Genetic drift, bottleneck effect and founder effect | Biology | Khan Academy
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- Опубликовано: 28 июл 2016
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Genetic drift, bottleneck effect and founder effect
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Wow😍 thank you so much I never understood genetic drift before!!
That was so interesting. So much stuff makes sense thx to your work. Thank you.
Explained so nicely. Great effort. Thanks
This is so helpful, I finally understand this!
Thank you so much for this video. Excellent explanation!!!!
More than randomness in the outcome of which individuals from the sample reproduce, Random Genetic Drift can be thought as randomness in the outcome fecundation from the heterozygotes: Even though it is expected a 1:1 ratio of transmission of each allele, the lesser this genotypes reproduces, the larger the chance its contribution to the next generation's gene pool will be off 1:1.
Didn't understand this until now thankyou!
Great video! It was really helpful
Thanks so much that was helpful.....!
Thank you. Very soothing voice and nice handwriting.
BLESS YOU FOR THIS
Best easy to understand
Wow! I've never had such a selection whith captions.
Why did you guys delete the last video on Evolution?
0:54 The laugh was great welcome to this lesson.
Thanks
great video!!
thank you!!! ❤
What is the reason of the actual population size being smaller than the effective population size? Any answers will be really heplful
Amazing video
whats up with the graph being 3:7 when there are 5 with a ressive trait and 5 without? and there is only 1 white rabbit??
I thought genetic drift was a category under bottleneck effect. I thought bottleneck effect was simply the decrease of a population and alleles.
thanks
Lots of love from kashmir
Salman, the man
I suppose an example of genetic drift and natural selection (and artificial) is a recovery project for a species of birds (I don't remember the details). Some eggs were laid on the outer parts of the nest, which would not have hatched, but were moved to the middle by the people to have more birds survive. After some generations a majority of the birds were laying eggs on the outside. So the people stopped moving the eggs at all and after some time most eggs were laid in the middle of the nest.
the new zealand chatham island black robin :)
Sosig
@@who5563 WHERE'S THE LAMB SAUCE?
@@HorkSupreme ikr
Would the recent Austrialian bush fire be an example of the bottleneck effect?
probably, i mean i'd say so
Great!, Can we account genetic drift for the emergence of new Kind/ Family or new species only ?
Linnéan taxonomy is obsolete, it doesn't work very well with evolution, since it was only designed to be a kind of snapshot of what life forms exist today.
In modern science, we use cladistics, instead. A system of branching lineanges.
So, your question doesn't make sense in modern science.
@@antiHUMANDesigns cladistics at the end of the day is based on assumptions, not an evidence. Where are all the intermediate fossils?
@@yahwayapps7947 Based on what assumptions?
Clades is phylogeny is derived from genetic analysis.
Take all of the DNA we have sequenced from all different species, plug them into a computer program, and the program spits out a phylogenetic tree that represents their relationships, each with a confidence level.
The tree you get matches what we see in the fossil record, as well.
Where are the intermediate fossils? Everywhere. They're all intermediate. Have you ever seen a fossil that's not intermediate?
@@antiHUMANDesigns the program doesn't magically build the tree, it needs an algorithm to run - which is given by Human.
@@antiHUMANDesigns the reason we have the concept of punctuated equilibrium is fossil records are not supporting the macro evolution hence, no tree. So better to switch to an assumption /algorithm to draw the tree. You are classifying them based on how close they are becuase first you assumed all life branched our from single/common ancestor
All horizontal or loss of information. Where do we gain information?
mutation.
The lecture was not about mutation and positive selection, only the potential loss of genetic variation.
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Natural selection (selection of favorable traits) + genetic drift (randomness)= evolution
So, evolution is not equal ONLY to natural selection (as we often equal those), but also it has influence of randomness or genetic DRIFT.
There are even other mechanisms
1.45 this is discrimination against pink and yellow dots
3.56 "whether you're brown or whether you're white, it confers no advantage." yessir
"Drift" means ratio change in phenotype (genotype/ allele expression) of a population: e.g flower BED changing from purple to white over generations. (Ratio -- 9 to 1, then 8 to 2, etc.)
It doesn't tell us whether the phenotype ratio-change is being selected for or a spandrel.
The way some define "DRIFT" makes it seem like spandrel development is an evidenced fact rather than marxist [e.g gouldian] conjecture.
...
Similar thing happened with "adaptation" and "sexual selection." ...The "marxists" just don't care about anything other than politics and cope. And don't get me started on "disorder."
....
When asserted-spandrels are studied they are found to be selected traits.
I don't know of any true spandrels other than bone color and MAYBE momma whale/ dolphin (and maybe her sonS) protection of a dead calf.
I don't know. Japanese and, some, south Korean mutations for lack of smelly body odor compared to the Indian subcontinent's tendency for strong body odor... I don't think it was random chance. Some women are picky, some are not. Some women are forced to marry, others are not.
God gene
Whats the narrators name
Sal Khan
Founder of Khan Academy
sheesh
*natural selection is a mechanism of creation and not exclusive to the THEORY of evolution
N o
No, natural selection is not a mechanism of the creation HYPOTHESIS.
+ak Hypotheses can be falsified. *Creation fable.
+ak Hypotheses can be falsified. *Creation fable.
Please don't go correcting people, there's a reason why the academic world is atheist, perhaps you should think about that.
Lgbtqia rainbow species
Khan is a MUSLIM Name 😂😂 are you MUSLIM sir
No, it comes from the turkish word meaning chief or ruler.
@@AJ-fv9ll yeah but it's a MUSLIM name
@@MyFather7865 Yeah he is a muslim.His mother is from India (Bengal)and father is from Bangladesh.
@@ashirt2100 how do you know. He is American
@@MyFather7865 Search up where is Salmon Khan from
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