Photo by Krissy Venosdale.

Four and a half billion years is a hard number to digest. That’s the age of the Earth, and a lot has happened in that time. The geologic record contains dramatic climate swings, the formation of entire continents, the proliferation of new species -- as well as mass extinctions. But no matter what has happened in the past, life goes on. Well, in the case of mass extinctions, at least some life does ...

To help people get their heads around our role in all this, geologists use the analogy of a clock: If you compress all of the Earth's history into a single day, humans do not show up on the scene until a minute before midnight.

Happy Monday.

Photo by Chris Johnson.

What are fish thinking when they change genders?

When Burt's Bees invited me to this press event, they probably didn't expect Isabella Rossellini to be the one asking questions, much less that one. Or for her to go on and note that gender assignation is largely a human construct. And to then express curiosity about what the process is like from the fish's perspective.

Sitting next to Rossellini, holding my notebook, I'm not really sure how to answer. After a pause, undeterred, she explains that fish are less interesting to play than insects because "sometimes they spawn, but that is it."

Luckily for her, we were there to talk about insects -- namely, bees -- and sitting with people who could answer the trickier questions she raised: for example, how scientists test for neonicotinoids, a pesticide that may impact bee navigation. ("Do they take the hives? … Do they feed them?" The answers were unknown.)

Rossellini has created an unusual niche for herself. Her series for the Sundance Channel, Green Porno, introduced Americans to the exotic, alarming mating rituals of flies, snails, and praying mantises -- with herself starring as each of the creatures. She enjoys the roles primarily because of the eccentricities of behavior, because of the tiny nuanced details that she likes to try and get right. And, clearly, because it is a topic about which she's deeply curious and fascinated to learn.

Photo by blair 25.

North American black bears have the largest relative brain size of all carnivores, and apparently they are capable of using that brain power to count. Scientists tested three bears on their ability to look at groups of dots and identify whether one group had fewer or more dots than another. (Two bears were looking for "fewer," and the other was looking for "more.") Turns out, they could tell the difference, which means they can count, or anyway do some bear-brain counting-like thing. It’s not like they understand what a “five” is, but they know how many of things there are.

Giving children names is exciting and all, but it is important to consider how they will feel when their name is shouted on the playground. But not so with species! You can name those suckers whatever you want and they will be none the wiser. The Guardian is holding a contest that lets readers indulge in this pleasure by coming up with common names for 10 British species. Past contests have yield such gems as "hotlips" for this labial-looking fungus and "sea piglet shrimp" for this fella.

This year the species on hand are mostly brown. The list includes not one but two sea slugs and lots of bugs. It is actually a travesty that Grist did not think of this idea first, because we are confident that Grist readers can come up with way funnier (and punnier) names than Guardian readers can. (Although, we admit, hotlips may be the best name for a fungus, ever.) We want to see at least one Grist reader's name up in lights on the internet, so get to species-namin’! Here, from the Guardian, are helpful tips:

• Try to incorporate some combination of appearance, natural history, or location. For example, the species' color or feeding habits

• Humor, word play, and cultural references are good when relevant, and names do not need to be direct Latin translations

• Names should ideally consist of two names, not including the taxonomic group name, for example beetle, lichen, shrimp (so three words in total). A good case needs to be made for longer ones

Let's practice on this sea slug, the Akera bullata, shall we? 

Still from an animation of projected ocean acidity.

One of the lesser-known but still widely feared effects of an atmosphere chock-full of carbon dioxide is that it makes the oceans more acidic. The process, as described by Science magazine:

About one-third of the carbon dioxide (CO2) humans pump into the atmosphere eventually diffuses into the surface layer of the ocean. There, it reacts with water to create carbonic acid and release positively charged hydrogen ions that increase the acidity of the ocean. Since preindustrial times, ocean acidity has increased by 30%. By 2100, ocean acidity is expected to rise by as much as another 150%.

The level of acidity at the surface could reach pH levels of about 7.7 by 2050. Contrary to our enticingly misleading headline, this is not nearly acidic enough to melt anyone's toes; it's still less acidic than distilled water. (And, besides, dissolving body parts in acid takes a long time.)

Photo by Xinhua.

These polar bear cubs, born and raised at Tianjin Haichang Polar Ocean Park in China, were so tiny and frail at birth that they weren't expected to survive. Keepers whisked them into an incubator, and have been caring for them around the clock since then. But at 100 days old, the babies are now healthy and playful and super, SUPER cute.

In Urban Dictionary, the fourth definition of "cute" is "pygmy rabbit." Or actually, it’s probably some gross made-up sex act, but it SHOULD be “pygmy rabbit.” Just look at this thing!

It fits into the palm of a human hand!

But it has also been disappearing from its habitat in Washington State. Coyotes, badgers, weasels, and big bad birds chow down on these little suckers, because they are small, vulnerable, and (we're assuming) delicious.

Despite the best attempts of scientists to prompt the rabbits to breed in captivity, the bunnies were just not doing their bunny thing. So instead, the state's Department of Fish and Wildlife is breeding them in their natural habitat. The scientists pen in a few acres, keep the bad coyotes out, and let the bunnies in.

Get out of there, giraffe! You are not Olympic gold medalist Michael Phelps! You are a giraffe!

The theme of the new installation at the Reiman Gardens, a massive public garden at Iowa State University, is "Nature Connects." That usually means something about the complex interdependency of the ecological network and blah blah hippie stuff, but in this case it means nature literally snaps together out of LEGO bricks. And also blah blah hippie stuff as well.