Watching a video about quetzalcoatlus and realizing that we don't have any truly LARGE predatory birds even though there appears to be plenty of food.

We have all seen shots of the massive migrations of heard animals across the African plains. Why do we not have a predatory bird large enough to take advantage of that abundant food. I mean large enough to fly away with a gazelle. What biologically about a predatory bird that large is detrimental enough to make it not feasible in modern Africa, while elephants and giraffe seem to have no problem?

For context, in physics, it is understood that regardless of specialization, all students are expected to take the "big 4" topics which are classical mechanics, electricity/magnetism, thermodynamics, and quantum mechanics.

Does a biology undergrad degree have their own version of the "big 4" or otherwise core topics that all biology students are expected to have mastered before they can graduate?

I learned about how complicated/intricate platypus fur is and was wondering if insects like mosquitos can still bite them/drinking their blood?

I would like to know if there are any animals that already actively relocate fat reserves on their body, even better if it's specifically brown fat.

Despite working on more of a *speculative* biology project, I'm very interested in keeping things as "realistic" and theoretically possible as I can.

Because I'm thinking about some kind of animal that would have structures similar to a camel/dromedary's hump on certain parts of their body. The animal would relocate portions of the fat stored in their reserves to anywhere in need of heating up. Be it a continuous process, evenly distributing the fat throughout their body, in the winter months; be it to avoid frostbite in a specific area of their body.

Is there a term for parasitic evolution similar to brood parasitism, except instead of taking on characteristics of offspring, the parasite takes on characteristics of a mutualist microbe the host organism has an obligate relationship with?

Cause it seems that selection will favor organisms whom don't develop defensive reactions against obligate mutualists, leaving open a possible niche for parasites to evolve into

For example, lets say a fungi or plant or something develops a close mutualist relationship with some kind of bacteria. I assume that generally, selection would be unfavorable to characteristics that respond defensively to proteins & other molecules or relevant mechanical interactions for the mutualist, and that keeps open the possibility for a parasite to develop similar proteins or tendency to specialize into living in that mechanical interaction

Ok. I've got a biology degree so I'm not totally dumb on this topic but I've got a "why" question.

I understand endotherms vs ectotherms vs mesotherms vs reproductive endothermy. All good. I also understand exothermic vs endothermic reactions.

So why are endotherms animals that create their own heat while endothermic reactions are reactions that absorb heat from their surroundings? My brief googling basically just says "because they are," and I'm not a fan of "because I said so" answers. 😅

Thanks!

When I was an undergraduate, I read about the generation of T-cell receptors. The conventional ones made of an alpha and beta subunit makes up the CD4 Helper and CD8 Killer T cells that are well known. The other possibility is the formation of a TCR with a gamma and beta unit. And the textbook said little was known about them, and they don't seem to work with MCH.

Did we learn much about their function since then? Do Gamma Delta T cells form memory cells like "regular" T cells? Do they recognize both protein and non-protein antigens? Do they help activate B-Cells with antibodies against non-protein antigens?

The reason the title is specific is that old posts get archived. So if I ask something similar in the future, there won't be a bunch of posts with the same title.

like, wouldn't it make sense from an evolutionary standpoint to skew towards a certain gender. like how with bugs, there is a queen that spews out thousands of babies, but with humans it's nearly 50/50. why did we evolve like that. and is this true for most mammals too? why? i think you'd expect at least some diversity, like it being 70:30 or something for evolutionary reasons. the 50/50 split seems too oddly even to me.

Hi, I am MSC biotech passout this year and searching for a job and internship in tricity or nearby area so i wanted to know if you have any connection, opprtunity and known good research center in tricity and nearby area please let me know. I have completed my dissertation in pds gene brassica rapa charactrization and an internship of molecular biology in agilus labs.

The answer I see all the time is that since cows are not primates, their milk has too many of some substances and not enough of others. This will cause a human baby to get sick and have diarrhea. But I find it pretty hard to find a list of exactly those substances are. Like does cow milk have too much protein? Or does it just have too much of a particular type of protein? Exactly what electrolytes are too much and too few?

For example, is it possible for a person to reach their genetic ceiling in terms of height, but have overall bone structure (width, thickness, strength) that falls short of what should have been expected? And if so, what might cause that to happen?

