18-19 BIO TEST

• Speciation (reproductive isolation) - 1. geographic isolation (habitats) 2. behavioral isolation (mannerisms, mating rituals differ) 3. temporal isolation (mating times differ)
• Hox gene - regulatory gene that determines which parts of an EMBRYO develop into which body structures
• Allele Frequency - The number of times an allele occurs in the gene pool, compared to the total number of alleles in that pool.
• In the 1730s, Swedish botanist Carolus Linnaeus developed a two-word naming system called binomial nomenclature. 
• *In recent decades, biologists have been completing a changeover from that older system of names and classification to a new strategy based on evolutionary theory.
• In binomial nomenclature, each species is assigned a two-part scientific name. 

  By using a scientific name, biologists can be sure that they are discussing the same organism. Common names can be confusing because they vary among languages and from place to place. 
• The goal of systematics is to organize living things into groups (taxa) that have biological meaning.
•  A domain is a larger, more inclusive category than a kingdom.

  The three domains are Bacteria, Archaea, and Eukarya
•   The six-kingdom system of classification includes the kingdoms Eubacteria, Archaebacteria, Protista, Fungi, Plantae, and Animalia.
• Over time, Linnaeus’s original classification system would expand to include seven hierarchical taxa.  Linnaeus grouped species according to anatomical similarities and differences.
• The 7 levels of organizations - Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
• In a way, members of a species determine which organisms belong to that species by deciding with whom they mate and produce fertile offspring. 
• Modern classification looks beyond overall similarities and differences and group organisms based on DNA and evolutionary relationships.
• phylogeny — the study of how living and extinct organisms are related to one another. 
• phylogenetic systematics/evolutionary classification - group species into larger categories that reflect lines of evolutionary descent, rather than overall similarities and differences
• clade (monophyletic group) - a group of species that includes a single common ancestor and all descendants of that ancestor—living and extinct. (branch)
• cladogram -links groups of organisms by showing how evolutionary lines, or lineages, branched off from common ancestors.
• derived character -defines a clade and is a trait that arose in the most recent common ancestor of a particular lineage and was passed along to its descendants.
• single gene traits- a gene controlled by only one gene
• polygenic traits- a trait controlled by multiple genes
• natural selection - Organisms have multiple phenotypes for certain traits.  If anything in the environment favors one phenotype over another, it will be selected over time
• directional - one end of curve greater fitness (>) than those of other ends, shifts
• stabilizing selection - When individuals near the center of the curve have higher fitness.
• disruptive selection - When individuals at the higher ends have higher fitness. This type of selection can result in two separate groups within the same population, leading to speciation.
• genetic drift - Random change in allele frequency over time.

  Usually seen in small populations.
• genetic Equilibrium - If there are no selection pressures for or against a trait, the frequency of dominant (A) and recessive (a) alleles for a trait will be constant, and you can predict the genotypes of the next generation.

  (BASICALLY NOTHING HAPPENS)
• also factors of evolution - Nonrandom mating

  Small population size

  Immigration or Emigration

  Mutations

  Natural Selection

  Bottleneck effect (dramatic deduction in population and therefore genetic diversity)
• founder effect - colonization, shrinking of genetic diversity then diversity FROM THAT