Modelling Interspecific Competition

This video tutorial provides an introduction to Lotka-Volterra competition modelling, including derivations of zero-growth isoclines and how to make predictions based off of these plots. It was presented to an introductory undergraduate ecology class immediately following a lecture on logistic population growth.

Answers to the problems at the end of the video:
1) The Bison will out-compete the elk and drive them to extinction.
K1 = 200, K2 = 100, K1/α = 50, K2/β = 100
2) This scenario would result in species co-existence.
K1 = 1500, K2 = 500, K1/α = 3000, K2/β = 2000
Intercept: 1428 bluegill and 143 small mouth bass (see comment below for more details)

[GReid-olgk]

I'm taking an accelerated course and my professor blew through this. Thanks for the in-depth explanation. Take care.

[tedboo]

Thank you soooo much! This was really useful! Especially the Lotka-Volterra part when you were explaining chipmunk and squirrel competition :)

[khumbulanizondo]

I am writing a test tomorrow on this, and you just explained it adequately for me to do better. Thanks

[michellehotchkiss]

i was so lost on isoclines until i watched this, you just saved my ecology mark bless you

[danielhao]

I can get an A just by watching your videos.. Thank you so much for making my life easier!

[manikantakolasani]

I love u


Seriously u r the angel in my life u made my concept so clear

I have never ever seen such a good explanation

[JayBeePolitics]

Thank you for your help, I have an exam later today and you made it very clear and easy to understand. :)

[Asnxmiduhyo]

This was super helpful, clear and easy to follow! Thank you!! 

[monmon]

So am I correct in thinking that Lotka-Volterra interspecific competition modelling cannot be depicted by a sigmoid curve? I know that these equations are modifications of the logistic equation for intraspecific competition, so does that mean sigmoid curves do not describe interspecific competition at all? Thank you for explaining these equations so well!

[PunmasterSTP]

"Overall chipmunk effect" in "squirrel equivalents", for some reason I love those terms! 😆

[jamesgachinu]

Why would Bison out-compete the elk and drive them to extinction yet k1/alpha is less than k2 and also k2/beta is also less than k1??? I thought this was to be an unstable co-existence, could someone explain please?

[anishsubedi]

Wow! Thank you so much such an interesting and easily put lecture! Truly inspiring.

[luispenaloza]

You have a gift for teaching. Thank you!

[livingonmars]

thanks, but i still dont quiet get it. But it would be good to know the steps for the examples outcome, and to know if the answers wwe get is true

[a.h.]

thank you! you explained it way better than my professor

[vidhyasatha]

Awesome video and good explanation thanks for this video.
can you explain How can we find out unstable or stable coexist using this equations?

[farahfazloon]

I was so panicky because I had to read the chapter for class for tomorrow and take an online chapter quiz tonight and I didn't understand a word of this in the textbook. Thank you so so much! You've no idea how much you've helped me ! Also quick question the equation you had was dN1/dt=r1N1 [k1-(N1+aN2/k1).. i was wondering how this is different to where the k1 in the numerator is replaced by a 1. Because the equation I have in my textbook is dN1/dt=r1N1 [1-(N1+aN2/k1) . Just wondering what the difference is?thank you!

[wayne]

Hi there! Thanks for the lecture! I still wanna ask if the two populations stabilize when on the isocline?

[Eggynick]

this video really helped but id love to know if i did the problems right can u post the answers?

[Mugetsublade]

Thanks a lot for the the in-depth explanation. Through the video i wondered if a > B, species 2 will aways
competitively exclude species 1?