Is it possible for different organisms to mate explain?

Yes it is possible. For instance a horse and a donkey can mate to produce a mule. This is a hybrid of the two and is itself sterile and incapable of producing offspring. Bacteria can also transfer genes between species. Generally with eukaryotes, however, mating rarely occurs outside of one's own species. This is because of many different factors.

1. Habitat isolation - two species that live in separate areas are unlikely to mate, even if they have matching "equipment" so to speak

2. Temporal isolation - sometimes species are only reproductive at certain times of year. If one species is active in spring and another in fall, they will be unable to mate.

3. Behavioral isolation - Animals are generally not attracted to other animals of different species. Sometimes there are courtship displays or procedures required for mating that are only done in the species in question.

4. Mechanical isolation - Some organisms just aren't going to have matching tools. A duck and an elephant, for instance, just aren't gonna do it. Poor duck.

5. Gametic isolation - Sometimes the sperm and eggs of different species are incompatible, or in the case of internal fertilization like humans practice (with sperm deposited inside the female's body in swimming range of the ovaries), sometimes the sperm can't survive inside the body of a female of a different species.

6. Reduced hybrid viability - Sometimes two species can fertilize one another, but the offspring produced is very weak. These offspring are very unlikely to reproduce themselves.

7. Reduced hybrid fertility - like mentioned above, mules are sterile. This means that even when horses and donkeys do mate, they don't produce fertile offspring.

8. Hybrid breakdown - Sometimes fertile hybrids can be produced, but their offspring are fertile.

Sometimes though, you do get matings between organisms considered different species. This should reveal that nature need not abide by our categories! Two different species USUALLY can't mate, but rarely, they do, and even more rarely, they produce robust but sterile offspring (like the mule). Rarer still, they may produce fertile offspring which go on to reproduce and become a species in their own right.

7.

physical barriers (an elephant could never safely couple with a duck), behavioral barriers (an elephant would never WANT to couple with a duck!), and reproductive barriers like