U1 - Diversity of Living Things

• Phylogenetic tree


  A diagram depicting the evolutionary relationships between different species in groups.
• Phylogeny


  The study of evolutionary relatedness between and among species.
• Evolution


  The scientific theory that describes changes in species over time and their shared ancestry.
• Dichotomous key


  A series of branching, two-part statements used to identify organisms (or objects).
• Kingdom


  The highest taxonomic level of the traditional Linnaean system of classification.
• Taxon


  A category used to classify organisms.
• Binomial nomenclature


  The formal system of naming species, whereby each species is assigned a genus named followed by a specific name; the two words taken together form the species name.
• Genus


  A taxonomic level consisting of a group of similar species.
• Botanist


  A scientist specializing in the study of plants; also called a plant biologist.
• Biological classification


  The systematic grouping of organisms into biological categories based on physical and evolutionary relationships.
• Structural diversity


  The range of physical shapes and sizes within a habitat or ecosystem.
• Autotroph


  An organism that uses sources of energy to produce nutrients from water, gases, and/or minerals.
• Heterotroph


  An organism that obtains energy-rich nutrients by consuming living or dead organisms.
• Genetic diversity


  The genetic variability among organisms; usually referring to individuals of the same species.
• Evolutionary change


  A change that occurs in an entire population; usually occurs over a long period of time.
• Morphology


  The physical appearance and characteristics of an organism; also the science of the study of these physical characteristics.
• Hybridization

  The cross-breeding of two different species.
• Species


  All organisms capable of breeding freely with each other under natural conditions.
• Biodiversity


  The variety of life in the world.
• Taxonomy


  The study of classifying all organisms; taxonomists classify both living and fossil species.
• Botanist


  A scientist specializing in the study of plants; also called a plant biologist.
• Dichotomous key


  A series of branching, two-part statements used to identify organisms or objects (based on physical traits)
• pathogen


  disease-causing agent, often a virus or micro-organism.
• mutualism


  relationship between two species, each benefits from the association.
• antibiotic


  substance that can kill or weaken micro-organisms.

  natural antibiotics produced by bacteria or fungi.

  synthetic antibiotics are manufactured.
• plasmid


  small loop of DNA often found in *prokaryotic* cells; usually contains a small number of genes.
• capsule


  outer layer for some bacteria; provides some protection for the cell (also allows them to adhere to other objects)
• inorganic chemical


  chemical that has an abiotic origin; some simple substances produced by organisms are also classified as inorganic.

  (abiotic = resulting from non-living things)
• organic chemical


  any chemical that contains carbon and is produced by living things (biotic) with carbon dioxide as an exception.
• obligate aerobe


  an organism that cannot survive without oxygen
• facultative aerobe


  organism that can live with or without oxygen
• fermentation


  anaerobic process that releases chemical energy from food
• obligate anaerobe


  organism that cannot survive in the presence of oxygen.
• endospore


  dormant structure that forms inside certain bacteria in response to stress; protects the cell's chromosome from damage.
• capsid


  a protein coat that surrounds the DNA or RNA of a virus
• RNA (ribonucleic acid)


  nucleic acid found in all cells and some viruses; usually carries genetic information that provides instructions for synthesizing proteins.
• epidemic


  large-scale outbreak of disease; usually confined to a limited geographic region.
• pandemic


  epidemic that occurs over a widespread geographic area, often globally.
• bacteriophage


  a virus that infects bacteria.
• lysis


  the rupturing of a cell; can occur when newly made viruses are released from a host cell.