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CH.20-55
Biology study guide
| Question | Answer |
|---|---|
| Mutations | Ultimate source of genetic variation, occur 1 per 100,000 cell divisions |
| Gene Flow | Movement of alleles from one population to another. Exchange genetic material |
| Assortive Mating | Non-random mating where pheotypically similar individuals mate and produce homozygotes |
| dissassortive Mating | Non-random mating where phenotypically different individuals mate to produce heterozygotes |
| Genetic Drift | Drastic change by change |
| Founder Effect | (genetic drift)- 1 or few individuals of a population become the "founder" of a new isolated population. Some alleles are lost. |
| Bottle Neck Effect | Population is drastically reduced in size. Loss of genetic variability. |
| Artificial Selection | Breeder selects desired characteristics |
| Natural selection | environmental conditions determine which individuals produce offspring ( learn the conditions required for natural selection to occur) |
| Sexual Selection | preferential mating |
| Fitness | is the reproductive success, leading to the most fit making greatest number of offspring |
| What affects fitness of individual? | survival, mating success, number of surviving offspring |
| Oscillating Selection | favorite phenotype changes as environment changes. Maintains genetic variation |
| Heterozygote Advantage | Favors individuals with copies of both alleles. Maintains both alleles in the population. |
| Requirements for survival of fittest individuals | 1. successful survival of individual within population. 2. Successful sexual selection of the individual within the population for the puropose of reproduction. 3. successful production of offspring |
| Relaxed slective pressures | caused optimal environmental conditions. decreases variation. |
| directional selective pressures | caused by changing environmental conditions. Selection against an extreme. |
| Disruptive selective pressures | caused by extreme environmental conditions. selection against the mean, causes different extremes to be successful. |
| Population Dynamics | How a population changes through time |
| Demography | Statistical study of populations |
| Sexratio | number of males to females |
| Generation time | Average intervals between birth of individuals and birth of offspring |
| Cohorts | groups of individuals of same age |
| fecundity | birth rate |
| Mortality | Death rate |
| Life History | complete life cycle of an organism |
| Cost of Reproduction | reduction in future reproductive potential resulting from current reproductive efferts |
| Low costs of reproduction | Resources are plentiful or mortality rates are high, tends to produce as many offspring as possible |
| High costs of reproduction | Minimize reproduction to maximize survival reates |
| Crude Birth rate | Number of births per year per 1000 population. ( determined by {total births/mid-year population} X 1000 |
| Crude Death rate | Number of deaths per year per 1000 population. ( determined by { total births/mid-year population} X 1000 |
| Rate of Natural Increase | Crude Birth Rate - Crude Death Rate |
| percent annual Growth | rate of natural increase/10 |
| Doubling time | 70 / percent annual growth |
| Stable populations | No overall increase |
| Stationary populations | no change in subgroups |
| Type 1 survivorship | Mortality after reproductive year. Slowly reproduce. ex: humans, and get to take care of young |
| Type 2 survivorship | Uniform mortality, ex: hydra |
| Type 3 survivorship | High mortality early, reproduce rapidly. offspring more likely to die so have a large number of them |
| Biotic potential | number of offspring produces under ideal conditions |
| Intrinstic Rate of Growth | Speed of growth, "r" = rate of population increase |
| Controlling factors | 1. age of female when she begins to reproduce, b. Number of offspring produced per cycle, c. number of reproductive years |
| Population Growth | (Natality + Immigration)-(Mortality + emigration) |
| Arithmetic Growth | add same number each time period, population increases evenly if rate is constant |
| Exponential Gorwth | look up in notes |
| Carrying Capacity | K, Maximum population a habitat will support without being degraded, and is not constant because environment and resources change |
| Environmental resistance | as N(population) increases, so does resistance |
| S-shaped (signoid) growth curve | logistic growth, levels off when it reaches a certain point |
| Density Dependent Resistance | Limiting facto that affects large populations, as population increases, these factors Increase their effect on size of population |
| Low Breeding Density Populations | Critical number = minimum population needed to survive; unlikely that mating pairs will find each other |
| Density Independent Resistance | Limiting factor that as population increases, these factors do not increase or decrease. still affect size of population |
| r- strategists | Large number of offspring that mature rapidly, operate below carrying capacity, reproduce when young, and have short lifespans. |
| K- strategists | small numbers of offspring that mature slow, lot of protection for offspring, long lifespan, delayed reproduction |
| Intra-specific competition | competition within same species, more fierce |
| Scramble competition | Intra-specific competition, occurs within creatures with decreased intelligence, no rules everything is by change, and no one obtains adequate resources |
| Contests | Increased intelligence life forms, dominant ones obtain resources |
| types of contests | Territoriality, Dominant heirarchy, Courtship rituals, and Metamorphosis |
| Inter-specific competition | competitive exculsion factor, occurs between different species |
| competitive exclusion | no two organisims can occupy the same place at the same time |
Created by:
sonic7emeral
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