14.3 Reproductive Barriers Flashcards
What do reproductive barriers isolate
the gene pools of species
How many main types of reproductive barriers are there?
2
What are the 2 main types of reproductive barriers?
Prezygotic Barriers and Postzygotic Barriers
How many types of Prezygotic Barriers
5
What are the 5 types of Prezygotic Barriers
1) Habitat Isolation
2) Temporal Isolation
3) Behavorial Isolation
4) Mechanical Isolation
5) Gametic Isolation
Habitat Isolation
if you are in different habitats you cannnot mate and reproduce
What is an example of Habitat Isolation?
land snakes cannot mate with water snakes
Temporal means
time
Temporal Isolation
mating seasons are different so they cannot mate and reproduce
What is an example of temporal isolation
lillies mate in the day and chrysthanseum mates in the night
Behavorial Isolation
different organisms have different courtship rituals
What is an example of behavorial isolation
finches won’t recognize the courtship rituals of the song and dance of a blue footed booby
Mechanical Isolation
reproductive parts of organisms are incompatible
What is an example of Mechanical Isolation?
Red and purple sea urchins -> one has surface proteins that do not allow the sperm to fuse with the egg
Gametic Isolation
molecular incompatibility of the egg and the sperm (doesn’t fuse)
What is gametic isolation usually caused by
different chromosomal numbers
Post Zygotic Barriers
barriers formed after the egg is fertilized and the zygote is formed
How many types of Post Zygotic Barriers are there
3
What are the 3 types of Post zygotic barriers
1) Reduced Hybrid viability
2) Reduced hybrid fertility
3) Hybrid Breakdown
Reduced Hybrid Viability
the hybrid is developed but the organism is weak and dies before reproductive age
What is an organism that proves an example of reduced hybrid viability
some types of salamanders
What is reduced hybrid viability caused by
the interaction/incompatibility of parent genes
Reduced hybrid fertility
strong organism; cannot reproduce
What is an example of an organism that proves reduced hybrid fertility
mule (horse + donkey)
Hybrid Breakdown
first hybrids are strong and can reproduce, but the 2nd generation cannot reproduce and is weak
What is an example of an organism that proves hybrid breakdown?
rice hybrids
What is hybrid breakdown caused by?
difference in the number/structure of chromosomes
Hybrid Zones
regions in which members of different species meet and mate, producing at least some hybrid offspring
