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For the first time, researchers have observed two cases of asexual reproduction in condors. And it also turns out that whales are much hungrier than we thought.

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Sources:
https://www.researchgate.net/profile/Elizabeth-Thompson-13/publication/254907851_Analysis_of_Relatedness_in_the_California_Condors_from_DNA_Fingerprints_1/links/0f31753b37e66d37cc000000/Analysis-of-Relatedness-in-the-California-Condors-from-DNA-Fingerprints-1.pdf
https://academic.oup.com/jhered/advance-article/doi/10.1093/jhered/esab052/6412509
https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/parthenogenesis
https://bmcbiol.biomedcentral.com/articles/10.1186/1741-7007-8-101
https://www.nature.com/articles/hdy201257
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3497136/
https://www.tandfonline.com/doi/abs/10.1080/00071666508415546
https://anatomypubs.onlinelibrary.wiley.com/doi/abs/10.1002/aja.1000330104
https://pubmed.ncbi.nlm.nih.gov/5656917/
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.619.8903&rep=rep1&type=pdf
https://pubmed.ncbi.nlm.nih.gov/19276631/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2391206/
https://stories.sandiegozoo.org/2021/10/28/san-diego-zoo-wildlife-alliance-conservation-scientists-report-first-confirmed-hatchings-of-two-california-condor-chicks-from-unfertilized-eggs/
https://www.sciencedirect.com/science/article/abs/pii/S0304380015004652
https://www.nature.com/articles/s41586-021-03991-5
https://press.springernature.com/baleen-whale-prey-consumption-based-on-high-resolution-foraging-/19726018

Images:
https://www.istockphoto.com/photo/california-condor-gm499264973-42520806
https://www.istockphoto.com/photo/california-condor-gm153586890-16834915
https://www.istockphoto.com/photo/california-condor-gymnogyps-californianus-gm169975455-24852331
https://commons.wikimedia.org/wiki/File:Bdelloid_Rotifer.jpg
https://www.istockphoto.com/photo/komodo-dragon-gm93173130-4113701
https://www.istockphoto.com/photo/condor-pair-gm1072281610-286952455
https://commons.wikimedia.org/wiki/File:Gymnogyps_californianus_-near_Hopper_Mountain_National_Wildlife_Refuge,_California,_USA_-adult_and_chick-8_(1).jpg
https://commons.wikimedia.org/wiki/File:California_condor_family_(19940221508).jpg
https://www.istockphoto.com/photo/california-condor-poses-gm178497886-21308173
https://www.istockphoto.com/photo/condor-gm495123612-77832123
https://www.istockphoto.com/photo/california-condors-gm468595354-61107238
https://www.istockphoto.com/photo/humpback-whales-feeding-megaptera-novaeangliae-in-chatham-strait-alaska-mouth-open-gm1290173534-385638777
https://www.istockphoto.com/photo/blue-whales-sri-lanka-april-2012-gm637250780-113569449
https://www.istockphoto.com/photo/bubble-net-feeding-humpback-whales-in-the-waters-of-bristish-columbia-canada-gm1218298321-355944466
https://commons.wikimedia.org/wiki/File:Humpback_whale_baleen.jpg
https://www.istockphoto.com/photo/krill-drifting-underwater-in-the-st-lawrence-estuary-in-canada-gm1069237662-286021351
https://www.flickr.com/photos/cmichel67/47539894201
https://www.istockphoto.com/photo/whale-tail-gm497103259-41660586
https://www.flickr.com/photos/noaaphotolib/9787178253
https://www.istockphoto.com/photo/humpback-whale-feeding-gm941491408-257329948
[♪ INTRO].

California condors are the  largest birds in North America, and they’re also critically endangered. At one point in the 1980s, there were fewer than 30 individual birds in the entire species.

Since 1988, a captive  breeding program has bolstered those numbers to over 1000. That doesn’t leave a lot of genetic diversity  to work with, so the scientists in charge of that program have been carefully  selecting mates to create the most diverse population they can. But last week, we learned that a couple of female condors took matters into their own wings.

They laid eggs that developed into  offspring without any help from a male. The details are in a new paper out  last week in the Journal of Heredity. These researchers report the first two known cases of parthenogenesis in California condors.

Parthenogenesis is a form of reproduction  where the female produces eggs that develop into embryos without  ever being fertilized. Some species of insects and  other invertebrates have evolved to only reproduce through parthenogenesis. Some other species can reproduce in this fashion, but only do so when a male just  can’t be found to fertilize the eggs.

