Selective breeding (also called artificial selection ) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics ) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together. Domesticated animals are known as breeds, normally bred by a professional breeder, while domesticated plants are known as varieties , cultigens, or cultivars. Two purebred animals of different breeds produce a crossbreed . Flowers, vegetables and fruit-trees may be bred by amateurs and commercial or non-commercial professionals: major crops are usually the provenance of the professionals.

Which of the following scenarios is an example of the bottleneck effect? answers a in south africa, much of the afrikaner population is descended from a small number of dutch colonists. in this population, this is an unusually high frequency of pseudoxanthoma elasticum (pxe), an elastic tissue disorder. b four white-tailed deer are introduced to a park in finland. thirty years after their introduction scientists compare the genes in the population and find that there is no variation. c during the industrial revolution, london's air became filled with soot. as a result, birds started eating more of the lighter moths because they were easier to spot than their darker counterparts. over time, the moth population changed so that there were more darker moths than lighter ones. d 10% of the population of american alligators in an area have the recessive trait albinism. a massive flood results in the death of 80% of the population. of the remaining population, 60% have the recessive trait of albinism.

2. cheryl hears a new song on the radio every day during the week on her commute to work. surprisingly, when the song comes on at a party on saturday night, she knows most of the words without trying. describe the three ways that we use cognition to learn without reinforcement. which type of cognitive learning without reinforcement best explains how cheryl knew the song lyrics? explain your answer.

Climate like that in the sahara desert have the fastest rates of weathering