Natural Selection Flashcards
What is natural selection?
when the allele codes for a characteristic that increases the chance of an organism surving and the frequency within the population
What is directional selection?
where individuals with alleles for characteristics of an extreme type are more likely to survive and reproduce which could be in result to environmental changes - modal trait changes
What is stabilising selection?
- where individuals with alleles for characteristics towards the middle of the rsnge sre more likely to survive and reproduce
- occurs when the environment is not changing and it reduces the range of possible characteristics
- the modal trait has the selective advanatge and remains the same
- the standard deviation decreases as individuals with the extreme trait decreases
What is the process of natural selection?
1.) there is differential reproductive success in a population (not all individuals are as likely to reproduce as eachother) - individuals that hace an allele that increases their chances of survival are more likely to survive, reproduce and pass on their genes, than individuals with less advantageous alleles
2.) This means that a greater proportion of the next generation inherits the beneficial allele
3.) they are more likely to survive, reproduce and pass on their genes
4.) the frequency of the beneficial allele in the populatin increases from one generation to the next
5.) over generations this leads to evolution as the advantageous alleles become more common
What is evolution?
the gradual change in species over time which leads to diversity
