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Topic 5
BIOL topic 5
| Question | Answer |
|---|---|
| speciation | the process by which new species arise, the formation of biodiversity |
| term for the process by which new species arise | speciation |
| speciation combines the study of | ecology, evolution and genetics |
| what links micro and macroevolutionary processes | speciation |
| what causes the initial divergence | geography, ecological drift |
| how does reproductive isolation evolve | zygotic profiles |
| what happens when hybridization occurs | more fit - new, less fit - new, non-viable |
| when is the process of speciation complete | when pops are reproductively isolated |
| when do we know 2 species are now two distinct species | when mating between the pops fail to produce viable, fertile offspring |
| modes of speciation | allopatric, sympatric, "spontaneous" |
| allopatric speciation | geographical isolation |
| what type of speciation occurs bc of geographical isolation | allopatric |
| what is the most common mode of speciation | allopatric |
| sympatric speciation | speciation that occurs in the same place |
| what type of speciation occurs in the same place | sympatric |
| what speciation is less common | sympatric |
| spontaneous speciation | special cases, polyploidization |
| if barrier is removes and pops come back in contact, they may remain distinct in what type of speciation | allopatric |
| in allopatric speciation, gene flow ____ and separate pops ______ ______ | gene flow ceases, evolve independently |
| interbreeding between separately evolved pops is prevented by | prezygotic and postzygotic mechanisms |
| what do prezygotic and postzygotic mechanisms prevent | interbreeding between separately evolved pops |
| disruptive selection results in 2 genetically distinct sub pops within a pop and they eventually diverge sufficiently to become 2 distinct species in what type of speciation | sympatric |
| what type of speciation results from disruptive selection | sympatric |
| what type of selection results in sympatric selection | sympatric |
| polyploidy can cause | sudden speciation |
| meiosis fails and organisms produce diploid gametes instead of gametes in what type of speciation | polyploidy |
| autopolyploid | if a 2n gamete is fertilized with another 2n gamete |
| if a 2n gamete is fertilized with another 2n gamete | autopolyploidy |
| why can only autopolyploid only mate with other autopolyploid | reproductive isolation |
| autopolyploid is common in | ferns and flowering plants |
| reproductive isolating mechanisms prevent | the mixing of gene pools |
| prezygotic isolation mechanisms | before fertilization and the production of a zygote |
| what isolation mechanism happens before fertilization and the production of a zygote | prezygotic |
| postzygotic isolation mechanisms | after fertilization and zygote formation |
| what isolation mechanism happens after fertilization and zygote formation | postzygotic |
| habitat isolation is what type of reproductive isolation | prezygotic isolation |
| behavioral isolation is what type of reproductive isolation | prezygotic |
| temporal isolation is what type of reproductive isolation | prezygotic |
| mechanical isolation is what type of reproductive isolation | prezygotic |
| hybrid viability is what type of reproductive isolation | postzygotic |
| hybrid fitness is what type of reproductive isolation | postzygotic |
| what is habitat isolation | prezygotic, species live in diff habitats so they rarely encounter one another |
| gall wasps use assortative mating with differences between pops that use diff host but was absent between those who use the same pplant, this is an ex of | habitat isolation, prezygotic isolation |
| sympatric isolation causes | prezygotic isolation |
| ex of behavioral isolation | frogs that are morphologically similar but have distinct mating calls, females only respond to the call of their own species |
| frogs who only mate with those who have to mating call of their own species exhibit behavioral isolation which is | prezygotic isolation |
| 2 species reproduce isolated where their geographical distributions overlap | temporal isolation |
| trees with diff pollen production times in the same region show temporal isolation which is | prezygotic isolation |
| 2 species of flowers attract diff pollinators due to differences in floral structure is an ex of | mechanical isolation, prezygotic |
| possible outcomes of hybridization | reduces viability, lower survivability, reduced fertility, can mate but offspring have reduced fitness |
| reduced hybrid viability, lower survivability is a possible outcome of | hybridization, postzygotic barriers |
| reduced hybrid viability and sterile is a possible outcome of | hybridization, postzygotic |
