A Fish In This Lake Evolved Into 850 Different Species

When conditions are just right, one species can turn into hundreds in a short period of time. Welcome to the weird world of adaptive radiation.

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Sources:

[Skeptical_Numbat]

Lake Malawi isn't just a hugely long & wide lake. It's also surprisingly deep. Although it's only a respectable 292 metres deep on average, at its deepest, it's an astonishing 706 metres deep!

[bulletgrazer]

Oh, Lake Malawi! I had an Ichthyology professor who's spent decades cataloguing and studying the fish there. Given half the chance, he'd spend long chunks of class time talking about the stuff he had done there, like the dozens of hours he'd spent SCUBA diving the lake.

[FoxyFoxyShazam]

No shade, but I think it's funny they were talking about the diversity of lake Malawi cichlids and with 850 species to choose from still landed on using a discus (South American cichlid) graphic in the beginning.

[dragonsscorn]

Something not stated in the video is that this speciation only reproductive barrier is morphological difference, meaning if they can't see each other well then hybridization happens. Malawi does experience natural periods of increased turbidity during which most cichlids behavior tends to be more foraging focused. But human activity can/does increase lake turbidity. As the lake gets more cloudy, the higher the risk of species hybridization

[cosmoplakat]

This is fascinating, and I'm a freshwater fishkeeper, tho I never kept cichlids. Two of the species you showed, discus at 1.23 and green terror at 1.00, are South American in origin. Mbuna cichlids from L. Malawi are one type of very popular aquarium fish, but the other African Great Lakes have their own very diversified cichlid speciation with popular aquarium species - shell dwellers from L. Tanganyika and others from L. Victoria. Worldwide, there are 4000+ species. There are also many hybrids in the aquarium industry - flowerhorns, which have to be kept alone in a large aquarium (55+ gal) and blood red parrots are two examples.

[jasonseymour]

Lake Victoria is even crazier. Perhaps an additional video could dive more into the Rift Lake cichlids, their lakes, and how politics, wars, and disasters that are destroying them.

[l.n.]

I always used to wonder how scientists could determine that birds were the same species when the male and female looked so drastically different. It's amazing how species evolve and differentiate.

[xXMilk__DrinkerXx]

This is the first time I'm seeing one of Jaida's videos. She KILLED it. Very fast paced, but easily digestible, and interesting flow of info presented with a pretty entertaining delivery. Keep it up!

[Fusako]

Me, as a Live Fish keeper "That has to be either Malawi or Tanganyika" I love the African rift lakes for their interesting (and often problematic) water conditions.

[cboyles]

I've heard of Lake Malawi and I've known it contained cichlids. That is the extent of what I know about it. This is why I love SciShow and other channels of that ilk. I love learning about things that I'm woefully ignorant of. Thanks guys. Also I'm glad you're doing well, Hank 😄👏

[MandrakeFernflower]

Lake Malawi also has a bunch of weird exclusive sponges - the so called "Malawispongiidae"

[OhMyGoshItsALeg]

More Jaida videos, hooray! This residency program is leading to some fascinating stuff already.

[AaronGeo]

It's crazy how such a simple enviroment can have so many fish species

[sly]

My country Malawi. Thanks for this video. 🇲🇼🇲🇼🇲🇼🇲🇼🇲🇼

[superkamehameha]

Here before they discovered another species in that lake

[timothygreer]

1:21 While that is in fact a cichlid, it'sa Discus from the Genus: Symphysodon which are native to the Amazon basin. It's a member of the subfamily: Cichlnae which are the New World Cichlids.

[Ozraptor]

Another factor likely driving speciation in the Rift lakes are their unusual mode of reproduction (for a fish). Lake Malawi cichlids are predominantly mouth-brooders & substrate spawners with the young being reared by the parents and most species don't disperse far from their original home even after maturing. This makes it much easier for reproductively isolated populations to develop in close proximity to each other within the same lake.

[coeal]

first mention of Lake malawi, as a fish keeper, i instantly though "ah yes, the cichlids" xD
go to a professional fish keeping store, and i guarantee they will have an entire section dedicated to dozens or hundreds of cichlids

edit: awwww, kinda wish you would have mentioned the strange way some of the cichlids breed. for example, theres a few species of cichlids that "eat" their newly hatched young. holding them in their mouth to protect them from predators.. theres also species that dig holes under large rocks to lay their eggs, before refilling the hole

[acscordis]

Speaking as someone who holds Lake Malawi very close to my heart, please come and experience the country for all it's beauty, it has so much to offer.

[Fomites]

In 2011, I lived about 20 kilometres from the eastern shore of Lake Tanganyika in a geological exploration camp in Tanzania and had a patient with schistosomiasis that he picked up (we think) in Lake Malawi whete he worked for a while. He had ascites with a huge uncomfortably swollen abdomen from this. I managed to organise some praziquantel from a distant place for him as I departed back to here in Australia. My colleagues there told me the praziquantel fixed his illness. So cheap, nontoxic and easy to administer yet so effective.