Buscar
Estás en modo de exploración. debe iniciar sesión para usar MEMORY

   Inicia sesión para empezar

level: 9.3 Genetic diversity and adaption

Questions and Answers List

level questions: 9.3 Genetic diversity and adaption

QuestionAnswer
Genetic diversity meaning- The no. of different alleles of genes in a species or population - Allows natural selection to occur
What increases genetic diversity- Mutations in DNA, forming new alleles - Different alleles being introduced into a population from another migrating population + reproduce, called gene flow
Genetic bottleneck- An event that causes a big reduction in a population - Reduces no. of different alleles in the gene pool, reduces genetic diversity - Survivors reproduce, large pop. created from new individuals
The founder effect- Type of genetic bottleneck - Describes what happens when just a few organisms from a population starts a new colony - Where there is a small no. of alleles in gene pool - Can be caused by geographical separation
Frequency of alleles in new colony- Might be very different to frequency of alleles in original population - So higher chance of genetic disease
Key factors of evolution- Adaptation - Selection
Reproductive success meaning- No. of offspring an individual produces
Natural selection meaning- Process where organisms that are better adapted to an environment will survive and reproduce - There is differential reproductive success between the organisms with different alleles of the same gene
Natural selection process (1)- Random mutation produces new alleles of a gene
Natural selection process (2)- Many mutations are harmful or neutral but, under certain environmental conditions - New alleles may benefit their possessor - Leading to an increased chance of survival and increased reproductive success
Natural selection process (3) (ad-van-tae-jus)- The advantageous allele is passed onto the next generation
Natural selection process (4)- As a result, over several generations, the new allele will increase in frequency in the population
+ Natural selection process (1)- All offspring produce more offspring than required - Population size of species remain relatively stable
+ Natural selection process (2)- There is a struggle for existence - The offspring will have a gene pool - a variety of alleles
+ Natural selection process (3)- The fittest offspring (that have the most favourable alleles) are more likely to survive + reproduce
+ Natural selection process (4)- The offspring in turn are more likely to inherit the favourable alleles (and thus survive and reproduce) - Over time the frequency of advantageous alleles increases - Leads to evolution of new species