Biology Exam 4
Terms
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- polygenic traits
- trait controlled by two or more genes
- green revolution
- the development of highly preoductive crop strains and use of modern agricultural techniques to increase yields of food crops
- agriculture
- the practice of farming
- ozone layer
- atmosphere layer in which ozone gas is relatively concentrated
- ecosystem diversity
- variety of habitats, living communites, and ecological processes in the living world
- immigration
- movement of individuals into an area occupied by an existing population
- aquaculture
- the raising of aquatic organisms for human consumption
- population density
- number of individuals per unit of area
- tetrad
- structure containing 4 chromatids that forms during meiosis
- carrying capacity
- largest number of individuals of a population that a given environmant can support
- desertification
- in areas with dry climates , a process cause by a combination of poor farming practices, overgrazing, and drought that turns productive land into desert
- gene map
- diagram showing the relative locations of each known gene on a perticular chromosome
- sustainable development
- using natural resources at a rate that does not deplete them
- deforestation
- destruction of forests
- genotype
- genetic make up of and organism
- haploid
- term used to refer to a cell that contains only a single set of chromosomes and therefore only a single set of genes
- limiting factor
- factor that cause the growth of a population to decrease
- meiosis
- process by which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell
- exponential growth
- growth patterns in which the individuals in a population reproduce at a constant rate
- codominance
- situation in which both alleles of a gene contribute to the phenotype of the organism
- conservation
- wise management of natural resources including the preservation of habitats and wildlife
- species diversity
- number of different species in the biosphere
- incomplete dominance
- situation in which one allele is not completely dominant over another
- logistic growth
- growth pattern in which a populations growth rate slows or stops following a period of exponential growth
- crossing-over
- process in which hohmlogous chromosomes exchange portions of their chromatids during meiosis
- genetic diversity
- sum total of all the different forms of genetic information carried by all organisms living on Earth today
- independent assortment
- independent segregation of genes during the formataion of gametes
- soil erosion
- weaing away of surface soil by water and wind
- habitat fragmentation
- splitting of ecosystems into small fragments
- emigration
- movement of individuals out of an area
- acid rain
- rain containg nitric and sulfuric acids
- demographic transition
- change in a population from high birth and death rates to low birth and death rates
- monoculture
- farming strategy in which large fields and planted with a single crop, year-after-year
- multiple alleles
- three or more alleles of the same gene
- extinction
- disappearance of a species from all parts of its geographical range
- nonrenewable resource
- resource that cannot be replenished by natural processes
- renewable resource
- resources that can regenerate quickly and that is replacable
- homologous
- term used to refer to chromosomes that each have a corresponding chromosome from the opposite-sex parent
- diploid
- term used to refer to a cell that contains both sets of homologous chromosomes
- smog
- mixture of chemicals that occurs as a gray-brown haze in the atmosphere