Term
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Definition
| a splitting event that creates two or more distinct species from a single ancestral species |
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Term
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Definition
| an evolutionarily independent population or group of populations |
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Term
| 3 criteria used to identify species |
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Definition
1. biological species concept
2. morphological species concept
3. phylogenetic species concept |
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Term
| biological species concept |
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Definition
| the main criterion for identifying species is reproductive isolation |
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Term
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Definition
| prevents individuals of different species from mating |
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Term
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Definition
| the offspring of matings between members of different species do not survive or reproduce |
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Term
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Definition
| researchers identify evolutionary independent lineages by differences in size, shape, or other morphological features |
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Term
| prezygotic isolation: temporal isolation |
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Definition
| populations are isolated because they breed at different times |
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Term
| prezygotic isolation: habitat isolation |
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Definition
| populations are isolated because they breed in different habitats |
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Term
| prezygotic isolation: behavioral isolation |
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Definition
| populations do not interbreed because their courtship displays differ |
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Term
| prezygotic isolation: gametic barrier isolation |
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Definition
| matings fail because eggs & sperm are incompatible |
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Term
| prezygotic isolation: mechanical isolation |
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Definition
| matings fail because male & female reproductive structures are incompatible |
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Term
| postzygotic isolation: hybrid viability |
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Definition
| hybrid offspring do not develop normally & die as embryos |
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Term
| postzygotic isolation: hybrid sterility |
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Definition
| hybrid offspring mature but are sterile as adults |
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Term
| 3 disadvantages of morphospecies concept |
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Definition
1. it may lead to the naming of two or more species when there is only one polymorphic species with differing phenotypes
2. it cannot identify cryptic species which differ in traits other than morphology
3. the morphological features used to distinguish species are subjective |
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Term
| phylogenetic species concept |
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Definition
| identifies species based on the evolutionary history of the population |
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Term
| monophyletic group/clade/lineage |
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Definition
| an ancestral population, all of its descendants, & only those descendants |
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Term
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Definition
| a trait that is found in certain groups of organisms & their common ancestor but is missing in more distant ancestors |
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Term
| 2 advantages of phylogenetic species concept |
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Definition
1. it can be applied to any population
2. it is logical because different species have different synapomorphies only if they are isolated from gene flow & have evolved independently |
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Term
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Definition
| populations that live in discrete geographic areas & have distinguishing features such as colorations or calls but are not considered distinct enough to be called separate species |
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Term
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Definition
| populations that are geographically separated |
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Term
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Definition
| speciation that begins with geographic isolation |
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Term
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Definition
| the physical splitting of a habitat |
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Term
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Definition
| the study of how species & populations are distributed geographically |
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Term
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Definition
| each other's closest relative |
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Term
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Definition
| when species live in the same geographic area, or at least close enough to one another to make interbreeding possible |
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Term
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Definition
| speciation that occurs even though populations live within the same geographical area |
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Term
| 2 types of events that can initiate the process of sympatric speciation |
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Definition
1. external events, such as disruptive selection for extreme phenotypes based on different ecological niches
2. internal events, such as chromosomal mutations |
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Term
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Definition
| the range of ecological resources that a species can use & the range of conditions that it can tolerate |
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Term
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Definition
| when an error in meiosis or mitosis results in a doubling of the chromosome number |
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Term
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Definition
1. autopolyploid (when a mutation results in a doubling of chromosome number & the chromosomes all come from the same species)
2. allopolyploid (when parents belong to different species mate & produce an offspring with two different sets of chromosomes) |
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Term
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Definition
| natural selection for traits that isolate populations |
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Term
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Definition
| a geographic area where interbreeding occurs & hybrid offspring are common |
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