Isolation + Speciation Flashcards
What is speciation?
Speciation is the process that results in the creation of new species. An evolution of new species from existing ones
What is isolation?
Isolation is when two populations of the same species can no longer breed together
When does speciation occur?
Speciation occurs when the original population of the same species becomes reproductively isolated
What does reproductive isolation result in?
Reproductive isolation results in the accumulation of differences within each species’ gene pool, this is because over many generations they will have slight differences in their allele frequency and may accumulate different mutations
What does reproductive isolation lead to?
Reproductive isolation leads to two populations being very so genetically different, that they are unable to interbreed and make fertile offspring, therefore they will be classes as two different species
What is a species?
A species is a group of individuals that have a common ancestry, therefore sharing the same genes but different alleles making them capable of breeding with one another to produce fertile offspring
What is adaptive radiation?
Adaptive radiation is when the different phenotypes each produce different combinations of alleles that are made subject to selection pressures that lead to each populationmbecoking adapted to its local environment
What events occur that lead to adaptive radiation?
A population that has been separated from their original population will undergo different mutations to eventually become genetically different from the original population.
Each population will experience different selection pressures because their environments will be slightly different
Natural selection will then lead to changes in the allelic frequencies of each population.
What does adaptive radiation result in?
Adaptive radiation results in changes to the allele frequencies of each population - each population evolving
What are the two forms of speciation?
Allopatric speciation, geographic, and Sympatric speciation, changes in reproductive mechanisms
What is allopatric speciation?
Speciation that occurs when two populations become geographically separate, leading to reproductive isolation
What can geographical separation be the result of? What is an example of this cause?
Geographical separation can be the result of any physical barrier preventing interbreeding. For example, oceans, rivers, mountain ranges and deserts
Outline the process of allopatric speciation (3pts)
The two populations will become separated by some form of geographical barrier and will continue to accumulate different beneficial mutations to help their survival in their environments.
Due to the accumulation of DNA differences, the two populations become very genetically different that they are unable to interbreed to create fertile offspring.
Therefore becoming classed as two different species
What is sympatric speciation?
This is a type of speciation that occurs within a population in the same area due to the differences in their behaviour leading to them becoming reproductively separated
What can cause sympatric speciation?
Sympatric speciation can be caused by a random mutation within the population that has impacted the reproductive behaviour
1) this may cause individuals to perform a different courtship ritual
which may not be recognised by the other individuals within the
species
2) may also cause individuals within the population to be fertile to
different time of the year, applies to plants and animals
