Speciation | Prezygotic vs Postzygoic Barriers | Forms of Reproductive Isolation

How do new species form you ask? This video has the answer, or at least talks about part of the process.
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Exmples of reproductive isolation: evolution.berke...
Definitions and a much longer discussion: bit.ly/2xQhaWS
Excellent article on: speciation:www.ncbi.nlm.n...
Speciation is the formation of one or more new unique species from a current species.
In order for one species to split into two or more, a faction within the species must not share genetic information with the rest of the species. This is called reproductive isolation. There are two main categories of contributors to this isolation, prezygotic barriers and postzygotic barriers, so named for whether they occur before or after fertilization.
Prezygotic barriers result when two groups within a species isolate themselves from one another in some way. Let’s look at some examples.
Temporal isolation occurs when members of the same species are active at different times of the day, month, or even year. More specifically, they breed at different times. For example, if some members of the group breed during the day and others breed during the night, they are isolating themselves from one another and not sharing genetic information. The same would be true for one group breeding in the spring and the other breeding in the fall, again, both from the same species.
Behavioral isolation is another, in this case, members of the same species behave differently, especially with mating practices. So these members may have slightly different mating rituals that don’t attract members of the other group, thus isolating who they mate with.
Others include mechanical isolation, where some members physically can’t mate with others, Habitat isolation, where the habitat occupied by members of a species differs and thus, breeding interactions differ, and gametic isolation, which occurs in aquatic animals. You can learn more about all these by following links in the description.
Now to postzygotic barriers.
Again, these barriers occur after fertilization has occurs, so mating occurs but no viable or fertile offspring is produced.
These include reduced hybrid viability, in which case there is successful fertilization, but development is not successful, or results in very weak offspring prone to early death.
Another example is reduced hybrid fertility, in which case a mating is successful at producing offspring (a hybrid of the parents), but that offspring is not fertile thus producing no offspring of it’s own. The classic case is a mule, the offspring of a male donkey and a female horse. The mule lives a full life and can function just fine except when it comes to reproducing unfortunately. This is one reason that donkeys and horses are considered a different species.
A final example of a postzygotic barrier is hybrid breakdown, in which offspring is produced, and that offspring may be able to reproduce, but that second generation will be weak and/or sterile.
Speciation with respect to reproductive barriers is a complicated topic which I have done my best to simplify, if this video helped you, give it a like, and if you have any questions, throw them in the comments.
If you want to learn about allopatric speciation vs sympatric speciation, watch this video, it’ll help. Thanks for watching, I’ll catch you next time.

[@amrdawoud5467]

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[@2MC]

Thanks for your support!

[@joemartinez8625]

Bro! You are great!! so much simpler than what my professor explained to us. Keep doing this. I enjoyed your sketching and color and pictures.

[@2MC]

Thanks Joe, sometimes professors complicate things.

[@josh8962]

You saved me man. I'm impressed how good some people can explain, respect

[@saffanakalista7248]

can you please do sequence and series? Thank you! you explain better than my teacher. love from Indonesia

[@2MC]

Thanks Saffanna! Can you explain a little more about sequence and series? I'm not sure what you mean.

[@saffanakalista7248]

2 Minute Classroom arithmetic sequences and series. a sequence of numbers such that the difference between the consecutive terms is constant. Like 2, 4, 6, 8..

[@sanjanan7109]

so much more helpful than articles that use big words that my simple dumb brain can't understand lol! thanks man!

[@2MC]

No big words needed here. And I'm confident your brain is just fine! (even I failed classes in school)

[@pariprahalad2909]

Can you please do a video on Balanced polymorphism and its variation? Thanks!

[@hanseru7831]

We just discussed this earlier, such a coincidence. I love your videoss!!

[@2MC]

That's awesome! And thanks for the love!

[@elixenramirez740]

Nice and easy. What a legend.

[@2MC]

You're too kind.

[@sarayugopal9363]

Great explanation...follower from india❤❤❤

[@AlJofe]

Hi, did you ever do the video on allopatric and sympatric speciation

[@2MC]

Not yet, but it's great to know there is interest in the video!

[@simrit6615]

i love how you explain, it helped a lot!

[@lauracabe]

great video, although what a tease with the allopatric speciation vs sympatric!

[@2MC]

I am a bit of a tease. The video is forthcoming, I hope to have it out before the end of the year.

[@TheSpeedy216]

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[@sarayugopal9363]

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[@Aya19557]

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[@2MC]

You're too kind.

[@DROIDFARM]

Liked and subscribed! Thank you from Texas!

[@2MC]

You are welcome!

[@user-ru2em1fw5c]

I'm looking for questions about reproductive isolation and speciation😥😥 do you have??

[@copernicannacinrepoc2491]

Great job explaining.

[@2MC]

Thanksss

[@jeevitharuth465]

thank you for your great work.

[@amanverma6958]

if testis of a male rabbit mature in December month and ovary of female mature in January month for sexual reproduction but reproduction does not occur it is an example of A. Temporal prezygotic isolation B. Mechanical postzygotic isolation C. Gametic solution D zygotic isolation

[@2MC]

That would be temporal isolation, because sexual reproduction is not occuring due to a temporal (time-based) event.

