Lecture 3: Evolutionarily Stable Stategies

By gabriellagirma1 | Updated: Feb. 15, 2024, 7:45 p.m.

Slideshow Video

SHARE THE AWESOMENESS

Education

create your own animated videos for free

_abc cc

* Powtoon is not liable for any 3rd party content used. It is the responsibility of each user to comply with 3rd party copyright laws.

Embed code

Select a size, the embed code changes based on your selection.

_abc Powtoon Transcript

Evolutionarily Stable Strategies
Lecture 3 Review
By: Gabriella Girma
What are Evolutionarily Stable Strategies?
Or ESS
Definition:
ESS are optimal behaviors that are favored over others, but only for a particular task
There are 2 types:
Pure or Mixed ESS
Pure ESS
This is when a single strategy is favorable, so only this one is displayed in the population
Pure ESS
Other strategies cannot be favored or outcompete the strategy with pure ESS, it is also difficult to find an example of it in nature
Mixed ESS
This is a source of variation in the population because mutiple stategies are equally favored in the popultion
Example of Mixed ESS
Digger wasps display mixed ESS
Example of Mixed ESS
Digger wasps have 2 strategies present in their population
Example of Mixed ESS
There are: 
      - Diggers that dig up their own burrows
      - Borrowers that use abandoned burrows made by diggers
Example of Mixed ESS
This ties in with frequency- dependent selection
Example of Mixed ESS
Frequency- dependent selection is when the fitness of a trait or behavior depends on its frequency in the population 
Example of Mixed ESS
This shows frequency-dependent selection because diggers are necessary for borrowers to exist
Example of Mixed ESS
If there are many diggers, there will be more abandoned burrows and the population of borrowers will increase
Example of Mixed ESS
If there are too many borrowers, the trait becomes less favorable, so the population of diggers will increase
Example of Pure ESS
This would be pure ESS if there were only digger wasps and no borrowers, just one favored trait
Example of Pure ESS
This would most likely be directional selection, since there would be a shift towards the single favored trait
Disruptive Selection
Another type of selection is disruptive selection, which is when there are 2 extreme  favored traits. This could also go with mixed ESS, since there would be multiple favorable strategies.
Stabilizing Selection
In addition to disruptive and directional selection, there is stabilizing selection. This reduces genetic variation because average traits are selected for and extreme traits are selected against.

Lecture 3: Evolutionarily Stable Stategies

Copy this link to share with friends and colleagues:

WELCOME TO POWTOON!