Biology Notes
Intro to Biology
Learning Objectives
- Understand and describe:
- Fields of science and biology
- Characteristics of life
- Levels of organization
- Hierarchical classification system
- Scientific method
What is Science?
- Science (noun): Intellectual and practical activity encompassing the SYSTEMATIC study of the structure and behavior of the physical and natural world through OBSERVATION and EXPERIMENT.
- Science (verb): systematic process
- Not a belief system!
- Biology is the study of life.
Biology
- Biology's relevance in our lives.
Characteristics of Life
- Organized
- Acquire materials and energy
- Reproduce
- Respond to stimuli
- Homeostatic: Maintaining a stable internal environment.
- Feedback Loop: STIMULUS -> SENSOR -> RESPONSE
- Grow & develop
- Adapt to environment
Levels of Organization
- Biosphere: Regions of the Earth's crust, waters, and atmosphere inhabited by living organisms.
- Ecosystem: A community plus the physical environment.
- Community: Interacting populations in a particular area.
- Population: Organisms of the same species in a particular area.
- Organism: An individual; complex individuals contain organ systems.
- Organ System: Composed of several organs working together.
- Organ: Composed of tissues functioning together for a specific task.
- Tissue: A group of cells with a common structure and function.
- Cell: The structural and functional unit of all living organisms.
- Molecule: Union of two or more atoms of the same or different elements.
- Atom: Smallest unit of an element; composed of electrons, protons, and neutrons.
Classification
- Why classify organisms?
- 8.7 million species estimated (excluding bacteria), with 80% undiscovered.
- Aids in understanding processes based on similarities and differences.
Classification
- Taxonomy: The discipline of identifying and grouping organisms.
- Systematics: The study of the evolutionary relationships among organisms.
Hierarchical Classification System
- From most to least inclusive:
- Domain
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
- Note: Supergroups do not need to be memorized
Domains
- Bacteria:
- Prokaryote
- Prokaryotic cells of various shapes
- Adaptations to all environments
- Absorb, photosynthesize, or chemosynthesize food
- Unique chemical characteristics
- Archaea:
- Prokaryote
- Prokaryotic cells of various shapes
- Adaptations to extreme environments
- Absorb or chemosynthesize food
- Unique chemical characteristics
- Eukarya
Domains & Kingdoms
- Eukarya:
- Eukaryote
- Kingdom Protista:
- Algae, protozoans, slime molds, and water molds
- Complex single cell (sometimes filaments, colonies, or even multicellular)
- Absorb, photosynthesize, or ingest food
- Kingdom Fungi:
- Molds, mushrooms, yeasts, and ringworms
- Mostly multicellular filaments with specialized, complex cells
- Absorb food
- Kingdom Plantae:
- Certain algae, mosses, ferns, conifers, and flowering plants
- Multicellular, usually with specialized tissues, containing complex cells
- Photosynthesize food
- Kingdom Animalia:
- Sponges, worms, insects, fishes, frogs, turtles, birds, and mammals
- Multicellular with specialized tissues containing complex cells
- Ingest food
Hierarchical Classification System
| Classification Category | Characteristics |
|---|---|
| Domain Eukarya | Cells with nuclei |
| Kingdom Animalia | Multicellular, motile, ingest food |
| Phylum Chordata | Dorsal supporting rod/nerve cord |
| Class Mammalia | Hair, mammary glands |
| Order Primates | Adapted to climb trees |
| Family Hominidae | Adapted to walk erect |
| Genus Homo | Large brain, tool use |
| Genus species Homo sapiens* | Body similar to modern humans |
| *To specify an organism, you must use the full binomial name, such as *Homo sapiens*. |
Scientific Method
- Steps:
- Observe
- Hypothesize
- Investigate
- Evaluate/Conclusion
- Communicate
Scientific Method
- Hypothesis:
- A proposed explanation for an unexplained phenomenon.
- Developed based on observations, prior knowledge, and peer-reviewed publications.
- Needs to be testable.
Scientific Method
- Theory:
- Joins well-supported and related hypotheses.
- Requires a broad range of observations, experiments, and data for support.
- Dynamic: improved or modified as we learn more (a strength).
- Often misused in everyday conversation.
- Identify the three theories discussed in the chapter 1 reading