user12555: How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single cell? Also, why the population is rising in the animal kingdom including humans, surely, it cannot be other beings from different realms are coming to earth. I am so confused about this although I am a  practicing Buddhist. 

user254: How do we apply reincarnation to phenomena such as reproduction by binary fission?
I don't.

I don't understand it (the theory of rebirth) well, so I try not to use it nor rely on it.
If form is not self, then I'm not sure why you expect there's any one-to-one relationship between "a being" and "a cell".
A sheep is a multi-cellular organism -- do you count it as one being, or as several?

My "science" education teaches me that different theories are used for different reasons, to explain different phenomena. For example, the "theory of gravity" explains why things fall when you drop them, but the "theory of gravity" doesn't explain why water boils when you heat it.
So, part of understanding (or using) a theory is to know when and why to use it, what it's "useful" for, and what it isn't useful for.
I think the theory of reincarnation has some uses, for example:

It teaches that causes can have an effect, even if the effect doesn't seem to be immediate
It may help to decrease ego-centrism, e.g. the view that "Me, this life, is all-important -- and nothing else matters: no-one else, no other time".
It may promote disenchantment (see for example the quote in Samana Johann's answer); and equanimity (if something "bad" happens, does it help to consider that this wasn't the first time it has happened?).
It may help redirect attachment (the theory that a loved one still exists after death, though in a different form)
And more?

However, IMO, trying to relate it to cellular biology, as you did, is  completely off-topic: neither the purpose (use), nor the type of observation (phenomena), for which the theory is or was intended.

user10304: 
How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single cell?

As I understood Nagarjuna, a Being (Self) is neither the Skandhas, nor not the Skandhas; for a Being can't be obtained without the Skandhas. Then it can be said in our worldly wording that each amoeba is a Being though by binary fission; so is each Dolly an individual sheep. And life isn't created, for if it could we can assemble in lab.; even Frankentein needs that "lightening" to give it life. Therefore since life isn't created it can't be annihilated, just changes form of expression from each life-session. That's what called reincarnation, or better named rebirth. Reincarnation is specially for some Beings who are autonomous in it, or with mission.    

why the population is rising in the animal kingdom including humans

Because we are now in a declining minor Kalpas, according to Sutras. Things are deteriorating, so to speak, thus more lesser Beings are born. The 6 Realms are like the pyramid, the higher the fewer. In Buddha's time, more Beings are born from the celestial realms to the human world and vice versa, now there are more from lower realms. Homo sapiens is just a vast generalization, in it carried many favours.    

it cannot be other beings from different realms are coming to earth

It surely can. If the earth is only good for humans, or the earth also inhabited by non-humans? Why not? When a Being's Karma weight is right for earth, then Terra is the home. Personally I wonder if Saturn and Jupiter homes of the Asuras, maybe the Devas? For there rain diamonds. Different realms can't be seen via naked eyes, unless one has divine vision, or with special apparatus. 

I'm more concerned with the "in vitro meat". In reference to the answer in the beginning, how does this lab-meat feel (Vedanā)? If I contemplate, I kind of get that it must be in constant pain. If your skin is torn and flesh exposed, how do you feel? It would be the same for this meat-being sitting only just in plain air, or in the culturing fluid - unending pain.   
~§ Due to ignorant, we commit many crimes; they weigh us down, which we thought achievement. §~ 

user43: There is no literal rebirth of the same "being", Janaki. All entities, including "beings" are approximate abstractions.
Reincarnation is a metaphor for continuity of information and causation, presented in a way accessible to simpleminded ancient people.

user-1: 
How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single sell?Also, why the population is rising in the animal kingdom including humans, surely, it cannot be other beings from different realms are coming to earth.
I am so confused about this although I am a practising Buddhist.

If you want to become an even more confused Buddhist, then keep pondering this :)
If not, then stop pondering this and go practice.
You might also want to take a look at the Four Imponderables:

The four imponderables are identified in the Acintita Sutta, Anguttara Nikaya 4.77, as follows:
The Buddha-range of the Buddhas [i.e., the range of powers a Buddha develops as a result of becoming a Buddha];
The jhana-range of one absorbed in jhana [i.e., the range of powers that one may obtain while absorbed in jhana];
The [precise working out of the] results of kamma;
Speculation about [the origin, etc., of] the cosmos is an imponderable that is not to be speculated about.

These imponderables the Buddha advices not to contemplate, since they will only agitate and destabilize the mind, making it less suitable for practice.

