Overview
This lecture introduces the foundational concepts of biology, focusing on the properties of living things and the hierarchical levels of biological organization.
Properties of Living Things
- Living things have organized structures and are made of one or more cells.
- All living things respond to stimuli in their environment.
- Living organisms reproduce, either sexually or asexually, to create more of themselves.
- All living things adapt and evolve over time through the process of evolution.
- Growth and development occur in all living things, guided by genetic information (DNA).
- Regulation of internal functions is maintained by genetic instructions.
- Homeostasis is the maintenance of constant internal conditions (e.g., body temperature, pH).
- All living things process energy, such as through eating or photosynthesis.
Viruses and Living Things
- Viruses are not considered alive because they lack cells and do not perform all eight life properties.
Levels of Biological Organization
- Atoms are the smallest unit of matter with chemical properties.
- Molecules are formed by two or more atoms bonded together.
- Macromolecules are large molecules composed of smaller molecules (e.g., DNA, proteins).
- Organelles are small structures within cells that perform specific functions (e.g., mitochondria, nucleus).
- Cells are the smallest fundamental unit of structure and function in living things.
- Prokaryotic cells lack a nucleus and are simple (e.g., bacteria).
- Eukaryotic cells have nuclei and membrane-bound organelles (e.g., animals, plants).
- Tissues are groups of similar cells performing related functions.
- Organs are collections of tissues performing common functions (e.g., heart).
- Organ systems consist of functionally related organs (e.g., circulatory system).
- Organisms are individual living entities.
- Populations are groups of individuals of the same species in a specific area.
- Communities are sets of populations of different species inhabiting an area.
- Ecosystems include living organisms and non-living elements (e.g., water, air) in an environment.
- The biosphere is the collection of all ecosystems on Earth.
Key Terms & Definitions
- Homeostasis — ability to maintain constant internal conditions.
- Atom — smallest unit of matter retaining chemical properties of an element.
- Molecule — chemical structure of at least two atoms held together by chemical bonds.
- Macromolecule — large molecule formed by joining smaller molecules.
- Organelle — small structure within cells that carries out functions.
- Cell — smallest unit of structure and function in living things.
- Prokaryote — single-celled organism lacking a nucleus and membrane-bound organelles.
- Eukaryote — organism with cells that have nuclei and membrane-bound organelles.
- Tissue — group of similar cells carrying out related functions.
- Organ — collection of tissues performing a common function.
- Organ system — group of functionally related interacting organs.
- Organism — individual living entity.
- Population — all individuals of a species in a specific area.
- Community — set of populations inhabiting a particular area.
- Ecosystem — living things and non-living components in an environment.
- Biosphere — collection of all Earth's ecosystems.
Action Items / Next Steps
- Review key terms and their definitions.
- Prepare for the next chapter in the upcoming lecture.