What are the two major types of reproductive isolating mechanisms?
1. Prezygotic. a) Geographic isolation. Two populations are separated spatially by something they can't or don't cross. b) Temporal isolation. Two populations are not sexually active at the same times. c) Behavioral isolation. This happens in birds a lot. The stranger isn't successful in mating because he's not doing the right song and dance. d) Mating can happen, but the sperm and egg don't recognize each other, so no fertilization takes place. 2. Postzygotic. a) Hybrids die in utero. b) Hybrids are born, but are weak and die quickly. c) Hybrids are infertile. d) Hybrids have greatly reduced fertility, e.g. ligers / tiglons / mules
5. What are the two major types of reproductive isolating mechanisms?Give examples and describe how they work?
1. prezygotic this is when something prevents the species from mating; either a physical or behavioral difference. example: two similar frog species mate at different times of year, preventing cross-breeding. 2. postzygotic the animals breed, but either the eggs are not fertilized properly, the embryo doesn't implant, the fetus miscarries, the offspring dies shortly after birth, or the offspring are sterile. example: when horses and donkeys mate, resulting in a mule, the mule is sterile. Since reproduction isn't successful unless your offspring also reproduce, this is consider unsuccessful breeding.
What type of reproductive isolating mechanism is described by a situation in which female fireflies only mate?
what type of reproductive isolating mechanism is described by a situation in which female fireflies only mate with males who emit light in a particular pattern? A. temporal (time) isolation B. Behavioral isolation C. mechanical isolation D. Habitat (location) isolation * thanks for your help
How does speciation actually work?
Speciation can occur when two populations are separated geographically, something called allopatric speciation. When members of a population split off from the larger group and migrate to a geographically separate location, that is when speciation starts to occur. Since this new group is in an entirely different location, there are different selection factors for them. The genes that helped a member of the parent population survive won't necessarily help a member of the new population. Gradually, the genes of the two different populations start to become more and more different. It will reach a point where members of either species can't breed with each other. Perhaps the genitalia shape becomes different in either species, or a male from one population can't impregnate a female from the other. It is also possible that the populations won't interbreed because they aren't sexually attracted to each other. You can say they are two different species because in order to be one species, they need to be able to interbreed.A classic example is the Galapagos finches. The islands are close enough to each other to allow migration, but far enough away to avoid interbreeding between populations. Because of this, a population of finches can become isolated, becoming a new species. Humans from different cultures are the same species because we are able to breed with each other (even though there are populations of humans that look quite different from each other). Because of the intermixing of human populations across continents, there hasn't been much of an opportunity for geographical isolation. There are other types of speciation; this is just one.Sources:Speciation
What are the types of reproductive isolating mechanisms?
Reproductive isolation expresses the concept that biological factors impede members of two species from producing viable offspring. Reproductive barriers can be classified into two categories, prezygotic barriers and postzygotic barriers. Prezygotic barriers impede mating between two species or hinder the fertilization of ova if members of two different species attempt to mate. Comparatively, postzygotic barriers prevent the zygote from developing into a viable adult, should fertilization between two different species occur. Prezygotic barriers: 1) Habitat isolation - two species that occupy different habitats within the same area may encounter each other rarely, if at all. 2) Temporal isolation - species that breed during different times of the day, different seasons, or different years cannot mate. 3) Behavioral isolation - certain behavioral patterns that attract mates or that are unique to a particular species are effective reproductive barriers. 4) Mechanical isolation - morphological differences can prevent successful mating. 5) Gametic isolation - sperm of one species may not be able to fertilize the eggs of another species. Certain biochemical processes may prevent sperm from penetrating the egg of another species, or, the sperm may fail to survive in the reproductive tract of females of another species. Postzygotic barriers: 1) Reduced hybrid viability - the interaction of genes between members of two different species may hinder the ability of the hybrid to develop into a viable adult. 2) Reduced hybrid fertility - if members of two different species produce viable offspring, the offspring may be sterile. This example is best illustrated by a mule, the hybrid offspring of donkey and horse. 3) Hybrid breakdown - some offspring from the first generation may be viable and capable of producing viable offspring. However, if such offspring mate with each other, or with either parental species, the resulting offspring of the next generation may be sterile.
3 types of reproductive barriers that can lead to speciation?
there are two types of speciation: allopatric and sympatric. For allopatric speciation there must be a geographical separation between two populations (a mountain for example). For sympatric speciation there are a LOT of possible barriers. If the question is what you said (with no reference to allopatric or sympatric) here is what I would say: 1. A geographical barrier that blocks one population from another population. A mountain, body of water, etc. 2. The two populations may not recognize each other as being the same species and therefore not mate with each other. After a few generations they will evolve separately from each other and no longer be 2 populations of the same species but instead 2 separate species. 3. Two populations may physically not be able to mate with each other and therefore evolve seperately. Speciation all has to do with isolation of two large population of the same species, once they are isolated they evolve separately and change into different species because of evolution.