Diversity

• biodiversity?


  the number and variety of species and ecosystems on Earth
• species


  all organisms capable of breeding freely with each other under natural conditions
• hybridization

  the cross-breeding of two

  different species
• morphology


  the physical appearance

  and characteristics of an organism; also

  the science of the study of these physical

  characteristics
• evolutionary change


  a change that

  occurs in an entire population; usually

  occurs over a long period of time
• genetic diversity


  the genetic variability

  among organisms; usually referring to

  individuals of the same species
• heterotroph


  an organism that obtains

  energy-rich nutrients by consuming living

  or dead organisms
• autotroph


  an organism that uses sources

  of energy to produce nutrients from water,

  gases, and/or minerals
• species diversity


  a measure of diversity

  that takes into account the quantity of

  each species present, as well as the

  variety of different species present
• structural diversity


  the range of physical

  shapes and sizes within a habitat or

  ecosystem
• evolution


  the scientifi c theory that

  describes changes in species over time

  and their shared ancestry
• phylogeny


  the study of the evolutionary

  relatedness between, and among, species
• phylogenetic tree


  a diagram depicting

  the evolutionary relationships between

  different species or groups
• clade


  a taxonomic group that includes

  a single common ancestor and all its

  descendants
• biological classifi cation

  the systematic

  grouping of organisms into biological

  categories based on physical and

  evolutionary relationships
• taxonomy


  the science 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
• genus


  a taxonomic level consisting of a

  group of similar species
• binomial nomenclature


  the formal

  system of naming species whereby each

  species is assigned a genus name followed

  by a specific name; the two words taken

  together form the species name
• taxon ?


  a category used to classify

  organisms
• kingdom


  the highest taxonomic level

  of the traditional Linnaean system of

  classification
• dichotomous key


  a series of branching,

  two-part statements used to identify

  organisms (or objects)
• pathogen


  a disease-causing agent, often

  a virus or micro-organism
• mutualism


  a relationship between two

  species that live in very close association

  with each other, whereby each benefi ts

  from the association
• antibiotic

  a substance that can kill or

  weaken micro-organisms; natural antibiotics

  are produced by bacteria or fungi, whereas

  synthetic antibiotics are manufactured
• plasmid


  a small loop of DNA often found

  in prokaryotic cells; usually contains a

  small number of genes
• capsule

  an outer layer on some bacteria;

  provides some protection for the cell
• coccus

  a round bacterial cell
• bacillus


  a rod-shaped bacterial cell
• spirillum


  a spiral or corkscrew-shaped

  bacterial cell
• inorganic chemical


  a chemical that has

  an abiotic origin; some simple substances

  that are produced by organisms are also

  classifi ed as inorganic
• organic chemical


  in biology, any

  chemical that contains carbon and is

  produced by living things; carbon dioxide

  is an exception—it is produced during

  respiration but is classifi ed as inorganic
• obligate aerobe


  an organism that cannot

  survive without oxygen
• facultative aerobe


  an organism that can

  live with or without oxygen
• fermentation


  an anaerobic process that

  releases chemical energy from food
• obligate anaerobe


  an organism that

  cannot survive in the presence of oxygen
• binary fission


  the division of one parent

  cell into two genetically identical daughter

  cells; a form of asexual reproduction
• conjugation


  a form of sexual

  reproduction in which two cells join to

  exchange genetic information
• transformation


  a process in which a

  bacterial cell takes in and uses pieces of

  DNA from its environment
• horizontal gene transfer


  the transfer of

  genetic information from one species into a

  different species