Term
| What are the two causes of speciation? |
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Definition
| Isolation and divergence of populations |
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Term
| Isolation results in what (with regard to migration)? |
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Definition
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Term
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Definition
| Reproductive isolation due to some physical (geographic) boundary preventing gene flow. May also occur when some members cross an existing barrier to establish a new population (founder event). This is the dominant form of speciation. |
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Term
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Definition
| Form of allopatric speciation whereby Earth's tectonic plates separate populations. |
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Term
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Definition
| Reproductive isolation due to the absence of a physical barrier. Often due to ecological or genetic differences (ie. in polyploidy individuals, where there is a duplication of chromosomes). May occur in conjunction with disruptive selection. |
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Term
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Definition
| Reproductive isolation occurring among geographically adjacent populations, often due to difference environmental conditions. |
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Term
| What is one important consequence that arises when reproduction isolation is incomplete? |
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Definition
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Term
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Definition
| Process by which reduced hybrid fitness generations selection favoring the evolution of stronger pre-zygotic reproductive barriers. |
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Term
| Pre-zygotic isolating mechanisms |
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Definition
| Prevent hybridization from occurring. |
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Term
| Post-zygotic isolating mechanisms |
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Definition
| Reduce the fitness of hybrid offspring, resulting in selection against hybridization. |
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Term
| What are the five types of pre-zygotic isolating mechanisms (explain each)? |
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Definition
1. Mechanical isolation: differences in size/shape of reproductive organs
2. Temporal isolation: differences in breeding seasons
3. Behavioral isolation: rejection of mates to to specific female preferences or the failure to recognize potential mates
4. Habitat isolation: two species have specific preferences for living/breeding habitats
5. Gametic isolation: sperm may not be physically or chemically capable of fertilizing an egg |
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Term
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Definition
| Developed by Linnaeus, a form of classification definied by the format: Genus species |
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Term
| What is the difference between taxonomy and phylogeny? |
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Definition
| Taxonomy deals with classifications and phylogenies are concerned with evolutionary relationships. |
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Term
| What are the 7 levels of classification and which is the most biologically meaningful level? |
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Definition
| Kingdom, phylum, class, order, family, genus, species (keep pond clean or froggy gets sick). Species is the most important form of classification (the other levels are arbitrarily defined). |
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Term
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Definition
| A named group of organisms to which individuals or sets of species are assigned. |
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Term
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Definition
| History of evolutionary relationships among organisms or their genes. |
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Term
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Definition
| Branching points that show where lineages diverged (speciation). |
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Term
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Definition
| Series of ancestral and descendant populations through time. Can be used for a single evolving species or several related species with a common ancestor. |
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Term
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Definition
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Term
| What is the difference between cladogenesis and anagenesis? |
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Definition
| Cladogenesis is speciation (when phylogenetic branches diverge) while anagenesis is change without speciation (straight lines in phylogenies) |
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Term
| What are the three ways we describe sets of taxa (explain)? |
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Definition
1. Monophyletic (clade): contains all the descendants of a common ancestor and only those descendants
2. Paraphyletic: contains some, but not all, descendants of a common ancestor
3. Polyphyletic: contains taxa whose members' last common ancestor is not included in the group |
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Term
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Definition
| More than two lineages branching from a common ancestor. |
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Term
| How are phylogenies inferred for a set of taxa? |
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Definition
| Through the use of character data, or diagnostic features of organisms. This includes morphological, developmental, and molecular features. |
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Term
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Definition
| Minimizes the number of evolutionary changes that must be reconstructed for all characters on a tree |
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Term
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Definition
| Similarity between organisms due to inheritance from a common ancestor |
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Term
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Definition
| A trait that was present in the ancestor of a group |
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Term
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Definition
| A trait found in a descendant that doesn't exist in the ancestor |
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Term
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Definition
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Term
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Definition
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Term
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Definition
| Trait unique to only one taxon |
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Term
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Definition
| Similar traits in distantly related taxa due to either convergent evolution or evolutionary reversal. |
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Term
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Definition
| Independently evolved traits subject to similar selection pressure that become superficially similar. |
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Term
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Definition
| When a character reverts from a derived state back to an ancestral state. |
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Term
| What is the difference between ingroups versus outgroups? |
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Definition
| Ingroups contain the organisms of primary interest while outgroups are used as comparisons to the ingroup. Outgroups are closely related, but not belonging to, the ingroup. |
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Term
| What are the benefits of using phylogenies? |
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Definition
1. They help reconstruct past events: discover origins of a new disease?
2. They allow us to compare and contrast living organisms
3. They reveal convergent evolution: when a trait arises multiple times is it an adaptation?
4. Conservation biology: how can variation best be preserved?
5. Co-evolving species |
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Term
| If traits are adaptations, we predict that they evolve in association to what? |
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Definition
| The environment to which the traits are adapted. |
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