Overview of Biology

• Definition:
  • Biology is the scientific study of life. It encompasses various fields ranging from the microscopic level to the entire biosphere.
  • The term "Biology" combines the Greek words "bios" meaning life and "-logy" meaning study.

Major Fields of Biology

• Branches of Biology:
  • Botany: The study of plants.
  • Zoology: The study of animals.
  • Microbiology: The study of microorganisms.
  • Cell Biology: The study of cells.
  • Biochemistry: The study of biological reactions at the molecular level.
  • Ecology: The study of organisms and their interactions with the environment.
  • Genetics: The study of inheritance and variation in organisms.
  • Evolution: The study of changes in organisms over time.
  • Anatomy: The study of internal structures of organisms.
  • Physiology: The study of the functions of internal structures.
  • Pathology: The study of diseases.
  • Embryology: The study of developmental processes.
  • Virology: The study of viruses.
  • Taxonomy: The classification of living organisms.
  • Paleontology: The study of ancient life.
  • Molecular Biology: The study of biological molecules.
  • Histology: The study of tissues.
  • And many more: Biology includes a vast range of additional fields.

Understanding Living Things

• Key Question: What distinguishes living organisms from non-living things, like a rock?

Characteristics of Living Things

• Living organisms possess specific characteristics, often summarized by the acronym MRS GREN:

  • Movement:
  • The ability of organisms to move independently.
  • Respiration:
  • The process of breaking down nutrients to release energy.
  • Sensitivity:
  • The ability to detect and respond to environmental changes.
  • Growth:
  • The capacity to grow and increase in size.
  • Reproduction:
  • The ability to produce offspring of the same kind.
  • Excretion:
  • The process of removing waste products of metabolism.
  • Nutrition:
  • The intake of materials for energy, growth, and development.

• Example: A car can move and a crystal can grow, but these are not alive since they do not fulfill all characteristics of living organisms.

MRS GREN Worksheet

• The acronym MRS GREN can be used as a mnemonic to remember the seven characteristics of living things:

  • Movement: (e.g., running, crawling)
  • Respiration: (e.g., breathing in, burning body fuel)
  • Sensitivity: (e.g., responses to hot and cold)
  • Growth: (e.g., getting taller)
  • Reproduction: (e.g., having babies, fertilization)
  • Excretion: (e.g., urine, waste materials)
  • Nutrition: (e.g., eating food, vitamins, carbohydrates)

• Instructions:

  • Color code or categorize the examples based on the characteristics they represent.
  • Note that respiration can refer both to the act of breathing and cellular respiration, which involves burning energy from food.

Are Viruses Living Organisms?

• A discussion of whether viruses are classified as living things is ongoing in the field of biology. They possess some characteristics of life but not all (e.g., they cannot reproduce independently).

Classification of Living Things

• Kingdoms of Life: Organisms are classified into several kingdoms based on their biological characteristics:

  • Fungi: Eukaryotic and multicellular organisms.
  • Animalia: Eukaryotic and multicellular organisms.
  • Plantae: Eukaryotic and multicellular organisms.
  • Protista: Eukaryotic organisms that can be unicellular or multicellular.
  • Eubacteria: Prokaryotic and unicellular organisms.
  • Archaea: Prokaryotic and unicellular organisms often found in extreme environments.

• Kingdom Examples:

  • Fungi: Molds, mushrooms, yeast.
  • Plantae: Ferns, broad-leaved trees, mosses.
  • Animalia: Insects, horses, squids, earthworms.

Levels of Organization in Living Things

• Hierarchy of Life:
  • Atoms: The basic unit of matter.
  • Molecules: Combinations of atoms.
  • Cells: The basic unit of life.
  • Tissues: Groups of similar cells performing a specific function.
  • Organs: Structures composed of multiple tissue types.
  • Body Systems: Groups of organs that work together (e.g., digestive system).
  • Organism: An individual living entity.
  • Population: A group of organisms of the same species in a particular area.
  • Community: Different populations interacting in an area.
  • Ecosystem: A community along with its physical environment.
  • Biosphere: The global sum of all ecosystems.