3.4.4 Genetic Diversity and Adaptation Flashcards
What are the steps of variation on a larger scale?
There is an initial gene pool
A random mutation occurs- mostly harmful
If it is advantageous, the organism is better adapted and more likely to live and breed
The offspring is also likely to have a new allele
Over time the allele frequency increases
How do the conditions an organism lives in affect a mutation?
Happens no matter what conditions it lives in
The benefits of a mutation are determined by the environment
What is a species?
A group of organisms that can interbreed to produce fertile offspring
What is a population?
A group of organisms of the same species living in the same area
What is directional selection?
When the normal distribution shifts to the left or right due to an environmental charge (selection pressure) or an advantageous mutation occurs
Graph shifts in favour of the advantageous allele
What is stabilising selection?
Environmental conditions are stable
Individuals with phenotypes closest to the mean are favoured
These individuals are more likely to breed
It tends to eliminate phenotypes at the extremes
Graph: peak is higher and spread is narrower
How does a mutation affect a protein receptor?
Change in DNA nucleotide sequence
Change in amino acid sequence
Alters position of hydrogen/ionic/disulfide bonds
Change in tertiary structure of receptor
