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Bio 112 Exam 1
Bio 112 Exam 1 Terms (Basu)
| Scientific theory | - Broad, well-supported explanation w/ predicted value - Based on natural phenomena and causes - Stands up to experimental tests |
| 5 evolution misconceptions: | - Species are always evolving into better beings - Evolution creates new life thru mutations - Organism can evolve during its life - Organism can influence its evolution thru its responses (Lamarck) - Evolution is a random process |
| Evolution | Change in the genetic composition of a population from generation to generation |
| Carolus Linneaus | - Father of Taxonomy who created the first orderly classification system - Utilized binomial naming (i.e., Genus species) |
| James Hutton | - Geologist who focused on Gradualism (slow and continuous processes of rock formation) - Helped prove the Earth is really old |
| Charles Lyell | - Father of Geology - Focused on Uniformitarianism that expanded Hutton's ideas - Argued the rate of planetary geological changes /processes = the same rate of planetary geological changes/processes as today |
| Erasmus Darwin | Charles Darwin's grandpa who theorized idea of common life origin for evolution |
| Jean-Baptiste Lamarck | - Linked evolution to adaptations that were used for survival - Made theory of inheritance of "acquired" characteristics (physical changes on an organism's body were passed down) |
| Alfred Wallace | - Another scientist who sent Darwin his own similar ideas on natural selection - Recognized his ideas from biogeography |
| Charles Darwin | - First developed the theory of natural selection - Wrote Origin of Species (1859) which contained the 2 ideas of "Descent w/ Modification" (Evolution) & Natural Selection |
| Darwin's Origin of Species | - Darwin's publications on evolution and natural selection published in 1859 |
| "Descent w/ modification" | A phrase Darwin used in proposing that Earth's many species are descendants of ancestral species that were different from present-day species |
| Natural selection | Mechanism for evolution via reproduction of individuals w/ favorable genetic traits that survive environmental changes - Always leads to population adaptation |
| Phylogenetic tree | Diagram that shows evolutionary history of a species' common ancestors and closest relatives |
| Theory of evolution by natural selection | - Explains both diversity and unity of life - Accounts for much of life form and function - Can predict outcome of environmental change - Genetic variation (existing heritable variation) is essential for evolution by natural selection |
| Adaptation | An inherited feature that helps an organism's survival and reproduction in its present environment |
| Homologous structures | Structures derived from a common ancestor usually modified for different functions |
| Vestigial structures | Remnants of ancestral structures w/ no present adaptive function |
| Analogous structures | Structures modified for similar functions w/in unrelated species (no common ancestry) |
| Convergent evolution | Evolution from natural selection that acted in the same way from the same conditions for 2+ unrelated species - Results in analogous structures |
| Biogeography | Distribution of plant and animal species |
| Species | A group of organisms that can interbreed and produce viable, fertile offspring |
| Speciation | Formation of 2 species from one original species |
| Gene flow | Movement of alleles across a species' range |
| Allele | Gene variants that arise by mutation and exist at the same relative location on homologous chromosomes |
| Locus | The specific physical location of a gene on a chromosome |
| Morphology | Study of the size, shape, and structure of animals, plants, and microbes and of the relationship w/ their constituent parts |
| Biological vs. Morphological species | Biological species means organisms that are reproductively isolated from each other are different species, while Morphological species means organisms that have significant morphological/anatomical differences are different species. |
| Prezygotic vs. Postzygotic reproductive barriers | Prezygotic barriers act before the zygote is formed (via isolation), while Postzygotic barriers act after the zygote is formed (direct effects on hybrid) |
| Temporal isolation | Prez barrier which prevents interbreeding due to differences in breeding schedules |
| Habitat isolation | Prez barrier which prevents interbreeding due to differences in separated, occupied habitats |
| Behavioral isolation | Prez barrier which prevents interbreeding due to differences in certain actions/behaviors |
| Gametic isolation | Prez barrier which prevents interbreeding due to inability for sperm fertilization of eggs |
| Mechanical isolation | Prez barrier which prevents interbreeding due to physical incompatibility between reproductive organs of two organisms |
| Hybrid inviability | Postz barrier in which a produced embryo can't survive development (or barely survives) |
| Hybrid sterility | Postz barrier in which a produced embryo is birthed, but it can't reproduce (sterile or almost sterile) |
| Hybrid breakdown | Postz barrier in which a produced embryo is birthed and fertile, yet it's offspring are feeble/sterile |
| Allopatric/Geographic speciation | Speciation due to a population becoming isolated from the majority, preventing gene flow - Dispersal = few members move to a new geographical area - Vicariance = situation physically divides species |
| Sympatric speciation | Speciation occurring while the first species exists in the same geographical area - Rare in eukaryotes, prevalent in prokaryotes - Leads towards an isolated gene pool b/c both groups continue to live in the same area |
| Parapatric speciation | Speciation occurring in a gradual, adjacent, partially separation w/ limited gene due to different environmental pressures + shared border zone |
| Peripatric speciation | Speciation due to the isolation of a small group of individuals from a larger population and becomes isolated, usually at the edge of the larger population - Smaller than allo |
| Adaptive radiation | A process in which many adaptations evolve from single point of origin, causing the first species to radiate into several new ones |
| Hybrid zones | Areas (sometimes during allo spec) where 2 closely related species interact/interbreed |
| Zone reinforcement | A type of hybrid zone where hybrids are less fit than original species, and the species diverge due to strong reproductive barriers |
