9.3- GENETIC DIVERSITY AND ADAPTATION Flashcards
What is a gene?
section of DNA that codes for one polypeptide
What do all members of the same species have?
same genes
How do organisms of the same species differ?
in combinations of alleles
What is genetic diversity described as?
total number of different alleles in a population
What is a population?
group of individuals of same species that live in same place and can interbreed
What does a species consist of?
one, or more, populations
How can there be greater genetic diversity of a species?
the greater the number of different alleles that all members of species possess, greater the genetic diversity of that species
How is genetic diversity reduced?
when species has fewer different alleles
What is more likely, the greater the genetic diversity?
more likely that some individuals in population will survive an environmental change
Why is it that the greater the genetic diversity, the more likely that some individuals in population will survive an environmental change?
because of wider range of alleles + so wider range of characteristics
What does a wider range of alleles + so wider range of characteristics give?
greater probability that some individuals will possess characteristic that suits it to new environmental conditions
What is genetic diversity a factor for enabling?
enables natural selection to occur
Are all alleles of a population equally likely to be passed on to next generation?
no
Why are not all alleles of a population equally likely to be passed don to next generation?
only certain individuals reproductively successful + so pass on their alleles
What does differences between reproductive success of individuals affect?
allele frequency in populations
What will there be within any population of species? #1 (reproductive success and allele frequency)
gene pool containing wide variety of alleles
What can happen within the gene pool #2 (reproductive success and allele frequency)
random mutation of alleles within gene pool may result in new allele of gene which is most cases will be harmful
What can happen in certain environments with the new allele #3 (reproductive success and allele frequency)
new allele of gene might give its possessor advantage over other individuals in population
When an allele mutated and it gives its possessor advantage, what can that individual do? #4 (reproductive success and allele frequency)
these individuals will be better adapted + so more likely to survive in their competition with others
How are the individuals with the new allele better adapted? #5 (reproductive success and allele frequency)
more likely to obtain available resources + so grow more rapidly and live longer
so will have better chance of breeding successfully + producing more offspring
Who will pass on their alleles to the next generation? #6 (reproductive success and allele frequency)
only those individuals that reproduce successfully will pass on their alleles to next generation
So what is it that gave the parents the advantage in the competition of survival? #7 (reproductive success and allele frequency)
new allele that gave parents advantage in competition for survival that’s most likely to be passed on to next generation
What happens as the new individuals also have the new ‘advantageous’ allele? #8 (reproductive success and allele frequency)
in turn more likely to survive, + so reproduce successfully
What would happen over many generations with the new ‘advantageous’ allele? ‘#9 (reproductive success and allele frequency)
number of individuals with new, ‘advantageous’ allele will increase at expense of individuals with ‘less advantageous’ alleles
What happens overtime to the frequency of the new ‘advantageous’ allele? #10 (reproductive success and allele frequency)
frequency of new ‘advantageous’ allele in population increases while that of ‘non-advantageous’ ones decrease
What does what is ‘advantageous’ depend upon?
environmental conditions at any one time
