Reproductive isolating mechanisms. Flashcards
What is the definition of reproductive isolating mechanisms?
They are defined as any factors which prevent individuals from different populations breeding.
Why are RIMS important to speciation?
In speciation there needs to be some form of a barrier to keep the different populations isolated long enough for speciation to occur. RIMS are what ensure this.
What are the two types of RIMS?
- Pre-zygotic RIMS
2. Post-zygotic RIMS
What are pre-zygotic RIMS and how do they allow for speciation to occur?
Pre-zygotic RIMS act before babies are made (before fertilisation of the egg occurs). They prevent gene flow between populations and therefore allow for speciation to occur.
What kind of pre-zygotic RIMS are/can be present in sympatric speciation?
Structural or morphological Isolation. Gametic Isolation. Ecological Isolation. Temporal Isolation. Behavioural Isolation.
What is structural or morphological Isolation.
When the structures required for mating become too different over time which physically prevents fertilisation between populations.
What is gametic Isolation?
Where the eggs of one populations become incompatible with the sperm of the other population preventing fertilisation from occurring.
What is ecological Isolation?
Ecological Isolation is due to differences within the same ecological location which prevent the two populations from coming in contact.
What is temporal Isolation?
Temporal means time and temporal Isolation is due to the two populations having differences in breeding behaviour such as differences in breeding times and breeding seasons.
What is behavioural Isolation?
Behavioural Isolation is due to differences in mating behaviours between the different populations.
What kind of pre-zygotic RIMS are present in allosympatric speciation?
Geographical Isolation.
What is Geographical Isolation?
Where physical barriers prevent individuals from different populations mating.
What are post-zygotic RIMS?
Post-zygotic RIMS is when interbreeding is prevented after the zygote is formed.
What is a zygote?
The cell formed by the union of an egg cell and a sperm cell.
What are the 3 types of post-zygotic RIMS?
- Hybrid Inviability.
- Hybrid Sterility.
- Hybrid breakdown.