| Zone fusion | A type of hybrid zone where the reproductive barriers weaken until the 2 species become one |
| Zone stability | A type of hybrid zone where hybrids are fit and continue to be born (stabile reproductive barriers) |
| Aneuploidy | Chromosomal error that occurs when the gametes have too many/few chromos during meiosis, resulting in offspring having 2n+1 or 2n-1 chromos |
| Polyploidy | Chromosomal error w/ > 2 chromosome sets |
| Autopolyploidy | Polyploidy formed between 2 related but separate species |
| Allopolyploidy | Polyploidy formed between 2 individuals of the same species |
| Gradual equilibrium | Species diverge gradually thru time w/ small steps |
| Punctuated equilibrium | Species exhibit a large change in a relatively short period of time followed by long periods of no change |
| Gene pool | Collection of all the genes in a population |
| “Fixed” alleles | - Homozygous in all individuals - Only variant that exists for that gene in a population |
| Genotypic frequency | % of each genotype in a population |
| Allelic frequency | % of each allele in a population |
| Microevolution | Change in allele frequencies in a population over generations in short periods of time |
| Hardy-Weinberg Equilibrium | If a large population sexually reproduces at random, then the genetic frequencies should not change in the next generation |
| Conditions of Hardy-Weinberg Equilibrium | 1) No mutations 2) Random mating 3) No natural selection 4) Very large population size 5) No gene flow in/out |
| Mechanisms of microevolution | Natural selection, genetic drift, and gene flow |
| Genetic drift | Changes in genetic frequency often in small populations due to random events |
| Founder effect | An instance of genetic drift where a founder population breaks away from original source, leading to a random, less diverse population |
| Bottleneck effect | An instance of genetic drift where an event drastically reduces the populations' size, resulting in a smaller, less diverse population |
| Gene flow | Movement of alleles in/out of populations |
| Dependents for outcomes of natural selection | Relative fitness, forms of natural selection, sexual selection, and limitations of natural selection |
| Relative fitness | Reproductive contribution an individual passes to the next gen, relative to the others' success |
| Directional selection | A form of natural selection that shifts the population's genetic variance toward a new, fit phenotype - Selects for a phenotype at 1 end of a variation spectrum |
| Diversifying/Disruptive selection | A form of natural selection that maintains diversity and increases genetic variance w/ less fit intermediates |
| Stabilizing selection | A form of natural selection that decreases genetic variance w/ more fit intermediates |
| Frequency-dependent selection | A form of natural selection where phenotype fitness depends on how common it is in population (less common = more offspring) |
| Sexual selection | A form of natural selection where success is based on best traits for obtaining mates (leads to sexual dimorphism) |
| Intersexual vs Intrasexual selection | Intrasexual selection means individuals of 1 sex directly compete for mates of opposite sex, while Intersexual selection means individuals of 1 sex are finicky in selecting mates of opposite sex. |
| Sexual dimorphism | Phenotypic distinctions between one sex and another, including physiological and behavioural differences |
| Macroevolution | Mutation + Gene flow + Genetic drift + 3.8 B yrs |
| Hardy-Weinberg equations | p + q =1 (p^2) + 2pq + (q^2) = 1 |
| Phylogeny | Evolutionary history of a species & its relationship to other species depicted a a tree |
| Rooted vs. Unrooted phylogenetic trees | Rooted trees have a single lineage at their base to represent a common ancestor, while Unrooted trees have no common ancestor yet still show relationships |
| Three Domains of Life | Bacteria, Archaea, and Eukarya |
| Root | Indicator of a phylo's ancestral lineage |
| Branch point/Node on phylogenetic tree | Point where 2 lineages diverge |
| Basal taxon | A lineage that evolved early and remained unbranched |
| Sister taxa | 2 lineages that stem from the same branch point |
| Polytomy | A branch w/ >2 lineages |
| Systematics | The study of phylogenetic relationships |
| Clade/Monophyletic group | A group that includes a common ancestor and all its living/extinct descendants |
| Paraphyletic group | A group that includes a common ancestor and and some, but not all, of its descendants |
| Polyphyletic group | A group w/o a common ancestral species |
| Apomorphy | A specialized/derived character state on a phylo tree |
| Plesiomorphy | A primitive or ancestral trait on a phylo tree |
| Autapomorphy | A derived trait that is unique to 1 group on a phylo tree |
| Synapomorphy | A derived trait shared by 2+ groups on a phylo tree |
| Outgroup | A more distantly related group of organisms that serves as a reference group when determining evolutionary relationships of the ingroup |
| Limitations on phylogenetic trees | - Unless specified, branch length doesn't indicate the amount of time passed since the branch point - Taxa can change if evolved under different circumstances |
| Taxonomy | The grouping/classification of species based on subjective similarities and differences |
| Taxonomic classification system | A hierarchical model of groupings (taxa) that ranks organisms via their domain, kingdom, phylum, class, order, family, genus, and species - 2nd to phylogenetic trees |
| Cladistics | A method of determining phylogeny/hypothesizing relationships among organisms by analyzing their anatomical, physiological, behavioral, or genetic sequences |
| Principle of maximum parsimony | The state in which a phylogenetic tree features the fewest possible number of common ancestors, evolutionary steps, and branches between the organisms it features |
| Horizontal gene transfer (HGT) | The transfer of genetic material across normal reproductive barriers between distantly related organisms - 3 steps: transformation, transduction, conjugation (not gene transfer agents) - Prevalent in prokaryotes |
| The Endosymbiont Theory | - A cell which lives inside another cell w/ mutual benefit, making the "host" a supplemental organelle - Prokaryotes to eukaryotes evolution - Origin of mitochondria & chloroplast |
| Classic tree model vs. "Web of life" | |
| Ring of Life model |
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