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Details Title: Exam 2 Description: BIO106 - Nickell Total Flash Cards: 41 Created: 02/08/2005 14:12:22	To study from this set of flash cards, or to create your own your own study flash cards, register HERE. If you are already a registered user, CLICK HERE.
Cards Term Darwin- Theory, Finches, Research (where) Definition - HMS Beagle - Galapagos Islands - Theory of Uniformity – things change in slow, gradual, uniform, and repetitive ways Term Populations- characteristics Definition - group of individuals of the same species living together - have similar morphological, physiological, and behavioral traits Term Polymorphism Definition - many different possibilities for characteristics Term Gene Pool Definition - all the genes of an entire population - genes can be shared by all members of population Term Alleles/ new alleles Definition - genes that code for different versions of the same trait - *Genetic mutation - Crossing over a meiosis - Independent assortment at meiosis - Fertilization - *Change in chromosome number or structure Term Allele frequency Definition - the number of different alleles in a population Term Genetic equilibrium Definition - allele frequencies remain the same at a given locus from one generation to the next (population not evolving) Term Microevolution Definition - The small scale changes in allele frequency brought about by mutation, natural selection, gene flow, and genetic drift Term Mutation rate Definition - the probability of a gene mutating during or between DNA replication (different for every gene) Term Mutations Definition - lethal - neutral Term Natural selection Definition - environmental influences lead to natural selection - Darwin’s observations - Fitness – an increase in adaptation to the environment - Driven by: o Resources o Habitat o Predators Term Directional selection-example Definition - a range of alleles that give rise to a range of variation in phenotype tend to shift in a consistent direction - Example: Peppered moth blending into the trees; changes with pollution Term Negative effects of natural selection Definition - pesticide resistance - antibiotic resistance Term Stabilizing selection Definition - Intermediate forms of a trait in a population are favored and extreme alleles are lost - Average is better - Example: gull flies Term Disruptive selection Definition - extreme traits are favored over intermediate ones Term Sexual selection Definition - traits are selected for because they off an advantage in reproduction simply because they are attractive to the opposite sex - females act as selective agents Term Male coloration Definition - tend to be brightly colored and have unique features Term Balanced polymorphism Definition - two or more alleles coding for a given trait that are in the population - sickle cell anemia - malaria acts as a selective force in some African populations - heterozygous individuals are more likely to survive malaria Term Gene flow: emigration and immigration Definition - emigration: move out of an area - immigration: moving into an area - Example: tree species Term Genetic drift Definition - a random change in allele frequency brought about by chance alone Term Fixation Definition - only one allele at a specific site; no genetic diversity - bad Term Bottleneck Definition - severe reduction in population size due to severe selection pressure or a calamity Term Founder effect Definition - reduction of allele frequency after a few individuals start a new population Term Speciation- “species” Definition - Latin for “kind” Term Biological species concept Definition - a species is a one or more populations of individuals that are interbreeding under natural conditions, producing fertile offspring, and are isolated from other such populations Term Genetic divergence Definition - gradual accumulation of differences in gene pools of populations after isolation Term Mechanisms of reproductive isolation Definition - any heritable feature of body form, functioning or behavior that prevents interbreeding between species Term Behavioral isolation Definition - courtship, secret handshake - birds mostly Term Temporal isolation Definition - Breeding takes place at different times (Cicadas) Term Mechanical isolation Definition - physical adaptations that limit reproduction - flower petals and wasps Term Ecological isolation Definition - two species that can cross-breed do not occupy the same area Term Gametic mortality Definition - if cross-breeding occurs the gamete will die or yield hybrids - Example: horse + donkeys = mules Term Allopatric speciation Definition - Physical barriers separate populations, and prevent gene flow between the two populations, and favors divergences that end in speciation - Example: blue-headed wrasse and the Cortez rainbow wrasse - Archipelagos- an island chain some distance away from the mainland (Hawaii) - Hawaiian honey creepers - Founder species spreads out and develops adaptations to new environments Term Sympatric speciation Definition - New species developing within the range of another species - Cichlids in Lake Tanganyika, Lake Barombi Mbo Term Parapatric speciation Definition - Neighboring populations become distinct species while maintaining contact along a common border - Hybrid zone - Baltimore Oriole and Bullock’s Oriole Term Cladogenesis Definition - genetic lineage splits and isolates populations - big and sudden changes Term Anagenesis Definition - allele frequency change in morphology in line of descendants - small and gradual changes Term Evolutionary trees Definition - slight angle branches - horizontal branches Term Rates of change Definition - Gradual model of speciation: species emerged from many small morphological changes over a long period of time - Punctuation model of speciation: most changes of morphology are compressed into a brief period Term Adaptive radiation Definition - A burst of divergences from a single lineage that give rise to many new species - Gives rise to a new species - *Each species adapts to a new habitat or novel resource - Example: rise of the mammals after the dinosaurs Term Extinction- human causes, major cause, survivors Definition - Extinctions allow for adaptive radiation (resources, niches are unfilled) - Extinction rates higher than ever today (human impacts: habitat loss) - human causes o urban sprawl o over-harvesting o * habitat loss o global warming o chemical impacts - survivors o some is luck o widely distributed species tend to survive