Topic 4- Natural selection Flashcards
What can produce new alles?
Random mutations
Under certain environmental conditions, individuals with certain alleles will have an 1.______ chance of survival and reproduction
1.increased
What can natural selection do to the frequency of alleles over time?
Change
While many mutations are harmful/neutral, under certain conditions the alleles may….
- Benefit their possesor\
-Leading to an increased chance of survival
-Increased chance of reproductive success
-Advantageous allele is passed on through generations
-Allele frequency increases over time
What increases the likelihood that certain individuals with specific alleles survive to reproductive age, enabling them to pass on their alleles to their offspring?
Selection pressures (caused by the environment)
What are the other 3 factors or processes that can affect allele frequencies in a population?
-The founder effect
-Genetic drift
-The bottleneck effect
What is the founder effect?
when only a small number of individuals from a large parent population start a new population
What is the effect of the founder effect?
- only some of the total alleles from the parent population will be present
-not all of the gene pool is present
Which alleles end up in the new founding population is completely due to?
Chance
What is genetic drift?
a gradual change in allele frequencies in a small population due to chance and not natural selection
What is a genetic bottleneck?
hen a previously large population suffers a dramatic fall in numbers
What effect does the bottleneck effect have?
-reduces the genetic diversity in the population as alleles are lost
-surviving individuals end up breeding and reproducing with close relatives
M
V
A
S
R
I
Mutation
Variation
Adaptation
Survival
Reproductive sucess
Increase in allele frequency
