional characteristics that can interbreed and produce fertile offspring.

  • Genus: The second smallest unit of classification.

  • All living human beings belong to the same genus and species: Homo sapiens.

Defining Features of Humans

• Bipedalism: The ability to stand upright and walk on two legs.

• Large Brain: Possess a brain that is large relative to body size.

• Capacity for Complex Language: Capable of both spoken and written complex language.

• Opposable Thumbs: The ability to grasp objects between the thumb and the tips of the fingers.

Human Biology Can Be Studied on Any Level of Biological Organization

• Levels of Biological Organization (from smallest to largest):

  • Atom

  • Molecule

  • Cell

  • Tissue

  • Organ

  • Organ system

  • Organism

  • Population

  • Community

  • Ecosystem

  • Biosphere

Structural Level of Organization

• 1. Chemical level: The smallest level, comprising atoms and molecules.

• 2. Cellular level: Formed by many types of molecules combined in specific ways to create cellular structures.

• 3. Tissue level: Consists of 2 or more cell types that cooperate to perform a common function. Tissues are composed of cells and their surrounding extracellular matrix (e.g., membrane lining, cartilage).

• 4. Organ level: Comprises 2 or more tissue types combined to form an organ. Each organ has a recognizable shape and performs a specialized task.

• 5. Organ system level: The body's organs are grouped into organ systems. These consist of 2 or more organs that function together (e.g., the digestive system ingests food, absorbs nutrients, and eliminates wastes).

• 6. Organism level: All organ systems function together to make up a complete, working human body, an organism.