Welcome to your CIE A2 Selection and evolution Which of the following gives rise to genetic variation in a population? a) crossing over and independant assortment in meiosis b) different environmental conditions c) random mating and fertilisation d) mutation All of the above a, c & d a, b & c b, c & dIn 2011, which animal was declared extinct by the IUCN? African southern white rhino Bengal tiger Western black rhino of Africa PandaThe International Union for Conservation of Nature (IUCN) annually publishes a ________ of threatened species. Black List Notice Red List Yellow ListA species of finch living on an isolated island shows variation in beak size. Birds with larger beaks can eat larger seeds. After a period of drought on the island, large seeds were more plentiful than small seeds and the average size of the finches' beaks increased. What explains this increase in size of beak? Artificial selection acting against finches with small beaks. Stabilising selection acting against finches with the smallest and largest beaks. Directional selection acting against finches with small beaks. Increased rate of mutation resulting in finches with larger beaks.In Siamese cats, dark hair develops where the skin is at relatively low temperature. This is an example of: Genetic mutation Effects on the phenotype due to random mating between organisms within a species. Environmental effects on the phenotype Independant assortment of chromosomesSelect the incorrect statement regarding antibiotics. The selection pressure on bacteria remains unaffected by the use of antibiotics. Most antibiotics are produced by fungi. The first antibiotic to be discovered was penicillin. Penicillin stops cell wall formation in bacteria.An example of continuous variation. Height Blood group Eye colour Gender (male/female)Select the correct statement about sympatric speciation. The commonest way in which sympatric speciation can occur is through polyploidy. Ecological barriers do not contribute towards sympatric speciation. Behavioural barriers do not contribute towards sympatric speciation. Sympatric speciation occurs due to geographical barriers.The type of selection that occurs when conditions favour both extremes of a population. Disruptive selection Stabilising selection Directional selection Artificial selectionA prezygotic isolating mechanism. Non-viable offspring (offspring that die soon) Viable, but sterile offspring Animals being physically unable to mate. Failure of cell division in the zygote.Which is not an advantage of having shorter stems in wheat plants? Less able to compete against other plants for light. Less susceptible to being knocked flat by heavy rains. Easier to harvest Higher yieldsTime is Up!