[@Flamma1205]

Hi! thanks for the great lesson. I've a little question though, in the beginning you said for speciation to happen a faction from within a species must not share its genetic material with the rest of the population through reproductive isolation, but my question is, if two organisms are not mating and not producing fertile offspring, doesn't that mean that they are already members of different species??

[@2MC]

Great question. There is a difference between "could" mate and produce viable offspring and "are" mating and producing viable offspring. For speciation to occur, a group that could mate needs to be separated in some way so that they are not mating.

[@Flamma1205]

@@2MC Great! I get it now! So it's like the two groups are not technically different species just yet, but they will be some period of time down the line, through reproductive isolation. So reproductive isolation is a mechanism of speciation and not a set of criteria to distinguish between members of already different species (that's what I used to think), right? Thanks for clarifying!

[@BioBloom10M]

Very helpful❤

[@empoweredbylove937]

Thank you!

[@2MC]

You're welcome!

[@pablogaray3928]

Hello. I would like to know of spontaneous speciation.

[@2MC]

👍 I'll add it to the list.

[@TheTopazChannel]

we are only doing 3 iso barriers: eco, geo, and mechanical. How do I apply that to this?

[@tayokristine]

Heyyy, that is one of my discussion topic choices for my plant bio class. This article helped me understand prezygotic isolation barriers better: www.ncbi.nlm.nih.gov/pmc/articles/PMC2607309/

[@2MC]

Thanks @Tay O! Love seeing help in that comments.

[@user-qs2nd8fu2u]

May I ask if you have a video about hybrid breakdown? Can it be solved?

[@anniewang9937]

Hello, which app do you use to do this wonderful videos?

[@matthew_bang]

Great video

[@2MC]

Thanks man!

[@deepdhankar]

Literally awesome!!❤

[@2MC]

Glad you think so!

[@alexanderlinhardt5750]

this is great!

[@2MC]

No Alex, you are great!

[@iplaygame1238]

Just saved me 8 hours of studying my bio teacher aint teach me nothin

[@aswin8063]

But u didn't say how these isolation leads to speciation ... How do they become a new species when no new alleles are introduced in them? They are literally isolated frm each other but how do new species form?

[@2MC]

Two reasons, they have different alleles in each group and their new environment may favor some alleles over others. Two, since they are separated any new mutations in their alleles will affect one group but not the other, and thus, over millions of years, you can get new species.

[@anotherdoseyt]

temporal isolation is the same thing as Seasonal isolation?

[@2MC]

Seasonal isolation is a form of temporal isolation.

[@hometz1557]

How reduced hybrid fertility become barrier since a mate between donkey and hourse reproduce mule??????

[@2MC]

Because a Mule is infertile, so it is technically not a new species. In order to be a new species, it must be able to mate and produce viable offspring.

[@JayJay-ve1iu]

Great 👍💙👆

[@kiranafridi667]

I wanted to ask that in parapatric speciation there is an extreme change in habitat which leads to reproductive isolation right, so why don't this apply to humans like if this applies then one living in northern areas could not breed with the one living in southern areas?

[@2MC]

There has to be complete separation for a long time. Homo sapiens are a relatively young species. Additionally, humans today move/live all over, and thus, spread their DNA all over, so it's extremely difficult to completely isolate a group of humans. Does that make sense?

[@kiranafridi667]

What if we isolate a group of humans.lets suppose then would it be applying then?

[@Celystial]

very informative & great videos, but you do sound very sleepy lol

[@2MC]

Haha, i'll try to work on that one.

[@baileyrogers1705]

thank uuuuuuuuu

[@2MC]

You are so welcome 👍

[@srchamp6363]

Hi. I love your videos and I want you to continue making videos. I want to make my own and I will soon because I got inspired by your videos like the channel intro one. Do you want to collab?

[@2MC]

Collabs are great, but you don't have any content uploaded yet. Contact me when you have some vids up so I can see them. Also, one of the biggest benefits of collaborating is to reach the audience of the other KZbinr and thus grow your subscriber base. You don't have much of a subscriber base, so you should work on growing that before collabing as well. Hopefully I hear form you in the future and we can get something done together.

[@Sam-hd3ks]

liked

[@2MC]

thx

[@shinchannohara2924]

How do you make these animinated videos

[@apoocumber4164]

speciation is such a finicky idea. imo, it should only occur when a species can no longer mate with another species via genetic incompatibility. (i.e chromosomal disparity). if it can mate, its the same species. sub species shouldn't be speciation.

[@Heresheis0818]

🙄👆🏽

[@srchamp6363]

Can you reply to my question below?

[@2MC]

Just did it :)

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I'm a green unicorn

[@2MC]

Really? And this whole time I thought they only came in red.

[@sahalae6443]

700th like

[@2MC]

I had no idea this video had so many likes! Thanks for making it 700.

[@noura3431]

Thank you!

[@toxicgummybear9101]

Thank you!

[@2MC]

You are welcome.