Natural Selection Flashcards
Model answer- natural selection
Mutation leads to variation in a species by developing a new allele
The new allele provides an advantage (give example)
Organisms with the new allele can survive and reproduce
Advantageous allele is passed onto the offspring
The advantageous allele increases in frequency in the population
What is artificial selection?
Selection is forced by something else. The process is the same but selection is caused by humans
What is selection pressure?
An environmental force which can alter the frequency of alleles in a population
Give examples of selection pressure
Temp changes
Predators
Diseases
PH changes
Colour changes in environment
What causes variation?
Mutations
Meiosis
Random fertilisation
Genetics
Describe how farming cattle as a source of milk could have led to an increase in LP?
LP produced due to mutation
Milk provides nutrients
Individuals with LP more likely to survive and reproduce
Frequency of allele increases in offspring
What is directional selection?
If an environment changes the selection pressure will be exerted on a particular portion of the population. There is a shift to a new advantageous allele
What is stabilising selection?
When both ends of the population are selected against
What is disruptive selection?
Selection pressure is on the mean of the population. The general population is selected against. Population separates sometimes into 2 new species
