The Theory of Evolution Flashcards
What is a mutation
-A random, spontaneous and permanent change to genetic material - they alter the structure of proteins that an organisms is able to produce.
- mutations are the only source of new alleles.
- Mutations can be advantageous, disadvantageous or neutral
What can increase the rate of mutation ?
Exposure to environmental factors - mutogenic agents - such as
-chemicals
-radiation
What is an adaptation ?
An adaptation is an inherited characteristic that makes an organism well suited to survival in its environment/niche
E.X.P different birds have different beak shapes which make then suitable for eating different foods.
What is evolution ?
-Variations within a population makes it possible for a population to evolve over time in response to changes in their environment.
what is a species
A group of organisms that can interbreed to produce fertile offspring.
what is variation?
Genetic differences in between members of the same species.
what does variation allow a population to do?
Allows a population to adapt over time in response to changing environmental conditions.
what can new alleles result in?
New alleles produced by mutations can result in plants and animals becoming better adapted to their environment.
what is an adaptation
Inherited characteristics that make an organism well suited to survive within its environment.
-these can be structural or behavioural
what are the types of behaviour
Innate behaviour - exists from birth or inherited
learned behaviour - gained from observation or experience
what is natural selection?
Occurs when selection pressures are present in an environment, only the best adapted individuals survive and reproduce.
Natural selection increases the frequency of favourable alleles that present a selective advantage within the population.
“survival of the fittest organism”
what are the stages of antibiotic resistance
1) One mutant bacteria arrives spontaneously within the population.
2) Mutant bacteria has a selective advantage against the antibiotic it is exposed to.
3) Mutant bacteria reproduces to make more resistant bacteria.
4) One of these mutant bacteria has a selective advantage against a second antibiotic that it is exposed to and survives.
5) Mutant bacteria reproduces to make more resistant bacteria
What is speciation
Speciation is when two ore more new species are formed from a common ancestor.
what are the stages of speciation
Stage 1 - Isolation
Original population is separated into two sub-populations by an isolation barrier.
Stage 2 - Mutations
Random mutations arise within each sub-population which increases variation between organisms.
Stage 3 - Natural Selection
Each sub-population is exposed to different selection pressures. Only organism with a selective advantage survive and reproduce.
Stage 4 - Speciation
The gene pool of each sub-population changes over many populations. The organisms become so genetically different they can no longer interbreed to produce fertile offspring - therefore they are no longer of the same species.
when does speciation occur
- It occurs after a part of a population becomes isolated by an isolation barrier; can be geographical, ecological or behavioural.
