What type of aliens are there

IUCN's work on invasive alien species. European Commission: Invasive Alien Species. European Network on Invasive Alien Species. Follow us. Procurement Careers Terms and conditions Legal. The problem is that plants and animals have been in an evolutionary war for millennia. We inherit the outcome of that war. Teeth were necessary to eat plants that became more fibrous, an evolutionary reaction to being eaten. There are other ways to sheer off plant food, such as what birds do.

They 'chew' in their gizzards. Most certainly. Other means of locomotion will be relatively slow and be relegated to armored animals and of those living in holes. Neither of these lifestyles will lead naturally to greater intelligence. How many legs? In our case, we adapted the forelegs for manipulation from animals with four legs. No land animals with endoskeletons have more legs.

The implication is that aliens with two legs are more likely than those with four. Something else truly alien? The skin covering could be anything that makes sense. Real feathers are not so likely. Because feathers are used for flight, brains will be small. Scales are unlikely because they are particularly well-adapted for ectotherms, although a scaly sort of skin might be possible. Fur versus hair is hard to sort out because of my inherent bias.

Fur has good reasons for being that are not related to intelligence. If furry, our aliens probably have short fur. If you define head as a bony enclosure for the brain as well as the location for eyes, nose, and mouth, then it's likely. The nose could be located above or below the mouth.

Above works better for swimming, but that's not a strict evolutionary requirement. Not at all necessary. Useful to swivel the head, but you can imagine other ways to look around.

It's an annoying place for big cats to grab and strangle you with their powerful mouths. You must have something with which to manipulate things. Tentacles are unlikely because of their inability to perform fine manipulation. They usually have suckers on them and a very different purpose than toolmaking. The number of joints could be greater, and the direction of bend could be different. You must have a way to grab tightly and a way to pick up small objects and twist and turn them.

Two fingers are probably too few. Five is overkill. Three or four as cartoon characters have is about right. Our three joints in our fingers is about right.

One would not do. Two, as with our thumbs, is unlikely. It seems strange to think the truly alien would look anything at all like us. And yet there are examples of parallel evolution in nature: the eye of the octopus being identical to that of a human being a famous one.

Some speculate that an alien evolved to have a civilization similar to ours would have a similar form. Octopuses and squids exhibit startlingly intelligent responses and learning, and the form of their bodies is designed for an environment alien to our own. Tentacles and large brains seems to be a fantastic form for low-gravity or aquatic environments. Creatures that may communicate by flashing colors across their skin. Science fiction has a long history of exploring hard-to-understand tentacled horrors.

The idea of biology and evolution already using cogs leads one to wonder what else might exist. Minds that evolved silicon circuitry through natural selection? Steampunk, radiation-powered life forms that we couldn't even approach? Thought experiments can get rather mind-boggling. Nature always surprises. We already struggle to keep patient enough to understand other cultures and differences within our own human cultures. Dolphins, octopuses, elephants—these all seem to be higher-order thinkers, yet we cannot communicate well with them nor do we particularly share the planet well.

What will an alien encounter be like? How will their actions seem? And their actions will depend a great deal on the environs they come from, and the nature of their groups. Are they solitary? Or prefer herds or small bands? What would be the mind of an intelligent predator who normally lives alone?

If we do find other life, I have to assume that it would hint that a great deal of life is possible. We may encounter all of the above. Creatures like us, and yet so different from us we can barely understand them.

It might be a plethora of minds and body types, much like the world is filled now with a wide variety of intelligences and forms. It might be quite overwhelming So it would certainly be reasonable to guess that the technological lifetime of societies is 10, years, not Choosing the larger number increases the tally of inhabited worlds by times.

Earth-like planets can spontaneously generate living organisms, and some worlds will eventually spawn an intelligent species. But surely not all such worlds will do so. A second premise in the Nottingham paper is equally astonishing: Namely, that every Earth-size planet with a temperate climate will produce life, and after about 4 or 5 billion years, intelligent life will appear. Now, of course, most scientists agree with the obvious: that Earth-like planets can spontaneously generate living organisms, and some worlds will eventually spawn an intelligent species.

The Nottingham paper has drawn a lot of attention because it claims that the number of inhabited worlds is likely paltry. But, in fact, by making your own assumptions you can derive just about any estimate for the number of intelligent cosmic species. For myself, I figure that an absolute minimum would be 70, the number that managed to bag speaking roles in "Star Trek. IE 11 is not supported. For an optimal experience visit our site on another browser.