Pack 10

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9.1

GENE MUTATION = CHANGE TO NUCLEOTIDE BASES OR CHANGE TO SEQUENCE OF BASES ON A GENE

CHROMOSOME MUTATION = CHANGE IN STRUCTURE OR NUMBER OF WHOLE CHROMOSOMES

MUTAGENIC AGENTS = CAUSE MUTATIONS E.G. CHEMICALS, RADIATION

SUBSTITUTION = SWAPPING SINGLE BASES, NOT ALL CHANGE SEQUENCE  OF AMINO ACIDS DUE TO DEGENERATE NATURE OF THE GENETIC CODE

DELETION/INSERTION = CAUSES FRAME SHIFT MUTATION SO CHANGES AMINO ACID SEQUENCE FROM THEN ON 

POLYPLOIDY = 3 OR MORE WHOLE SETS OF CHROMOSOMES RATHER THAN USUAL 2

NON-DISJUNCTION = INDIVIDUAL HOMOLOGOUS PAIRS FAIL TO SEPARATE IN MEIOSIS RESULTING IN AN EXTRA OR ONE LESS CHROMOSOME THAN USUAL

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9.2

MEIOSIS = PRODUCES 4 GENETICALLY DIFFERENT DAUGTER CELLS (HAPLIOD GAMETES), DIVISION 1 SEPARATES HOMOLOGOUS CHROMOSOMES, DIVISION 2 SEPARATES CHROMATIDS

INDEPENDENT SEGREGATION = HOMOLOGOUS PAIRS LINE UP RANDOMLY SO CONTENT OF DAUGHTER CELLS IS RANDOM

CROSSING OVER = CHROMATIDS BECOME TWISTED AND PORTIONS BREAK OFF AND RECOMBINE WITH CHROMATIDS OF PARTNER CHROMOSOME, NEW GENETIC COMBINATIONS OF ALLELES IS PRODUCED ALLOWING FOR GENETIC VARIATION

2n IS THE NUMBER OR HOMOLOGOUS CHROMOSOME PAIRS, E.G. WHERE 2n=4 IT GIVES 16 DIFFERENT COMBINATIONS

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9.3

GENETIC DIVERSITY = TOTAL NUMBER OF DIFFERENT ALLELES IN A POPULATION

POPULATION = GROUP OF INDIVIDUALS OF THE SAME SPECIES THAT LIVE IN THE SAME SPACE AND CAN INTERBREED

GENE POOL = NUMBER AND VARIETY IF ALLELES IN A POPULATION AT SPECIFIC TIME

ALLELE FREQUENCY = DIVIDE NO. TIMES ALLELE OF INTEREST IS OBSERVED BY THE TOTAL NO. COPIES OF ALL ALLELES IN A POPUALTION

NATURAL SELECTION = RANDOM MUTATION RESULTS IN NEW ALLELE, THOSE WITH NEW ALLELE BETTER ADAPTED AND MORE LIKELY TO SURVIVE UNDER THE SELECTION PRESSURES, THOSE THAT SURVIVE AND REPRODUCE PASS ON ADVANTAGEOUS ALLELE (REPRODUCTIVE SUCCESS), NEXT GENERATION MORE LIKELY TO SURVIVE AND REPRODUCE SO FREQUENCY OF ADVANTAGEOUS ALLELE INCREASES IN THE GENE POOL

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9.4

SELECTION = PROCESS BY WHICH ORGANISMS THAT ARE BETTER ADAPTED TO THE ENVIRONMENT SURVIVE AND BREED, THOSE NOT ADAPTED WILL NOT

DIRECTIONAL SELECTION = SELECTION FOR CHARACTERISTIC MAY FAVOUR INDIVIDUALS ONE DIRECTION AWAY FROM THE MEAN. E.G. ANTIBIOTIC RESISTANCE IN BACTERIA

STABILISING SELECTION = IN STABLE ENVIRONMENT INDIVIDUALS CLOSEST TO THE MEAN ARE FAVOURED SO MORE LIKELY TO SURVIVE AND REPRODUCE, ELIMINATES PHENOTYPES AT EXTREMES, E.G. HUMAN BIRTH WEIGHTS

NATURAL SELECTION = RESULTS IN SPECIES BETTER ADAPTED TO ENVIRONMENT, ADAPTATIONS MAY BE ANATOMICAL, PHYSIOLOGICAL OR BEHAVIOURAL 

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