let's get spooky

And yet we still don’t have a dystopian, clone-filled existential nightmare as predicted by The Island, The House of The Scorpion, The Sixth Day, Never Let Me Go, or almost any other film or book featuring cloning humans. In fact, while some people claim that they have cloned humans, it hasn’t been confirmed and human clones may never have been created at all. It’s not likely to happen soon, because cloning people is very difficult, there isn’t much demand, and is illegal in many countries. Photo: Taxidermy mount of Dolly by Toni Barros from São Paulo, Brasil - Hello, Dolly!

This carved ostrich egg is believed to be the oldest depiction of the New World on a globe.

(via:Science Alert)

Admittedly, I am easily won over by all organisms that attract flies with the scent of rotting flesh. But the octopus stinkhorn (Clathrus archeri) also has tentacles, a freaky egg stage, and blackish goop, so it’s my favorite now.

Say “tree bark” and everyone knows what you’re talking about. We learn at an early age that bark is something trees have. But what is bark? What is its purpose and why are there so many different kinds? Indeed, there would seem to be as many different types of bark as there are trees. It can even be used as a diagnostic feature, allowing tree enthusiasts to tease apart what kind of tree they are looking at. Bark is not only fascinating, it serves a serious adaptive purpose as well. To begin to understand bark, we must first look at how it is formed. To start out, bark isn’t a very technical term. Bark isn’t even a single type of tissue. Instead, bark encompasses several different kinds of tissues. If you remember back to Plant Growth 101, you may have heard the word “cambium” get thrown around. Cambium is a layer of actively dividing tissue sandwiched between the xylem and the phloem in the stems and roots of plants. As this layer grows and divides, the inside cells become the xylem whereas the outside cells become the phloem.  Successive divisions produce what is known as secondary phloem. This is where the bark begins. On the outside of this secondary phloem are three rings of tissues collectively referred to as the “periderm.” It is the periderm which is responsible for the distinctive bark patterns we see. As a layer of cells called the “cork cambium” divides, the outer layer becomes cork. These cells die as soon as they are fully developed. This layer is most obvious in smooth bark species such as beech.  Similar to insect growth, however, the growth of the insides of a tree will eventually outpace the bark. When this happens, the periderm begins to split and cracks will begin to appear in the bark. This phenomenon is most readily visible in trees like red oaks. When this starts to happen, cells within the secondary phloem begin to divide. This forms a new periderm underneath the old one. The cumulative result of this results in alternating layers of old periderm old phloem tissue referred to as “rhytidome.“  This gives trees like black cheery their scaly appearance or, if the rhytidome consists of tight layers, the characteristic ridges of white ash and white oak. Essentially, the distribution and growth pattern of the periderm gives the tree is bark characteristics. But why do trees do this? Why is bark there in the first place? The dominant role of bark is protection. Without it, vital vascular tissues risk being damaged and the tree would rapidly loose water. It also protects the tree from pests and pathogens. The cell walls of cork contain high amounts of suberin, a waxy substance that protects against desiccation, insect attack, as well as fungal and bacterial infection. Thick bark can also insulate trees from fire.  Countless aspects of the environment have influenced the evolution of tree bark. In some species such as aspen or sycamore, the trunk and stems function as additional photosynthetic organs. In these species, cork layers aare thin and often flaky. Shedding these thin layers of bark ensures that buildup of mosses, lichens, and other epiphytes doesn’t interfere with photosynthesis. The white substance on paper birch bark not only inhibits fungal growth, it also helps prevent desiccation while at the same time making it distasteful for browsing insects and mammals alike. When you consider all the different roles that bark can play, it is no wonder then that there are so many different kinds. This is only the tip of the ice berg. Entire scientific careers have been devoted to understanding this group of tissues. For now, winter is an excellent time to start noticing bark. Take some time and get to know the trees around you for their bark rather than their leaves. Photo Credits: Eli Sagor (bit.ly/1OTnA8H), Randy McRoberts (bit.ly/1PgzH35), Lotus Johnson (bit.ly/1JyVt1E), SNappa2006 (bit.ly/1TkjHil), and nutmeg66 (bit.ly/1QwyZQ8) Further Reading: http://www.botgard.ucla.edu/html/botanytextbooks/generalbotany/barkfeatures/typesofbark.html http://dendro.cnre.vt.edu/forestbiology/cambium2_no_scene_1.swf http://life9e.sinauer.com/life9e/pages/34/342001.html http://www.botgard.ucla.edu/html/botanytextbooks/generalbotany/barkfeatures/

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William Franklin Dove was a modern Dr. Frankenstein who made live unicorns. Above is his “unibull”, with one massive horn. However, Dove was no mad scientist. He was a respected biologist who studied the nature of horns. Dove theorized that horns don’t grow from the skull, but rather develop separately and grow into it over time. To test his hypothesis, in 1933 Dove took a day-old Ayrshire calf, surgically removed its horn buds, cut them to fit together and implanted them close together. Sure enough, the bull did grow a single, fused horn in the middle of its forehead, covered by a single sheeth of keratin. The bull was able to recognize its single horn and use it as a prow to pass under fences or as a thrusting bayonet in its attacks–thus demonstrating the power of neuroplasticity. Despite its fearsome appearance, Dove’s unibull was reportedly unusually docile.

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Chand Baori - Indian stepwell Abhaneri Rajasthan 800 AD

Another day in the lab 💜

It’s Nature is Awesome Day on Geyser of Awesome! Celebrating naturally occurring amazements of all kinds…

Illustration by Peter Schouten from A Gap in Nature.

Some Western Honeybee news in the National Post (13/10/2015)

Chris A. Whitehouse is a microbiologist and science writer who lives in Maryland.  He writes extensively on emerging infectious diseases of humans and wildlife.