Population Bottlenecks

Biology Professor (Twitter: @DrWhitneyHolden) teaches you about Population Bottlenecks, including what they are and why they matter!
Want a PDF of the final white board with all the answers written in? Check out my FREE NOTES here: tinyurl.com/BiologyProfessorN...

[@biswajitmohanty3251]

Excellent explanation so lucid and clear.... Thank you mai'm.....

[@Juanitasa24]

Thank you! Enjoyed your video.

[@BiologyProfessor]

No problem. Thanks for watching:)

[@alvaroakatico9188]

When I first saw the title I thought it was going to be on human population. This is my reason for clicking. Regardless, I found your presentation very professional and intriguing. Hello from Costa Rica 👋🏻🇨🇷

[@BiologyProfessor]

Thanks for saying Hi 👋🏻

[@bbtamuli5437]

Thanks...Very informative

[@BiologyProfessor]

Thanks!

[@normanschur8922]

Thank you I was watching Dr stone an I wanted to know how the six on the iss did the bottleneck and made the village now I know thanks.

[@sciencenerd7639]

thanks, this is an important topic

[@BiologyProfessor]

I agree

[@mayanksangam9205]

Thank you professor. It's helpful :)

[@Pharma-Notes.]

Thanks professor it is beneficial

[@BiologyProfessor]

You are welcome 🤗

[@virtualracer4324]

Hello professor!
I am your new subscriber
I am having a trouble in understanding the concept of alleles. Can you please make video on it. This will mean a lot 😇.
Also, I am preparing for my exam and was going through previous year question when a question got me confused.
Q) in peas, a pure tall plant (TT) is crossed with a short plant (tt). The ratio of pure tall plants to short plants in F2 generation is
A)1:3
B)3:1
C)1:1
D)2:1
The correct answer given in book is C
But I think answer should be B
Is it B or C and if C then how ?

[@BiologyProfessor]

The correct answer is C so your book is right. I think you are not correctly understanding the use of the word “pure”. It is used here to mean TRUE BREEDING (or homozygous, having two of the same alleles). So the question is not asking about the ratio of tall to short plants, instead it is asking for the ratio of TT to tt plants, which is 1:1 (because the other two possibilities in the cross are Tt). I have made a video about alleles and I will have it up in about 12 hours!

[@BiologyProfessor]

Here's that new video on alleles: ruclips.net/video/n-VAMxlkolY/видео.html

[@virtualracer4324]

@@BiologyProfessor Thankyou 😃.

[@virtualracer4324]

@@BiologyProfessor Yes, you are right, I didn't understand the meaning of 'pure' so I wasnt able to get the correct answer. Tt aren't pure so they can't be taken while calculating the ratio.

[@BiologyProfessor]

Personally, I don’t like to use “pure” in this context. “True breeding” (because all offspring will inherit the allele that matches the parent’s phenotype) is better than pure, in my opinion. Good luck with your studies!