| hybrid breakdown, can mate but reduced fitness in offspring is a possible outcome of | hybridization, postzygotic |
| ex of reduced hybrid viability | frog species can mate with other species but will hybrid embryos typically die in development so no viable or fertile adult hybrids produced |
| ex of reduced hybrid fitness | pizzly bears, hybrids are fertile but have low fitness in sea-ice habitats |
| major species concepts | morphological, reproductive, phylogenetic/evolutionary |
| morphological species concept | species are discrete types of organisms, defines by unique reliable morphological characters |
| most traditional species concept | morphological |
| advantages of morphological species concept | practical, simple to use |
| disadvantages of morphological species concept | no clear genetic or evolutionary justification, choice of character by be arbitrary, some species cannot be diagnosed morphologically |
| biological species concept | species are groups of actually or potentially interbreeding natural pops that are reproductively isolated from other such groups |
| what species concept says species are groups of actually or potentially interbreeding natural pops that are reproductively isolated from other such groups | biological species concept |
| what is the most used species concept | biological |
| advantages to biological species concept | clear criteria, clear evolutionary justifications |
| disadvantages of biological species concept | may be difficult to distinguish in the field, does not apply to many forms of life that reproduce asexually |
| phylogenetic species concept | based on the reconstruction of the evolutionary tree of an organism using morphological and genetic sequence data |
| which species concept is based on the reconstruction of the evolutionary tree of an organism using morphological and genetic sequence data | phylogenetic |
| phylogenetic species | a cluster of pops the emerge from the same small branch on a phylogenetic tree |
| term for a cluster of pops the emerge from the same small branch on a phylogenetic tree | phylogenetic species |
| advantages to phylogenetic species concept | more useful when thinking of asexual species, can apply it to any group of organisms, does not require knowledge of interbreeding |
| what species concept is most useful for asexual species | phylogenetic |
| disadvantages of phylogenetic species concept | detailed histories have been described for only few groups of organisms, potential for splitting species into very small groups based on slight differences |
| subspecies | local variants of species. when geographically separated pops of a species exhibit recognizable differences. interbreed but have diff selective pressures |
| ex of subspecies | polar bear, grizzly bear |
| term for local variants of a species | subspecies |
| ring species | species that have a ring-shaped distribution that surrounds uninhabitable terrain |
| term for species that have a ring-shaped distribution that surrounds uninhabitable terrain | ring species |
| adjacent pops of ____ ____ can exchange genetic material directly, but ___ ____ between distant pops occur only through ______ pops | ring species, gene flow, intermediatory pops |
| clinal variation usually results from | geneflow between adjacent pops experiencing diff conditions |
| what type of variation occurs from gene flow between adjacent pops experiencing diff conditions | clinal variation |
| cline | pattern of variation of a trait across geographic gradient |
| term for pattern of variation of a trait across geographic gradient | cline |
| clinal ex | coloration and patterning are important adaptive characteristics, plains zebra have clinal variation in striping patterns |
| species in nature can be hard to | define |
| no one species concept is _____ for all groups | correct |
| what species concept is extremely useful for the study of speciation | biological species concept |
| think of species as | hypotheses we can test |
| prezygotic and postzygotic isolating mechanisms prevent | interbreeding between species and maintain species integrity |
| what is a vicariance event | the development of a physical barrier which divides the once-continuous geographical range of a species |
| sympatric speciation in a pop can be prevented by | stabilizing selection of the pop as a whole |
| what type of reproductive barrier separates a pair of species found in the same habitat that could interbreed except that one mates at duck and the other at dusk | temporal isolation |
| under the biological species concept, what unifies a species | all individuals can interbreed and produce fertile offspring |
| what species concepts is preferable because it has clear evolutionary justifications | biological |
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