evolution

• natural selection


  caused by: mutation, inheritance, selective pressure & production of offspring
• mutation - natural selection


  random mutation in DNA base pairs (some are more phenotypically significant than others)
• inheritance - natural selection


  mutation gives an advantage to survive & reproduce
• selective pressure - natural selection


  something in the environment that causes pressure to survive (e.g. predators, competition for resources)
• evidence of evolution can be...

  structural/comparative anatomy, comparative embryology, fossil records, biogeography, & DNA/protein sequences
• anatomical homology


  similar body structures among different species from a common ancestor
• biogeography


  is the study of the distribution of species and ecosystems in geographic space and through geological time
• cladogram


  diagram that shows the evolutionary relationships among a group of organisms
• convergent evolution


  process by which unrelated organisms independently evolve similarities when adapting to similar environments
• derived characteristics


  characteristic that appears in recent parts of a lineage, but not in its older members
• fossil record


  the geological record of organisms on earth that have been preserved in the rock in a chronological order (oldest on bottom layers and youngest on top layers)
• comparative embryology


  the branch of embryology that compares and contrasts embryos of different species, showing how all animals are related
• homology


  similar structure among different species from a common ancestor
• speciation


  formation of new species
• vestigial structure


  a structure that an organism has that is no longer useful to it, but that they have this structure because a common ancestor to that organism found it useful (Ex: Hip bones in whales)
• Law of Superposition

  a general law stating that in any sequence of sediments or rocks that has not been overturned, the youngest sediments or rocks are at the top of the sequence and the oldest are at the bottom
• fitness


  ability of an organism to survive and reproduce in its environment
• gene pool


  is the set of all genes, or genetic information, in any population, usually of a particular species.
• allele frequency


  number of times an allele occurs in a gene pool compared with the number of times other alleles occur
• competition for resources


  caused by limited environmental resources such as food or shelter
• coevolution


  the evolution of two or more interdependent species, each adapting to changes in the other (Ex: between insects and the flowers that they pollinate)
• geographic isolation


  form of reproductive isolation in which two populations are separated physically by geographic barriers such as rivers, mountains, or stretches of water
• bottleneck effect


  a type of genetic drift where there is a reduction of genetic diversity in a population that has just seen a significant reduction in size due to a random event such as a natural disaster
• Endosymbiotic Theory


  theory that helps explain the complexity of eukaryotic cells; it states that a photosynthetic prokaryote (bacteria) & an aerobic heterotrophic prokaryote (bacteria) were engulfed by an ancestral host cell; eventually becoming a chloroplast and mitochondria respectively; so some features of eukaryotic organelles are similar to prokaryotes
• "Primordial Soup" Hypothesis

  hypothesis about how the first simple organic molecules (amino acids) were formed