This has been reported in  snakes, lizards, and turkeys. Though this is probably one of the  most solid reports in a bird so far. The genomes of the birds in the condor  breeding program are carefully monitored, so the researchers were able to work  backwards to figure out what happened.

And here’s the weird thing: the two  condor females had been housed with males, and had laid eggs with them before. It  wasn’t like a fertile mate wasn’t available. Which makes this the first time that  parthenogenesis has ever been reported in any bird species where we know for sure  the female had access to a mate.

This discovery could be big news  for the conservation of the species. For one thing, if all you need is one one  female bird to found a breeding population, that could help their range expand faster. That’s because these offspring aren’t  female like their parents, thanks to the way that sex chromosomes work in birds.

Females have one Z and one W  chromosome, while males have two Z’s. These parthenote chicks would have gotten  a Z from their female parent, which got duplicated at some point to make  them ZZ -- so they are male! Which means that theoretically, you  now have males and females that can reproduce in the conventional way  from as few as one individual.

This could also be a way of getting fatal  gene mutations out of the gene pool. The exact way this goes down is a bit  complicated, but basically, these chicks have two sets of chromosomes, but a lot of the  versions of genes, or alleles, on those two chromosomes end up being identical. When the offspring get one allele from  each parent, there’s a decent chance they will be different from each other.

If one of those alleles is harmful or even  fatal to the bird, they might get a healthy one from the other parent and be ok. But because the genetic  diversity in condors is so low, that chance is lower than usual. Either way, that harmful allele  is still lurking in their genome to potentially pass on.

Parthenotes, however, are extremely  likely to get a double whammy, getting both versions of a harmful  allele from their single parent. This may very well kill the bird. Which is bad for the bird, but  good for the population overall, because it can’t pass those  harmful alleles on if it is dead!

Which makes parthenogenesis a potential  double-edged sword, and ultimately, we don’t know yet whether it’s helping or hurting. In fact, neither chick survived  to have offspring of their own. Even so, these parthenogenetic parents  raise questions about what other species could be reproducing through parthenogenesis, and what that capability might  mean for conservation efforts.

And California condors aren’t  the only big, charismatic animals we’re still learning more about. New research published this  week in Nature suggests that whales are a lot hungrier than we knew. Like three times hungrier.

An international team of researchers set  out to figure out just how much large baleen whales, like blue whales  and humpback whales, eat. These whales take gulps of water and then  force it back out through tough bristles in their mouths, expelling  the water while filtering out tiny fish and krill for them to chow down on. The researchers attached GPS devices to  the whales to monitor their movements and figure out when they were eating.

They also photographed the  whales with drones to measure how big they were, and by  extension, how much they could eat. In places where they observed whales eating, they would measure the population  of prey species like krill. And with that information,  the researchers were able to estimate how much the whales eat.

And it turns out that whales eat a lot. An eastern North Pacific blue whale can  consume 16 metric tons of krill per day. Previously, scientists thought that  all of the whales in the region of the.

Pacific Ocean from Canada to Mexico eat about two million metric tons per year combined. This finding suggests that they actually  eat more than six million tons of food. And while that’s impressive, understanding  how much whales eat is really important for understanding ocean ecosystems.

Because eating more food means pooping more poop. And whale feces contains a ton of iron, which  is a critical nutrient for phytoplankton. And conveniently, krill feed on phytoplankton.

So the whales eat the krill and then poop  out iron near the water’s surface, which helps phytoplankton grow, which krill  colonies eat, and then the cycle begins again. Which also explains why, when whale  populations diminished due to commercial whaling, krill populations  actually shrank with them. Even though fewer whales were eating them.

Since phytoplankton also consume  carbon dioxide through photosynthesis, restoring whale populations  could actually increase the amount of CO2 that gets  pulled out of the atmosphere. In fact, the researchers think that when  whale populations were at their peak, they probably did as much for atmospheric  carbon removal as forests. So it turns out that baleen whales  don’t just have massive appetites.

They, and their poop, are massively  important to the global carbon cycle. Thanks for watching this episode of  SciShow, and a huge thanks to this month’s. President of Science, Matthew Brant!

Your support means a lot to us, and we  really couldn’t do it without your help. If you’d like a shot at becoming the  President of all science yourself, you can get started at patreon.com/scishow. [♪ OUTRO].