02/02 BIO

Introduction to Biology

  • East Tennessee State University

    • Bachelor’s degree in Chemistry earned here.

    • Open for communication during office hours.

    • Encouragement to reach out for help with problems.

  • Class Structure

    • Importance of communication regarding grading and assignments.

    • Mention of optional classes for student understanding.

    • Recognition of a missed week of school and adjustments to the exam schedule.

    • Announcement of upcoming Spring Break and Exam 4.

  • Assessment Methods

    • Cumulative final exam as an option to replace a lower exam score.

Characteristics of Life

  • Introduction

    • Life is challenging to define, but characteristics of living organisms can be identified.

    • Noted that biological properties are debated and continuously evolving; there are no fixed numerical definitions for life characteristics.

    • Importance of understanding these characteristics for the study of living things.

Key Characteristics of Living Things

  • Organization

    • All living organisms are composed of cells, as proposed by the cell theory.

    • Unicellular Organisms: Composed of a single cell (e.g., bacteria).

    • Multicellular Organisms: More complex, consist of many cells organized into tissues, organs, and organ systems.

    • Example: Pony as a multicellular organism vs. bathtub toy as non-cellular.

  • Homeostasis

    • Refers to the ability of organisms to maintain a stable internal environment.

    • Involves regulation of pH, temperature, and water concentration.

    • Example: Humans sweat to cool their body, while amoebas use their cell membranes.

    • Highlighted the absence of homeostasis in inanimate objects like toys.

  • Metabolism

    • The set of life-sustaining chemical reactions in organisms.

    • Autotrophs: Organisms like plants that convert light energy into chemical energy via photosynthesis.

    • Heterotrophs: Organisms like animals that consume other organisms for energy.

    • Mentioned that both types convert glucose into ATP through cellular respiration.

    • Example: Bath toy does not undergo metabolic processes.

  • Reproduction

    • Living organisms reproduce to create offspring.

    • Asexual Reproduction: Example of unicellular bacteria where DNA replicates, and the organism splits into two.

    • Sexual Reproduction: Example of ponies where fertilization of an egg by sperm results in a zygote.

    • Again, the toy does not reproduce and therefore does not fulfill this characteristic.

  • Growth and Development

    • Organisms grow and develop following genetic instructions inherited from their DNA.

    • Example: Baby ponies grow into adults based on their genetic material.

    • Contrast with the non-living toy which only varies in size but does not grow.

  • Response to Stimuli

    • The capability of organisms to respond to internal and external stimuli.

    • Explanation of internal stimuli such as hunger and external ones such as danger prompts responses (e.g., fleeing).

    • Mention of plants bending toward light as a response to stimuli.

  • Evolution

    • Defined as a self-sustaining system capable of Darwinian evolution (according to Dr. Gerald Joyce).

    • The gene frequencies in populations change over time due to natural selection, leading to adaptations.
      - Example: Bath toy cannot evolve as it lacks reproduction.

  • Controversy in Classification

    • Discussion on organisms that challenge the definition of life, notably viruses, which can reproduce only with a host.

    • Consideration of potential extraterrestrial life and whether it would share these characteristics.

Levels of Organization in Biology

  • Cell Level

    • Cells are grouped into tissues that perform specific functions.

    • Tissues combine to form organs, organs form organ systems, and organ systems create an organism.

  • Complexity from Simple to Complex

    • Atoms → Molecules → Cells → Tissues → Organs → Organ Systems → Organisms.

  • Ecological Organization

    • Population: A group of the same species in a specific area.

    • Community: Different populations together in an environment.

    • Ecosystem: Community plus abiotic factors.

    • Biosphere: All ecosystems on Earth.

Taxonomy and Classification

  • Basic Principles

    • Taxonomy defines the naming and classification of species, credited to Carl Linnaeus.

    • Classification has evolved with the advent of DNA research.

  • Hierarchy of Classifications

    • Domains include: Bacteria, Archaea, Eukarya.

    • Bacteria are prokaryotic and include various species that can be helpful or harmful.

    • Archaea are extreme prokaryotes with unique DNA structures, often extremophiles.

    • Eukarya (eukaryotes) are characterized by a defined nucleus and include diverse kingdoms.

  • Kingdoms

    • Protista: Diverse group, can be autotrophic or heterotrophic, predominantly unicellular.

    • Fungi: Heterotrophic, mostly multicellular, cell walls made of chitin.

    • Plantae: Autotrophic, multicellular with cell walls consisting of cellulose.

    • Animalia: Multicellular heterotrophs, including humans and hydra.

  • Binomial Nomenclature

    • Two-part naming system using Latin or Greek roots for species classification (e.g., Genus and species).

    • Importance in avoiding ambiguity from common names.

Conclusion

  • Encourage students to stay curious and engaged in the learning process. The dynamic nature of biology means that ongoing research and discoveries continually reshape our understanding.