Term
| State two costs of sexual reproduction. |
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Definition
| males unabe to produce offspring; only half the genome of each parent passed onto offrpsing |
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Term
| Explain the disadvantage of only half the genome of parents being passed on to offspring in sexual reproduction. |
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Definition
| successful parental genomes will be distrupted |
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Term
| Explain why the beneifts of sexual selection outweigh the costs. |
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Definition
| the increased genetic variation in the population is a major advantage |
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Term
| What is the benefit of sexual reproduction? |
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Definition
| geneic variation is introduced which may help species survive in changing conditions. |
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Term
| What is the Red Queen Hypothesis? |
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Definition
| idea that species must constantly adapt and evolve to survive when co-existing with ever-evolving species |
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Term
| How does the Red Queen hypothesis explain the persistence of sexual reproduction? |
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Definition
| sexual reproduction leads to greater genetic variation, which leads to more opportunities for evolution |
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Term
| Which type of co-evolutionary interaction may select for sexual reproduction? |
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Definition
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Term
| What is the advantage to a host of reproducing sexually? |
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Definition
| genetic variability in their offspring reduces the |
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Term
| State two benefits of asexual reproduction. |
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Definition
| whole genome is passed from parent to offspring; only one parent needed to establish a colony |
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Term
| In what conditions is it an advantage to maintain the parental genome (as in asexual reproduction) ? |
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Definition
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Term
| Name the form of asexual reproduction in eukaryotic plants (includes runners, tibers, bulbs). |
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Definition
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Term
| Name the form of asexual reproduction in animals that lack fertilisation and lower plants. |
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Definition
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Term
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Definition
| reproduction from a female gamete without fertilisation |
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Term
| In which conditions is parthenogenesis more common? |
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Definition
| Cooler climates where parasitism is less common or regions of low parasite denisty |
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Term
| What is the advantage of the benefits of asexual reproduction? |
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Definition
| offspring produced more often and in larger numbers |
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Term
| What disadvantage do asexually reproducing populations have? |
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Definition
| populations not able to adapt easily to changes in their environment |
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Term
| What is the only source of variation in organisms that use asexual reproduction? |
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Definition
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Term
| What can happen as a result of advantageous mutations in a population? |
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Definition
| natural selection and evolution |
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Term
| What is horizontal gene transfer? |
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Definition
| Passing of genetic material within a generation |
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Term
| What is the advantage of horizontal gene transfer? |
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Definition
| faster evolutionary change (than organisms that only use vertical transefer) |
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Term
| Horizontal gene transfer is most common in which domain of organisms? |
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Definition
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Term
| Which cell structure is used in the transfer of genetic material within a generation? |
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Definition
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Term
| Name two types of cell that contain plamids? |
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Definition
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Term
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Definition
| the division of the nucleus that results in the formation of halpid gametes from diploid gametocytes |
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Term
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Definition
| A diploid cell able to make gametes (a gamete mother cell) |
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Term
| Name the three features that match in homologous chromosomes. |
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Definition
| same size, same posistion of the centromere, same gene sequence and loci |
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Term
| What is the locus of a gene? |
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Definition
| the position of the gene on a chromosome |
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Term
| What is the difference between diploid and haploid cells? |
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Definition
| diploid have two copies of each chromosome (2 sets) , haploid has one copy of each chromosome (1 set) |
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Term
| How many divisions are there in meiosis? |
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Definition
|
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Term
| Describe the appearance of chromosomes after DNA replication |
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Definition
| each chromosome is made of two genetically chromatids attached at the centromere |
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Term
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Definition
| points of contact between the non-sister chromatids of a homologous pair |
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Term
| What happens at chiasmata? |
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Definition
| crossing over = excahnge of sections of DNA between non-sister chromosomes |
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Term
| What are non-sister chromatids? |
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Definition
| the chromatids that are beside each other when homologous chromosomes pair up - one from each chromosome |
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Term
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Definition
| gene that are located on the same chromosome |
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Term
| What effect can crossing over have on linked genes? |
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Definition
| new combinations of alleles of these genes |
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Term
| What is the importance of crossing over? |
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Definition
| source of variation as it produces genetically different recombinant chromosomes |
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Term
| What two roles do spindle fibres have in meiosis 1? |
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Definition
| attach to homologous pairs to line them up on the equator, then separate the homologous pairs |
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Term
| What is independent assortment? |
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Definition
| the random alignment of maternal and paternal chromosomes on the equator in meiosis 1 |
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Term
| What are the two sources of variation in gametes that result from meiosis? |
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Definition
| crossing over and independent assortment |
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Term
| What is the final stage of meiosis 1? |
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Definition
| cytokinesis forming two daughter cells |
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Term
| What happens in meiosis 2? |
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Definition
| each of the two cells formed in meiosis 1 undergo another division to separate the sister chromatids |
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Term
| How many cells are produced by meiosis? |
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Definition
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Term
| What determines the sex of birds, mammals and some insects? |
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Definition
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Term
| What is the purpose SRY gene on the Y chromosome in most mammals? |
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Definition
| Determines development of male characteristics |
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Term
| What is meant by heterogametic ? |
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Definition
| having XY sex chromosomes |
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Term
| What is meant by homogametic? |
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Definition
| having XX sex chromosomes |
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Term
| What is the impact of having XY sex chromosomes? |
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Definition
| males lack most of corresponding homologous alleles on the shorter Y chromosome |
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Term
| What is the genotype of an affected male in sex linked recseeive inheritance? |
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Definition
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Term
| What is the genotype of a carrier female in sex linked recseeive inheritance? |
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Definition
|
|
Term
| What is X chromosome inactivation? |
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Definition
| the random inactivation of one of the two X chromosomes in each cell of homogametic females in the early stage of development |
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Term
| Why is X chromosome inactivation important? |
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Definition
| prevents the cells getting a (potentially harmful) double dose of gene products |
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Term
| What is the impact on carriers of x chromosome inactivation? |
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Definition
| less likely to be affcted by any deleterious (disadvantageous) mutations on the X chromosomes. |
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Term
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Definition
| genes which are on the section of the X chromosome where there is no corresponding Y chromosome |
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Term
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Definition
| Organism with functioning male and female reproductive organs |
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Term
| What kind of gametes do hermaphrodites produce? |
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Definition
|
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Term
| How do hermaphrodites reproduce? |
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Definition
| sexually by excghanging gametes with a partner |
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Term
| What is the advantage of being hermaphrodite? |
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Definition
| in organisms that rarely encounter another member of the species when they do meet a partner there is no need for it to be the opposite sex |
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Term
| What factors determine sex in species that are not birds, mammals or some insects? |
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Definition
| environmental factors e.g. temperature |
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Term
| Name three biotic factors that can chnage the sex within individuals. |
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Definition
| Parasitism, competition and size. |
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Term
| Name a biotic factor that can adjust the sex ratio of offspring. |
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Definition
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