3.6 Evolution Of Species Flashcards
What is a mutation?
Random, spontaneous change to the genetic material of an organism
What is the only source of new alleles?
Mutations
What can a mutation give to an organism?
An advantage or disadvantage for survival, or can be neutral (no effect on survival)
What can increase the rate of a mutation?
Radiation
Certain chemicals
What type of mutation is it if the organism is more likely to survive?
Advantageous
What can new alleles produced through mutation do to a plant or animal?
make a plant or animal better adapted
What is an adaption?
An inherited characteristic which makes an organism well suited to its environment
When does evolution occur?
When a species becomes better adapted to an environment over time
When environmental conditions change
What are the factors which determine which organisms survive called?
Selected pressures
What causes natural selection?
More offspring than can survive in an environment
What is natural selection?
Survival of the fittest
What does selective advantage refer to?
Individuals who are best adapted to the environment, who will be able to survive
What happens when the well adapted individuals reach adulthood and reproduce?
Pass on their favourable alleles
What will happen to the population when the number of individuals with favourable alleles increase in frequency?
Become better adapted to the environment
What is speciation?
Production of new species, involves mutations and natural selections
When does speculation occur?
When part of the population is isolated by an isolation barrier
What types of isolation bars are there?
Geographical (river)
Ecological (diff ph levels)
Behavioural (active at diff times)
