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46 Cards in this Set
- Front
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Directional selection |
Selection in which phenotypes at one extreme of the population distribution are favored |
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Disruptive selection |
Selection in which phenotypes at both extremes of the population distribution are favored |
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Founder effect |
random changed in allele frequencies resulting from establishment of a population by a very small number of individuals |
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Genetic drift |
Changes in gene frequencies from generation to generation as a result of random (chance) processes |
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Natural selection |
Th differential contribution of offspring to the next generation by various genetic types belonging to the same population. The mechanism of evolution proposed by Charles Darwin. |
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Homologous |
Similar in position, structure, and evolutionary origin but not necessarily in function. Pairing at meiosis and having the same structural features and pattern of genes. |
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Monophyletic |
Pertaining to a group that consists of an ancestor and all of its descendants |
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Paraphyletic |
Pertaining to a group that consists of an ancestor and some, but not all, of its descendants |
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Phylogeny |
The evolutionary history of a particular group of organisms or their genes. |
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Synapomorphy |
A trait that arose in an ancestor of a phylogentic group and is present (sometimes in modified forms) in all of its members , thus helping to delimit and identify that group. Also called a shared diverted trait. |
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Goudwana |
A large southern landmass that existed from the Cambrian (540 MYA) to the Jurassic (138 MYA). Present day remnants are South America, Africa, India, Australia and Antarctica. |
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Half-life |
The time required for half of a sample of a radioactive isotope to decay to its stable, nonradioactive form, or for a drug or other substance to reach half of its initial dose |
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Laurasia |
The northernmost of the who large continents produced by the breakup of Pangaea |
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Pangaea |
The single large landmass formed when all the continents came together in the Permian period |
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Plate tectonics |
The scientific study of the structure and movements of Earth's lithospheric plates, which are the cause of continental drifts. |
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Allopatric speciation |
The formation of two species from one when reproductive isolation occurs because f the interposition of (or crossing of) a physical geographic barrier such as a river . Also called geographic speciation. |
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Evolutionary radiation |
an increase in taxonomic diversity or morphological disparity, due toadaptive change or the opening of ecospace. |
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Sympatric speciation |
Speciation due to reproductive isolation without any physical separation of subpopulations |
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Polyploidy |
The possession of more than two entire sets of chromosomes |
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Speciation |
The process of splitting one biological lineage into two biological lineages that evolve independently from one another |
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Genome |
the haploid set of chromosomes in a gamete or microorganism, or in each cell of a multicellular organism. |
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Similarity matrix |
the ground substance where things fill a space |
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Pseudogenes |
a DNA segment that is homologous to a functional gene but is not expressed because of changes to its sequence or changes to its location in the genome |
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Orthology |
genes that can betraced to speciation events |
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Paralogy |
genes that are related though duplication events |
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Endotoxin |
A lipopolysaccharide that forms part of the outer membrane of certain Gram-negative bacteria that is released when the bacteria grow or lyse. |
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Exotoxin |
A highly toxic, usually soluble protein released by living, multiplying bacteria. |
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Invasiveness |
The ability of a pathogen to multiply in a host's body. |
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Nitrifiers |
Chemolithotrophic bacteria that oxidize ammonia to nitrate in soil and in seawater. |
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Thermophile |
An organism that lives exclusively in hot environments. |
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Phenotypes |
What we observe in nature, physical expression of genes |
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Genotype |
Governs by traits |
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Gene pool |
a single individual has only some of the alleles found in the population to which it belongs |
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Stabilizing Selection |
Purifying selection |
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Directional Selection |
May favor a singular gene, positive selection ( Cows with big horns, dog breeding) |
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Disruptive Selection |
Individuals at both extremes of a population are simultaneously favored. ( birds who feed on hard and soft seeds; Black and white peppered moths) |
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Sexual selection |
acts on characteristics that determine reproductive success. ( Satin Bower Birds build nests to attract mates) |
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Bottleneck |
Populations that loose genetic variations due to environmental changes, resulting in a new species or extinction |
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Polyphyletic |
does not include its common ancestor |
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Convergent evolution |
Independently evolved traits subjected to similar selection pressures may become superficially similar |
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Taxon (plural, taxa) |
is any group of species what we designate or name ( e.g., Vertebrates) |
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Clade |
A taxon that consists of all the descendants of a common ancestor |
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Binomial nomenclature |
Gives every species a unique, unambiguous name. |
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Paleo magnetic dating |
Movement and reversals of Earth’s magnetic poles are recorded in igneous and sedimentary rocks at the time they were formed, by alignment of mineral grains and other characteristics. |
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Concerted Evolution |
In some gene families, the genes are evolving together, or in concert with one another |
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Biofilm |
Gel-like sticky polysaccharide martix that produces bacterial community and traps other cells. Bad stuff |