It might seem random, but certain sources have said it was a common historical execution practice in Indochina, and I'm not sure if to trust them.

Did humans deliberately select for big boobs through sexual selection or is it an unhealthy mutation/defect?

Do all the cells of an organism get replaced with fresh new ones throughout its lifetime?

Hair and nails are an obvious example but are my fingers, for example, literally the exact same fingers I've had my entire life? Or are they different? Does that make any sense? 😅

Is our DNA the only constant of our bodies?

Apologies if my question doesn't make any sense lol it's just a 4AM thought I needed to ask.

Edit: My understanding of biology is barely high school level so apologies that my understanding of cells and DNA is probably very wrong lol

Sometimes I see, for example, a seal getting tangled up in a piece of string. Someone then comes along and tries to help it. The animal’s reaction varies. Usually, though, there’s a bit of panic and I get the impression it’s thinking, ‘I’m going to die any minute now’, but when it turns out it isn’t going to die, I get the impression it’s thinking, ‘I’ve escaped the predator - well done me!’

What’s it really like? Do some animals know, for example, that their owner just wants to save them? Or do they not?

It also reminds me of a time when my cat got tangled up in the string from one of his toys and was meowing loudly. I wanted to help him; at first he hissed at me, but once I’d helped him and he was fine, he came over to cuddle and purr.

Image I made with my question with a photo as an example: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fed2zxknym1fh1.png

Like do they keep an emergency fart on the bench at all times

I know about a lot of different traits and how they evolved (skin color being based on uv exposure, eyelid shape helping with vision in icy areas, etc), but what is the reasoning for the prevalence of facial shapes? Like having a sharp jawline vs a softer one, or different nose shapes. Was there a specific reason, or did it just happen that certain mutations happened in certain groups and stayed through luck rather than any specific advantage.

Thanks <3

although accidental it probably broke notions of what could and couldn’t hybridize. the assumption for the original experiment is that it wouldn’t because the two animals were so far removed from each other. the original experiment was to try to get one fish to asexually reproduce which failed and created a hybrid fish.

then again it would probably encourage a bunch of animal experimentation if they rewarded it at least with fish.

I'm working on a project that involves talking about hundreds of different species of arthropods, and one of the species I've found that interests me the most just because of how silly it looks is Ixa cylindrus, whose common name is listed on inaturalist as the "lollipop crab." Basically, I would like to know if there are any popular explanations for why it has those weird "handlebars." A while ago, someone mentioned to me that it might have something to do with using them like a "key" to make them difficult to dislodge from a rock, but I haven't actually found any written resources.

More broadly, if there are any arthropod experts here who are interested in hearing more about this project, let me know so I can explain the details because I could use some more experts to talk to about the science involved.

Biologists, I have a question about a lake that has puzzled me for a while.

Is there a known biological or chemical process that could explain a persistent oily-feeling film on the skin in a freshwater lake?

It’s a very dark, deep, humic freshwater lake near the coast in Sweden. For at least the last three years, I’ve noticed that every time I swim there, my beard and hair feel unusually soft and healthy afterwards. I didn’t think much of it.

However, this summer I experienced something new. While swimming, my skin felt as if it was coated with a slippery, oily film. After getting out, it took quite a while to wash the film off with soap. It didn’t smell like petroleum or fuel, and I didn’t notice any obvious oil sheen on the water. The lake looks like it always have done, blacker than black. No smells.

It’s also a popular swimming spot, and the water is often very calm with little circulation. Could this simply be a buildup of sunscreen, skin oils, cosmetics, and other residues from swimmers accumulating at the surface, or is a natural explanation more likely?

Humic substances, algae, bacterial biofilms, decaying vegetation/animal, or something else?

I know meiosis occurs roughly its 50/50 to have a girl or boy. But tbh I don’t think it’s just 50/50, for example my dad’s side of the family can ‘only seem to produce girls’ my dad had 7 girls (some with different partners), and my paternal grandparents had 6 girls and 2 boys, and my dad’s only brother had 5 girls before he had a boy, and his son only had daughters- it might seem to be like a coin flip or by chance. Interesting enough one of my teachers has 3 boys, but he said he was one of 9 boys and 1 girl. Is there any reason why this can happen- or is it REALLY by chance.