#biology

[muffinworry]

Hey don't cry, okay? We just found Attenborough’s long-beaked echidna, a species thought to be extinct for the past 60 years.

[bogleech]

I knew poinsettias "faked" having big flowers by just turning some leaves red but I didn't know the real tiny flowers in the middle looked like such idiots

[mindblowingscience]

By using antibodies from a human donor with a self-induced hyper-immunity to snake venom, scientists have developed the most broadly effective antivenom to date, which is protective against the likes of the black mamba, king cobra, and tiger snakes in mouse trials. Described in the journal Cell, the antivenom combines protective antibodies and a small molecule inhibitor and opens a path toward a universal antiserum.

Continue Reading.

[hawkpartys]

Black-crowned Night Heron (Nycticorax nycticorax) observation by eleggua

happy pride

[trees-expertise]

Literally me in my lectures

The best photo I took at Dashcon 2

[autism-freaks]

I think it's a common misconception that domesticating animals is somewhat like enslaving them. It really is more of a symbiotic relationship. No wild animal would have willingly put up with early humans if they didn't get something out of it. Wolves wouldn't have stayed with us and become dogs if they weren't getting food and safety out of it. Many large herbivores that are now domesticated could and would have easily trampled their early human captors or broken their enclosures open if they didn't have a reason to stay. Sometimes individual animals still do if we don't give them what they need.

The animals that have stayed with us for thousands of years have evolved to cooperate with us better. Dogs have additional facial muscles around their eyes that wolves lack in order to mimic human facial expressions. Sheep grow their wool perpetually while their wild counterparts don't because a bigger fleece means they're more likely to be allowed to breed and be kept around. Domestic dairy cows produce much more milk than wild bovine species and domestic hens lay more eggs. Do you know how energy costly producing eggs or milk is for an animal? It's pretty intense! They wouldn't be able to do that if we hadn't given them the food and safety from predators and the elements to.

And we really need to show these animals respect and gratitude for what they give us by taking excellent care of them. They gave up a lot to be with us, often including the means to take care of themselves in the wild. That's a huge reason why I'm not against using animal products, but I hate factory farming. They are still living, breathing creatures with needs and feelings. They deserve a comfortable life and, when the time comes, a humane death.

[organical-mechanical]

Fun fact: there’s a virus that makes bugs iridescent

disease that makes you beautiful then kills you

[bogleech]

The last few krakens and giant squids I saw in any media had entirely soft suckers like an octopus so now I'm wondering something. Giant squid generally have "tooth lined" suckers, and the colossal squid's two longer tentacles have suckers that evolved into full blown claws all over them.

[thrashershark]

Iconic

studied up

[hawkpartys]

this image came to me in a dream

[hawkpartys]

[bogleech]

Eatan

[hellsitegenetics]

String identified: at gaa a t a " t a a ' a gt t a a ." tat t a tc t a. at a tat

Closest match: Boloria caucasica genome assembly, chromosome: 3 Common name: Caucasian Fritillary

(image source)

my favorite grandpaism of all time is when he said "every time i learn a new person's name i forget the name of a fish." that shit has stuck with me for years. what did he mean by that

[lichenaday]

Baeomyces heteromorphus

I know that, superficially, the fruiting bodies of B. heteromorphus look like tiny mushrooms, but they aren't really. What we typically call "mushrooms" are the fruiting bodies of basidiomycete fungi, while the majority of lichens are ascomycete fungi. The big difference comes down to the spore-producing structures (which are generally not visible to the naked eye)--the basidiomycetes produce spores externally (stalk-like structures called basidia), whereas ascomycetes produce spores internally (sac-like structures called asci). Are these definitions ever gonna be helpful to you? Probably not. But IDK, maybe you come across one of these little guys on a hike some time and someone is like "oooo look at the tiny mushrooms!" and then you can be like "um actually . . . " and won't that be fun? Hmm, maybe this is why I don't have many friends . . .

images: source

[o-craven-canto]

How many living beings have there been on Earth -- ever?

It's a safe bet that the vast majority of them have been bacteria, to the point that counting bacteria alone should be enough; anything else vanishes into their rounding error.

Multiple sources suggest 10^30 individual bacteria are alive on Earth right now (that's a thousand billion billion billions, fwiw).

Biogeochemical evidence (Pearce &al 2018) place the origin of life around 3.8 billion years (Ga) ago, and bacteria or bacteria-like organisms must have been around since then. The earliest putative fossils don't look very different from modern bacteria in shape and size.

The life cycle of bacteria is quite variable, but a few hours seems typical for simple free-living bacteria (Lynch & Marinov 2017), and 10 hours seems the most common value outside a laboratory (Gibson &al 2018). Taking 10 h (1/877 of a year) as average, bacteria have been around for about 3.3*10^12 generations. Assuming a constant population, that implies 3.3*10^12*10^30 = 3*10^42 cells -- but not so fast.

Biomass on Earth has increased over time, with large jumps corresponding to major evolutionary advancements. Crockford &al 2023 helpfully estimate a 20-fold increase in global productivity correspoding to the appearance of photosynthesis around 3.5 Ga, a 10-fold increase with the appearence of oxygenic photosynthesis some 2.4 Ga (with a hypothetical overshoot and collapse that I'm going to ignore), and a 10-to-50-fold increase with the ascendance of multicellular life. This implies that the vast majority of life has lived just in the last half a billion years!

To simplify Fig. 1 in the cited paper, I'm making a model where global productivity compared to present is 0.0001 from 3.8 to 3.5 Ga, 0.002 from 3.5 to 2.4 Ga, 0.02 from 2.4 to 0.6 Ga, and then increasingly exponentially from 0.2 to 1 in the present time. From there I get 89% of all productivity ever in the last 0.6 Ga, and 99% in the last 2.4 Ga; since the margins of error are already very high, I can safely discount everything before 600 million years ago.

I'll be assuming that the number of bacteria on Earth is directly proportional to total global productivity in the last 600 million years, i.e. growing exponentially from 20% to 100% of the present number. In bins of 0.1 Ga, I get 0.6 Ga: 20%, 0.5 Ga: 26%, 0.4 Ga: 34%, 0.3 Ga: 45%, 0.2 Ga: 58%, 0.1 Ga: 76%, 0.0 Ga: 100%. From there, I get 311*10^6 bacteria-years relative to the current biosphere.

Combined with the 10^30 estimate for today, that is 3.11*10^38 absolute bacteria-years. Since I already calculated a line of bacteria experiences 877 generations per year on average, I get 2.7*10^41 bacteria overall -- one order of magnitude less than the naive(r) estimate I got in point 3!

Since the errors on this number completely swamp the amount of multicellular organisms and -- most likely -- Precambrian bacteria, I estimate about 3*10^41 (300,000 billion billion billion billions) individual organisms have existed on Earth since the origin of Life.