The Origin of Species
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| 6386515117 | The "Mystery of Mysteries" | Darwin: Mystery of Mysteries = first appearance of new beings on Earth | 0 | |
| 6386515118 | Speciation | process by which one species splits into two or more species - speciation explains the features shared between organisms due to inheritance from their recent common ancestor |  | 1 |
| 6386515119 | Microevolution | small changes in allele frequency in a population over time |  | 2 |
| 6386515120 | Macroevolution | broad large-scale patterns of evolutionary change generating new species | | 3 |
| 6386515121 | Species | "kind" or "appearance" - biologists compare morphology, physiology, biochemistry, and DNA sequences when grouping organisms |  | 4 |
| 6386515122 | Biological Species Concept | a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring - do not breed successfully with other populations - gene flow holds populations together genetically |  | 5 |
| 6386515123 | What is the main distinction that must occur for the origin and integrity of distinct species? | reproductive isolation | 6 | |
| 6386515124 | Reproductive Isolation | biological barriers that prevent two species from breeding and producing viable, fertile offspring - classified by whether barriers act before (prezygotic) or after (postzygotic) fertilization |  | 7 |
| 6386515125 | Hybrids | offspring of crosses between different species - reproductive isolation limits this! |  | 8 |
| 6386515126 | Habitat Isolation | two species do not or rarely encounter each other because they occupy different habitats (prezygotic) example: two species of garter snakes |  | 9 |
| 6386515127 | Temporal Isolation | species breed at different times of day, seasons or different years (prezygotic) example: Eastern and Western spotted skunks |  | 10 |
| 6386515128 | Behavioral Isolation | courtship rituals and other behaviors unique to a species prevent mating with others - mate recognition (prezygotic) example: Blue Footed Boobies |  | 11 |
| 6386515129 | Mechanical Isolation | mating attempt occurs, but morphological (structural) differences prevent successful mating (prezygotic) example: shells of two species of Snails Bradybaena |  | 12 |
| 6386515130 | Gametic Isolation | - sperm of one species may not be able to fertilize eggs of another species - sperm may not be able to survive in female's reproductive tract of another species (prezygotic) example: Sea Urchins |  | 13 |
| 6386515131 | Reduced Hybrid Viability | genes of the different parent species may interact and impair the hybrid's development or survival (postzygotic) example: salamanders - hybrids do not complete development |  | 14 |
| 6386515132 | Reduced Hybrid Fertility | even if hybrids survive and live, they may be sterile (postzygotic) example: male donkey and female horse produce a mule that is sterile |  | 15 |
| 6386515133 | Hybrid Breakdown | some first-generation hybrids are fertile, but when they mate offspring of the next generation are feeble or sterile (postzygotic) example: rice plants- left and right may produce small sterile plants (center) |  | 16 |
| 6386515134 | Allopatric Speciation | forms a new species due to geographical isolation example: formation of bridges, new lakes, emergence of mountain ranges |  | 17 |
| 6386515135 | Sympatric Speciation | result of genetic isolation without a geographical barrier example: part of pop switches to new habitat, new food, accident during cell division |  | 18 |
| 6386515136 | Allopatric "Other Country" Speciation | - gene flow is interrupted when a population is divided into geographically isolated subpopulations - the definition of a geographic barrier depends on the ability of a population to disperse example: canyon and small rodents vs. birds, coyotes or pollen - mutation and genetic drift can then occur and change the gene pool - natural selection will select the best-fit traits among the new group to survive - reproductive isolation may arise as a result | | 19 |
| 6386515137 | Sympatric "Same Country" Speciation | speciation takes place in populations that live in the same geographic area occurs when gene glow is reduced between groups that remain in contact - Polyploidy - Habitat differentiation - Sexual selection | | 20 |
| 6386515138 | Polyploidy | presence of extra sets of chromosomes due to accidents during cell division (nondisjunction in meiosis) - more common in plants than animals (but still rare!) example: oats, cotton, potatoes, tobacco and wheat |  | 21 |
| 6386515139 | Habit Differentiation | sympatric speciation can result from the appearance of new ecological niches (new habitat or resource not used by parent populations) example: North American maggot fly - can live on native hawthorn trees along with recently introduced apple trees | 22 | |
| 6386515140 | Sexual Selection | sexual selection can drive sympatric speciation sexual selection for mates of different colors has likely contributed to speciation in cichlid fish in Lake Victoria |  | 23 |
| 6386515141 | Hybrid Zones | a region where members of different species meet and mate and produce hybrid offspring |  | 24 |
| 6386515142 | Possible Outcomes of Hybrid Zones | 1. Reinforcement - barriers hold and hybrids disappear 2. Fusion - barriers give way and species fuse 3. Stability - barriers constant and continued production of hybrids |  | 25 |
| 6386515143 | Gradualism | species descended from a common ancestor and gradually diverge more and more in morphology as they acquire unique adaptations (Darwin) - small, gradual changes over long periods of time - long periods of time are needed for evolution - fossils should show continuous links - problem: gradualism doesn't fit the fossil record well (many "gaps") |  | 26 |
| 6386515144 | Punctuated Equilibrium | theory that deals with the "pacing" of evolution; evolution has two speeds of change: Gradualism: periods of apparent stasis or slow change punctuated by rapid bursts of speciation observed in the fossil record example: Trilobite evolution speciation can occur over a very short period of time (1 to 1,000 generations), too fast for the fossil record to record - fossil record will have gaps or missing links - established species will show gradual change over long periods of time |  | 27 |
