Week 1 BIO 111 Notes

Seven Criteria of Living Organisms

  • Cellular Composition:

    • Living organisms must be composed of at least one cell.

    • Organisms can exist as unicellular or multicellular entities.

  • Response to Stimuli:

    • Living things must possess the ability to respond to external or internal environmental stimuli.

  • Reproduction:

    • Living organisms must have the capacity to reproduce and transmit genetic material to offspring.

  • Material and Energy Utilization:

    • Living organisms must utilize materials and energy from their environment.

    • Example: Plants capture and utilize energy from the sun.

    • Example: Humans acquire energy by consuming plants and animals.

  • Growth and Development:

    • Living organisms undergo defined growth and development throughout their life cycles.

    • Growth is defined as an increase in quantitative size: Grow=size\text{Grow} = \text{size}

    • Development is defined as qualitative functional or structural change: Develop=change\text{Develop} = \text{change}

  • Evolutionary Adaptation:

    • Organisms undergo evolutionary adaptation across generations to survive changing environments.

  • Regulation and Homeostasis:

    • Organisms must perform regulatory functions to maintain internal biological stability, known as homeostasis.

Biological Scale and Diversity of Life

  • Scales of Biological Inquiry:

    • Macro-scale biology focuses on large-scale historical and physical biological evidence, such as fossils, dinosaurs, and the duration of time living things have inhabited Earth.

    • Micro-scale biology focuses on microscopic interactions, such as bacteria and their interactions with antibiotics.

  • Biological Status of Viruses:

    • Viruses are categorized as non-living.

    • Viruses do not contain cells themselves and rely entirely on host mechanisms by hijacking a healthy cell.

    • The Human Immunodeficiency Virus (HIV\text{HIV}) utilizes RNA\text{RNA} rather than DNA\text{DNA} to replicate itself, causing it to mutate at a much faster rate.

  • The Three Domains of Life:

    • Taxonomists group the diversity of life into three overarching domains, representing the most inclusive biological level:

    • Bacteria

    • Archaea

    • Eukarya

  • Kingdoms Within Domain Eukarya:

    • Kingdom Animalia: Animals.

    • Kingdom Plantae: Plants.

    • Kingdom Fungi: Fungi, including organisms such as mushrooms.

  • Hierarchy of Biological Organization:

    • Biological systems are organized in a hierarchy from smallest to largest:

    1. Cell: The basic fundamental unit of life. Contrary to common assumptions, not all blood cells possess a nucleus; mature red blood cells lack a nucleus, are synthesized in bone marrow, and do not reproduce themselves.

    2. Tissue: Groups of similar cells performing a unified function.

    3. Organ: Structures composed of different tissue types working together.

    4. Organ System: Integrated teams of organs fulfilling broader vital functions.

    5. Organism: An individual living entity (representing a species).

    6. Population: A group of individuals belonging to the same species in a specific area.

    7. Community: All interacting populations across different species in an area.

    8. Ecosystem: All living organisms in a given area interacting with non-living physical components.

    9. Biosphere: The global sum of all ecosystems on Earth.

Scientific Methodology and Experimental Design

  • Definition of Science:

    • Science is a way of knowing and a systematic approach to understanding the natural world.

    • It relies on an evidence-based process to inquire into and investigate natural phenomena.

  • Sequential Steps of the Scientific Approach:

    1. Observations: Identifying patterns or phenomena in nature.

    2. Hypotheses: Proposing tentative explanations. Hypotheses are affirmed or negated; they are not proven or disproven.

    3. Testability Requirement: Proposed hypothesis statements must be testable through empirical means.

    4. Prediction: Deducing explicit expected outcomes.

    5. Experimentation / Observation: Testing predictions using experiments or additional observational studies.

    6. Analysis of Data: Evaluating results to determine whether the hypothesis is affirmed or negated.

  • Scientific Theories:

    • A scientific theory is broad in scope.

    • Theories are supported by a substantial and expansive body of evidence.

  • Experimental Variables:

    • Independent Variables: Factors explicitly manipulated by researchers, such as time, pH\text{pH}, or temperature.

    • Dependent Variables: The quantitative or qualitative metrics measured to judge experimental outcomes, which directly rely on changes in the independent variable.

  • Controlled Experiments:

    • Controlled experiments systematically compare an experimental group against a control group.

    • Subject Control Matching: Researchers match variable factors such as sex, age, and general health between control and experimental subjects.

    • Purpose: Experimental designs utilize matching and control groups to eliminate confounding variables and ensure research accuracy.

  • Science Versus Technology:

    • Goal of Science: To understand natural phenomena.

    • Goal of Technology: To apply scientific knowledge toward a specific practical purpose.

    • Relationship: Science and technology are interdependent, as technological advances stem directly from scientific discoveries.

Evolutionary Principles, Taxonomy, and Information Flow

  • Core Theme of Evolution:

    • Evolution represents the central unifying theme in biology.

    • Living organisms are simultaneously characterized by unity and diversity.

    • Evolutionary theory yields practical applications across medicine, species conservation, and agriculture.

  • Artificial Selection:

    • Humans act as agents of evolution through artificial selection (selective breeding) of crops and livestock.

    • Modern domesticated crops, livestock, and pets bear minimal physical resemblance to their original wild ancestors.

    • Example: Genetically modified (GMO\text{GMO}) seedless watermelons have been artificially selected to contain soft, small white seeds that do not require spitting out.

  • Taxonomic Hierarchy:

    • Acronym for remembering taxonomic ranks: "King Philip came over for good soup".

    • Taxonomic ranks in descending order of broadness:

    • Kingdom

    • Phylum

    • Class

    • Order

    • Family

    • Genus

    • Species

  • Human Classification Example:

    • Kingdom: Animalia (or Animal).

    • Phylum: Chordata or Vertebrae (both terms are acceptable, signifying the presence of a spinal cord or vertebral column).

  • Flow of Genetic Information:

    • Biological life relies fundamentally on the flow of genetic information.

    • Sequence of genetic flow: DNA→RNA→Proteins\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Proteins}

    • Molecular Interaction Loop: DNA\text{DNA} produces RNA\text{RNA}, RNA\text{RNA} synthesizes proteins, and proteins directly influence and preserve DNA\text{DNA}, maintaining a continuous regulatory cycle.

  • Matter and Energy in Ecosystems:

    • Life depends on the continuous transfer and transformation of energy and matter.

    • Ecosystems are uniquely characterized by the continuous cycling of matter.