No beavers build dams in lakes all the time. They will either pile a beaver house on the shore or they'll run a straight line across the middle of a skinny part of the lake. I've seen it both ways. You can DM me and I'll send you a Google pic of a lake with beaver dams all over it

Is it possible to distinguish a lone free cancer cell from a healthy functioning one under a microscope?

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Thanks for all the replies! This lake I'm referring to is not beaver made, it's a huge man made lake that surrounds much of a major city.

I was stoked to see a beaver there but confused because, obviously, i don't know a lot about them, and didn't know why they'd be in a lake, eating lily pads.

Well, turns out, they probably built some posh lodge because the sound of running water isn't triggering their rage inspired damming instinct!!

Edit: words

Occasionally you still see some big birds (ostriches or emus) on farms.

More than likely they dammed up a river or creek that turned into a lake.

As others have said, they don't make dams in lakes, but they do make "lodges" in lakes. The purpose of the dam is to have deep enough water so they can have an underwater entrance to their lodge. In a lake they don't need a dam to do that.

I just want to say, that's such a wholesome, interesting, and useful career goal. Beavers are cool creatures, and very important for the environments they change/create. I wish you luck!

Stains for antibodies associated with various cancers also stain black after Immunohistochemistry stains and can give this impression.

Especially considering that most finished stains in Pathology are very colorful.

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Historically reptiles used to mean all sprawling or semi-erect amniotes. So all amniotes besides mammals and dinosaurs (which are erect)

Some people want it to be a monophyletic taxon, but all the relevant ones are already taken. They could have chosen that reptile means amniotes, but they choose sauropsids. In practice, reptile isn't used as a monophyletic taxon. When it is used, most people mean the historical definition.

Amniotes and sauropsids are already clear terms and don't need to be replaced.

I work in cancer research where we inject different types of cancer cells into a mouse to grow. When extracting the tumor, almost all of them just look like a squishy tan blob. Some are darker or lighter depending on the type of cells and angiogenesis (ability to grow blood vessels from existing vasculature).

They don't actually look like normal cells. Benign tumors do. Cancerous tumors, while still the same color as the tissue they originated from, usually exhibit a bunch of characteristics that are easy to see on a sample under a microscope. That's why biopsies are a common part of cancer diagnosis. After a surgery, the removed tumors borders are examined. There should be healthy cells on all edges to ensure the entire cancerous mass was removed. This might even be done before the patient is closed back up! Cancer cells are a variety of sizes and shapes rather than uniform; they are immature, often looking like cells from an embryo rather than a person who has been born; they lose their specialized features that allow them to do whatever their function is; they have multiple large nuclei (the part of the cell that holds DNA,) and that DNA is tangled; they contain less fluid; they have more blood supply growing, and they aren't attached properly to each other or surrounding tissues.

And skin cancer might appear darker because your skin is made of different types of cells. If the pigment producing cell (melanocyte, the cell that gives your skin it's color) is the cancerous one, you get a bunch of pigmented cells clustered together and it's darker than the surrounding skin cells that don't make pigment.

Many kinds of cancerous tumors appear whiter than healthy tissue on the inside of the mass. Some bloody or necrotic masses can appear black but that’s not really the cancerous cells causing the color. In general most cancerous cells look like an off-white color

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Just fyi, this was most likely because of certain dyes that are used in patholgy labs. Cells by themselves are colourless unless they contain specific pigments - like black-ish melanocytes.

https://en.m.wikipedia.org/wiki/H%26E_stain

Hope that cancer is gone now.

Grossly (with your bare eyes) tumours are usually white/yellow and hard compared to the surrounding tissue. There is obviously lots of variation but generally that’s what we see in pathology. Skin specifically has more colour variation than others (colon, breast, oral).

That's exactly what it is. It just so happens that creates dams, which is good for them, so they evolved to hate the burbling water and want to plug it up.

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Thanks for the info