1

Balance - Long-necked birds move their head forward or back during flight to counterbalance their bodies. Create a creature with a large adjustable counterweight.

2

Respiration

The Skate comes from an order (Batoidea -- literally, bat-like fish) which has its gills on the bottom of its body. However, skates spend much of their time on the sandy floor of their habitat. Rather than moving the gills, evolution created spiracles on the top, just behind the eyes (since there was already a convenient eye hole).

Most birds have true circular breathing, in the sense that the air exits their lungs along a different path than it enters. In order to do this, the air actually passes through hollow sections the bird's bones on its way back to the nostrils.

Create a creature with a convoluted path for air.

3

Transparent

In the open ocean, there is rarely anywhere to take cover. In order to avoid detection, many species choose to be nearly completely transparent.

Meanwhile, on land,  the Glass Frog has a transparent body, but many of its organs haven't figuret out how to be transparent. So the organs have migrated downwards, as far as possible from the frog's back, to reduce their visibility through the transparent but foggy flesh.

Back in the ocean, the Barrel-eye fish has delved to depths where its ancestor's eyes would have been useless in the low light. Rather than simply enlarging the eyes, its entire head has become transparent and the eyes receded inwards while becoming huge, so that they can collect enough light and look in any direction.

Tortoise shell beetles have transparent wing covers, but rather than hiding anything, the purpose is to show off markings on their body below, which warn predators of their toxicity. Why not put the markings on the wing covers? Well, evolution just doesn't do it that way.

Create a creature with complete or partial transparency.

4

Cooling

A common adaptation for cooling is large surface area - rabbits use long ears and elephants flap their big floppy ears.

Contact with the air isn't the only way; many animals will lie low in the dirt to let the ground soak up their body heat.

But simply avoiding the heat can be equally important. Desert-dwelling squirrels use their poofy tails to shade themselves from the sun.

Another option is to simply accept a higher body temperature. On Earth, land creatures (ants) have seemingly managed up to 52 degrees C, while water-dwelling arthropods have managed body temperatures up to 50 degrees C. (The ants are most likely doing something to keep their core temperature below their average body temperature.) However, a species adapting to a high body temperature gives many subtle things up in return, since they must use a different set of chemical reactions for their metabolism than their ancestors. They are often small, because of an odd tradeoff -- their maturation becomes faster but their body growth cannot keep up.

Create a creature which is adapted to the heat.

5

Low biomass environment

In most species, males have a lower cost of reproduction than females, and frequently this means they will seek out more mates. However, in the deep sea, population is so sparse that a male may only ever encounter one female; so instead of seeking out more mates, he had better stay close to the one he's got. This reaches its extreme in the anglerfish, where the males literally merge with the female, dissolving most of their anatomy to become nothing but a new bodily organ.

Deep sea creatures such as sleeper sharks adapt to the low biomass of their environment by quietly drifting with a slow metabolism until they encounter prey.

Create a creature adapted to an environment where it encounters practically nothing for months or years.

6

Being seen while remaining unseen

There are jumping spiders with bright red markings despite the fact that their own species cannot see the color red. This is because of conflicting pressure: males want to have high contrast markings to catch the eyes of females, but they want to remain invisible to birds. The red color looks like black to fellow jumping spiders, forming good contrast with the white, grey and ultraviolet colors used elsewhere. But the red looks similar to brown tree bark to birds overhead.

 Create a creature which is showy to some while being hard to spot for others.

7

Running

In order to sprint at great speed, the cheetah has a lightweight, almost fragile body, and the bones at its joints are extended or exaggerated in order to allow plenty of muscle to attach there. Meanwhile, humans take a different approach, and accomplish endurance running with an efficient bipedal stance and hairless, sweaty skin.

Create a creature adapted for high speed travel.

8

Antagonism to mutualism

When the ancestors of the first grasses discovered their more efficient means of photosynthesis, they quickly spread across the open spaces of the world. However, herbivores came close behind, eager to munch up the new greenery. For this reason, grass has adapted to embed tiny grains of rock in itself, which served as a deterrent, and would quickly destroy the teeth of herbivores feeding on grass, leading to starvation. Herbivores of course adapted, gaining teeth which would constantly grow as they were worn down.

The relationship today is a mutualist one. Grasses have their growing points close to their roots where grazers don't damage them, and actually benefit from the grazing; and grazing animals now of course depend on the hard minerals in the grass to keep their teeth in shape.

Create a creature in which an initially antagonistic adaptation has become mutualistic.

9

Bird Brain

Birds approaching an object will often give both eyes a good look at the new object. This is because the two sides of the visual lobe are not very good at communicating, and if both sides see an object then both halves of the brain get a chance to react. Pigeons in particular have been found to have six different eye areas which they try to let have a good look.

When an octopus is enjoying a meal, it will pass the food from arm to arm so that each of its eight arms, which have a degree of independent intelligence, all get a good taste before the food enters the mouth.

Create a creature whose nervous system communicates and coordinates using the outside world.

10

Social Pigmentation

Humans and certain crabs have coloration on their eyes to make it clear to one another where they're looking. 

Make a creature with a movement or body part enhanced for social visibility.

11

Building

Many creatures simply pick up and place building materials. However, termites and paper wasps swallow and then regurgitate building materials; spiders secrete them.

Make a creature which builds.

12

Centaurization

Praying mantids have adapted their front limbs from locomotion to catching prey.

Skates have adapted a pair of fins to "walk" on the seafloor.

The lower jaws which most vertebrates have, are adapted from an ancestral pair of limbs.

Create a creature which has adapted a pair of its limbs for another purpose.