Biology Chapter 1 Notes (Nicole Rogers)

THE MEANING OF BIOLOGY

  • BIO = LIFE
  • OLOGY = THE STUDY OF

CHARACTERISTICS OF LIFE

  • Organization
    • Are organized
    • Scientists like to organize things
    • All living things fall into a hierarchy of levels
    • Organization levels (from smallest to largest):
    • Atoms – smallest unit of an element, composed of electrons, protons, and neutrons
    • Molecule – the union of two or more atoms of the same or different elements
    • Cell – the structural and functional unit of all living things
    • Tissue – a group of cells with a common structure and function
    • Organ – a group of tissues functioning together for a specific task
  • Organization (continued)
    • Organ system – a group of organs working together for a specific task
    • Organism – Individual living thing
    • Population – Organisms of the same species in a particular area
    • Community – Interacting populations of different species in a particular area
    • Ecosystem – A community plus the physical environment (Abiotic and biotic factors)
    • Biosphere – Regions of the Earth’s crust, waters, and atmosphere inhabited by living things
  • Acquire Materials and Energy
    • Energy – the capacity to do work
    • All organisms require external material and energy sources to maintain their organization and carry on life’s activities
    • Organic Molecules (macromolecules or biomolecules)
    • 4 molecules: Proteins, Carbohydrates, Lipids, Nucleic Acids
  • Autotrophs (Producers)
    • Organisms that can use light or chemicals to create food
    • Example: plants and photosynthesis
  • Heterotrophs (Consumers)
    • Organisms that have to consume other organisms for food
  • Reproduce
    • Biogenesis – Life arises from life
    • Reproduction – the process by which an organism makes more of itself
    • Genes – units of information within an individual’s DNA
    • DNA – contains the hereditary copies of genes
  • Respond to Stimuli
    • Organisms respond to external stimuli
    • Behavior – response to stimuli directed towards minimizing injury, acquiring food, and reproducing
    • They move toward or away from a stimulus
    • Example: zebra runs from a lion
    • The photosynthetic portions of plants follow the sun as it moves across the sky
  • Homeostatic
    • Homeostasis = staying the same – the requirement that organisms maintain a relatively constant internal environment
    • What happens to the body when the internal temperature increases beyond normal range?
    • What happens to the body when the internal temperature decreases beyond normal range?
  • Grow and Develop
    • Growth = increase in size or number of cells
    • Part of development
    • Development = changes that take place from conception to death
  • Have the Capacity to Adapt
    • The earth’s environment is constantly changing
    • Some individuals within a species may be better fit in a new environment
    • Adaptations = Features that make an individual organisms better suited to the new environment
  • Natural Selection and Evolution
    • Natural Selection = the differential reproductive success of adapted individuals
    • Results in changes of characteristics of a population over time
    • Evolution = the change in frequency of traits in populations and species

CLASSIFICATION OF ORGANISMS

  • Organisms are assigned to groups based on their similarities
  • Systematics – the discipline of identifying and classifying organisms
  • Each organism is classified in a domain, kingdom, phylum, class, order, family, genus, and species
  • Taxonomy – the science of naming classified organisms
  • Uses a 2 part naming system known as binomial nomenclature
  • a binomial nomenclature creates a species name
  • There are 2 parts: Genus; Species ext{ epithet}
  • Domain
  • Kingdom
  • Phylum
  • Class
  • Order
  • Family
  • Genus
  • Species