12555: <p>How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single cell? Also, why the population is rising in the animal kingdom including humans, surely, it cannot be other beings from different realms are coming to earth. I am so confused about this although I am a  practicing Buddhist. </p>
 254: <p><strong>How do we apply reincarnation to phenomena such as reproduction by binary fission?</strong></p>

<p>I don't.</p>

<ul>
<li>I don't understand it (the theory of rebirth) well, so I try not to use it nor rely on it.</li>
<li>If form is not self, then I'm not sure why you expect there's any one-to-one relationship between "a being" and "a cell".
A sheep is a multi-cellular organism -- do you count it as one being, or as several?</li>
</ul>

<p>My "science" education teaches me that different theories are used for different reasons, to explain different phenomena. For example, the "theory of gravity" explains why things fall when you drop them, but the "theory of gravity" doesn't explain why water boils when you heat it.</p>

<p>So, part of understanding (or using) a theory is to know when and why to use it, what it's "useful" for, and what it isn't useful for.</p>

<p>I think the theory of reincarnation has some uses, for example:</p>

<ul>
<li>It teaches that causes can have an effect, even if the effect doesn't seem to be immediate</li>
<li>It may help to decrease ego-centrism, e.g. the view that "Me, this life, is all-important -- and nothing else matters: no-one else, no other time".</li>
<li>It may promote disenchantment (see for example the quote in Samana Johann's answer); and equanimity (if something "bad" happens, does it help to consider that this wasn't the first time it has happened?).</li>
<li>It may help redirect attachment (the theory that a loved one still exists after death, though in a different form)</li>
<li>And more?</li>
</ul>

<p>However, IMO, trying to relate it to cellular biology, as you did, is  completely off-topic: neither the purpose (use), nor the type of observation (phenomena), for which the theory is or was intended.</p>
 10304: <blockquote>
  <p>How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single cell?</p>
</blockquote>

<p>As I understood Nagarjuna, a Being (Self) is neither the Skandhas, nor not the Skandhas; for a Being can't be obtained without the Skandhas. Then it can be said in our worldly wording that each amoeba is a Being though by binary fission; so is each Dolly an individual sheep. And life isn't created, for if it could we can assemble in lab.; even Frankentein needs that "lightening" to give it life. Therefore since life isn't created it can't be annihilated, just changes form of expression from each life-session. That's what called <em>reincarnation</em>, or better named <em>rebirth</em>. Reincarnation is specially for some Beings who are autonomous in it, or with mission.    </p>

<blockquote>
  <p>why the population is rising in the animal kingdom including humans</p>
</blockquote>

<p>Because we are now in a declining minor Kalpas, according to Sutras. Things are deteriorating, so to speak, thus more lesser Beings are born. The 6 Realms are like the pyramid, the higher the fewer. In Buddha's time, more Beings are born from the celestial realms to the human world and vice versa, now there are more from lower realms. Homo sapiens is just a vast generalization, in it carried many favours.    </p>

<blockquote>
  <p>it cannot be other beings from different realms are coming to earth</p>
</blockquote>

<p>It surely can. If the earth is only good for humans, or the earth also inhabited by non-humans? Why not? When a Being's Karma weight is right for earth, then Terra is the home. Personally I wonder if Saturn and Jupiter homes of the Asuras, maybe the Devas? For there rain diamonds. Different realms can't be seen via naked eyes, unless one has divine vision, or with special apparatus. </p>

<hr>

<p>I'm more concerned with the "<a href="https://en.wikipedia.org/wiki/Cultured_meat" rel="nofollow noreferrer">in vitro meat</a>". In reference to the answer in the beginning, how does this <em>lab-meat</em> feel (Vedanā)? If I contemplate, I kind of get that it must be in constant pain. If your skin is torn and flesh exposed, how do you feel? It would be the same for this meat-being sitting only just in plain air, or in the culturing fluid - unending pain.   </p>

<p>~§ <em>Due to ignorant, we commit many crimes; they weigh us down, which we thought achievement.</em> §~ </p>
 43: <p>There is no literal rebirth of the same "being", Janaki. All entities, including "beings" are approximate abstractions.</p>

<p>Reincarnation is a metaphor for continuity of information and causation, presented in a way accessible to simpleminded ancient people.</p>
 -1: <blockquote>
<p>How do we apply reincarnation to phenomena such as reproduction by binary fission (amoeba) and creating animals like Dolly the sheep from a single sell?Also, why the population is rising in the animal kingdom including humans, surely, it cannot be other beings from different realms are coming to earth.</p>
<p>I am so confused about this although I am a practising Buddhist.</p>
</blockquote>
<p>If you want to become an even more confused Buddhist, then keep pondering this :)</p>
<p>If not, then stop pondering this and go practice.</p>
<p>You might also want to take a look at the <a href="https://en.wikipedia.org/wiki/Acinteyya#Four_imponderables" rel="nofollow noreferrer"><em>Four Imponderables</em>:</a></p>
<blockquote>
<p><em>The four imponderables are identified in the Acintita Sutta, Anguttara Nikaya 4.77, as follows:</em></p>
<p><em>The Buddha-range of the Buddhas [i.e., the range of powers a Buddha develops as a result of becoming a Buddha];</em></p>
<p><em>The jhana-range of one absorbed in jhana [i.e., the range of powers that one may obtain while absorbed in jhana];</em></p>
<p><em>The [precise working out of the] results of kamma;</em></p>
<p><em>Speculation about [the origin, etc., of] the cosmos is an imponderable that is not to be speculated about.</em></p>
</blockquote>
<p>These imponderables the Buddha advices not to contemplate, since they will only agitate and destabilize the mind, making it less suitable for practice.</p>
