Welcome to your Edexcel A2 Biology 2 1. A situation where Hardy-Weinburg calculations does not apply. No natural selection Non random mating No immigration or emigration Population must be very large.2. Select the incorrect sentence out of the following. A quadrat is usually a line made of wire. Quadrats may be used for slow-moving animals such as slug and snails. A quadrat should be placed randomly so that a representative sample is taken. The number of organisms of each species can be observed and recorded at regular intervals along the transect.3. The mark-release-recapture method of sampling is used among __________. Motile and non motile organisms Motile organisms Non motile organisms Only deers4. Unique species of plants and animals in the Hawaiian and Galapagos islands is an example of ____________. Sympatric speciation Extinction Allopatric speciation Natural selection5. What is the possible genotype of an eggplant with brown stems? aa & AA AA & Aa Aa & aa AA & a6. What does q2 represent in the Hardy-Weinburg equation p2+2pq+q2=1? Percentage of homozygous recessive individuals Frequency of the recessive allele in the population. Frequency of the dominant allele in the population. Percentage of heterozygous individuals.7. An ecological barrier which could cause sympatric speciation. Different timings Mating dances Locomotion Breeding areas8. A brown stemmed eggplant has 2 genotypes. In order to determine its exact genotype, it could be crossed with a ___________. Brown stemmed eggplant Green stemmed eggplant An unmatured eggplant A matured eggplant9. Answer the following 4 questions by reading the given description. In an eggplant that has one allele for brown stems and one allele for green stems, the stems are exactly the same shade of brown as in a plant that has two alleles for brown stems. The allele for brown stems is dominant, and the allele for green stems is recessive. What is the genotype of eggplants with green stems? Aa a AA aa10. A behavioural barrier which could cause sympatric speciation. Salinity pH Different habitats Mating dances11. Industrial melanism is an example of ___________. Stabilising selection Sexual selection Directional selection Disruptive selection12. Select the incorrect statement regarding allopatric speciation. Species of plants and animals in Galapagos islands is an example of allopatric speciation. Very small or immobile organisms can be isolated by smaller-scale barriers. Species of plants and animals in Hawaiian islands is not an example of allopatric speciation. Allopatric speciation is when new species arise due to isolation of a population by geographical barriers.13. Select the mechanisms which contribute towards changing the pool of genes. a) Natural selection b) Gene transfer c) Genetic drift d) Speciation b & c only a, b & c a &b only All14. The primary source of genetic variation within a population of a species. Sexual reproduction Meiosis Environmental factors Mutation15. Select the incorrect statement regarding mutations. Changes in the genome are called mutations. Single gene mutations do not occur. Mutations can result in either no protein or an altered protein being expressed. Some mutations can affect the structure of one or more chromosomes.16. Clutch size in birds is an example of ___________. Sexual selection Disruptive selection Directional selection Stabilising selection17. What is the meaning of 'Allopatric'? In different places In atmosphere In different seas In the same place18. Which of the following geographical barriers can lead towards allopatric speciation? a) Rivers b) Mountain ranges c) Continental drift d) Small pond a, c & d b & d b & c only a, b & c19. Which selection favours both extremes of continuous variation? Stabilising selection Directional selection Disruptive selection Artificial selection20. A process which does not facilitate natural selection. Artificial breeding Competition Predation Disease21. Within a population of rabbits, the colour black (B) is dominant over the colour white (b). And, 30% of all rabbits are white. What is the percentage of heterozygous rabbits in the population? 42% 36% 50% 46%22. Select the correct statement about sympatric speciation. Behavioural barriers do not contribute towards sympatric speciation. Ecological barriers do not contribute towards sympatric speciation. Sympatric speciation occurs due to geographical barriers. The commonest way in which sympatric speciation can occur is through polyploidy.23. Change in allele frequencies due to a new environmental factor or a new allele. Stabilising selection Directional selection Disruptive selection Natural selection24. The above cross is an example of a _________. Dihybrid cross Test cross Co dominance Monohybrid crossTime is Up!