Natural Selection And Evolution Flashcards
What is natural selection?
Only the individuals best adapted to the environment will survive to pass on their advantageous alleles.
How are there different reproductive successes in a population?
Some individuals may have an allele making them more likely to survive and reproduce to pass on their genes with the beneficial allele.
What is evolution?
The gradual change in species overtime. It has lead to the huge diversity of living organisms on Earth.
What is an anatomical adaptation?
A structural/physical feature
What is a behavioural adaptation?
The way an animal behaves
What is a physiological adaptation?
The way it’s body works/processes in the body
Summarise the concept of the founder effect.
When a few individuals of a species colonise a new region and they only have a small fraction of the alleles of the total genetic diversity of the whole population. Therefore the new population that arises will have less genetic diversity.
What happens if a population has less genetic diversity?
They are less likely to be able to adapt to a change in conditions.
Genetic bottlenecks
A sudden fall in numbers in a population so there will be fewer different alleles so smaller diversity. As the species re-establishes, the new population will still only have the reduced number of alleles.
How can beneficial alleles be produced?
Random mutations
What is an adaptation?
Characteristic of an organism that makes them well suited to the environment so it has increased chance of survival.
What are the three types of natural selection?
Stabilising, directional, disruptive.
What is stabilising selection?
The most common phenotype is favoured
What is directional selection?
One extreme of the phenotype is favoured.
What is disruptive selection?
Where both phenotype extremes are favoured.
