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28 Cards in this Set
- Front
- Back
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What is your definition of a species?
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Have members that mate with each other and can have a fertile offspring
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What concepts are used to distinguish from different species?
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Phylogenetic concept
biological species concept Evolutionary species concept Ecological species concept |
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What is Phylogenetic concept?
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Species are identified by having a unique combination of traits
looks at what they look live |
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What is Biological species concept?
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A species is a group of individuals whose members have the potential to interbreed with one another in nature to produce viable, fertile offspring but cannot successfully interbreed with members of other species
Reproductive isolation prevents breeding with other species |
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What is Evolutionary species concept?
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A species is derived from a single lineage that is distinct from other lineages and has its own evolutionary tendencies and historical fate
Fossil record or DNA sequence analysis |
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What is Ecological species concept?
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Set of organisms adapted to a particular resource
Occupy an ecological niche Within their own niche, members of a given species compete with each other for survival Useful for bacterial species, which reproduce asexually |
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What are two reproductive isolating mechanisms?
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Consequence of genetic changes as species adapts to its environment
by prezygotic Barriers and postzygotic barriers |
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What is prezygotic barriers?
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Prevent formation of zygote
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What is Postzygotic barriers?
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Block development of viable, fertile individuals
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What are Five type of Prezygotic barriers?
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habitat isolation
temporal isolation Behavioral isolation Mechanical isolation Gametic isolation |
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What is habit isolation
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Geographic barrier prevents contact (water)
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What is Temporal isolation?
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Reproduce at different times, ex: Spring and Fall field cricket, Periodical cicadas
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What is Behavioral isolation?
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Behaviors important in mate choice
Changes in song |
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What is Mechanical isolation?
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Incompatibility between body parts
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what is Gametic isolation?
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Gametes fail to unite successfully, so zygote cannot form
Important in species that release gametes into the water or air |
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what are three different type of Postzygotic barriers?
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Hybrid inviability
Hybrid sterility hydrid breakdown |
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whats is hybrid invalildity?
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fertilized egg cannot progress past an early embryo
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What is Hybrid sterility?
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interspecies hybrid viable but sterile
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what are patterns of Speciation?
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anagenesis
Cladogensis |
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What is Anagenesis?
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Linear
Single species transformed into a different species over the course of many generations Response to changing environment |
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What is Cladogenesis?
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Branching
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What type of division are there for two or more species?
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Allopatric speciation
Sympatric speciation |
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What is Allopatric Speciation?
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Most prevalent method for cladogenesis (branching)
Requires a limitation of gene flow Genetic drift and natural selection may quickly lead to differences |
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What is Sympatric Speciation
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Occurs when members of a species that initially occupy the same habitat within the same range diverge into two or more different species
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What are two type of sympatic speciation?
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Ecological subdivision,
Polyploidy |
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What are two ways genetic drift occurs?
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Cause 1: Occurs when some members of a species become geographically separated, home range is divided
Cause 2: Founder effect, small population moves to a new location that is geographically separated |
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What is Ecological Subdivision?
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small scale ecological separation
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What is Polyploidy?
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Changes in chromosome number, occurs in plants
Hybrid species have set of chromosomes from each parent species |
