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Birds have a body part known as the nicitating membrane otherwise known as the "third eyelid". This part has become vestigial in humans, where it remains as the plica semilunaris. This image of a masked lapwing clearly shows its nicitating membrane in action, where it covers the eye in a horizontal motion. This is analogous to blinking in humans, and the ...


7

Males of the carnivorous Jackson's chameleon (Trioceros jacksonii) have three hornlike structures on their heads (also found in a couple of related species). From what I know, these are true horns, which means that they are pointed keratin-covered protrusions that have a core of living bone, see e.g. this website from Toronto Zoo (this page also claims that ...


4

I think the lack of sea ice coverage would point you somewhere- even with the maximum sea ice coverage picture, the SW corner of Greenland has next to none, which may impact the carrying capacity for both bears and prey animals on that narrow strip of land between the ice cap and the sea- less space and less things to hunt, less ways to get around, etc. And ...


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Cucumber contains a compound called trans-2-nonenal (reference 1 and reference 2) that repels insects. This particular compound (reference) has can also be used in insecticide foams for repelling ants (reference)


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My best guess would be Trematoda which is a fluke worm that infects mollusk. I would think this is the larval stage of cercaria which is free swimming and develops in the mollusk and then moves on to infect others. Here are some different images of a cercaria: In this YouTube video you will see what is known as a "Rat King" which is just a ball ...


4

I didn't watch the video so I don't know if this was mentioned. Butterflies will exhibit a behavior called mud puddling which occurs mainly with male butterflies [1]. Puddling is when butterflies seek out moist surfaces in order to consume the fluid. Butterflies will puddle in soil, dung, carrion (rotting flesh/meat), etc. Boggs and Jackson claim that ...


2

Welcome to Biology.SE Insects don't "like" being on their back because they can't get back to their legs and they therefore get stuck somewhere where they can gently wait for death to come. Not all insects are unable to switch back on their legs but some can't do that (or can hardly do that). The reasons for which many insects are not able to get back on ...


2

This is really google qestion. For some blood types, evolution and environmental selective pressures are clearly important for their persistence. For example, the Duffy blood type includes a receptor that allows certain types of malarial parasites to enter the red cell. Thus, in some malarial areas of Africa, populations with Duffy-negative blood ...


2

Animals living in colder climate / environment are larger because this way they have better body surface / volume (mass) ration thus they're more resistant to cold. Animals living in warmer areas are smaller thus they have larger body surface compared to their volume(mass) to dissipate heat easier. Check this wiki page for more details.


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I would say that the left part of the picture depicts 2 stages of the development of cysticercoid, while the right part shows the consecutive stages in the development of cysticercus. These two parts represent different species of tapeworms in the same stage of their developments.


1

As far as alive carnivorous land animals go, there are non. But let's search in the sea: Narwhal (Monodon monoceros) courtsey: http://i.huffpost.com/gen/1625488/images/o-NARWHAL-facebook.jpg Longhorn cowfish(Lactoria cornuta) courtesy: Wikipedia They are omnivourus and feed mainly on microorganism. There are loads of sites claiming them horned ...


1

Birds, like amphibians, have a third eyelid (the nicitating membrane) that helps them keeps their eyes moistened and allows them to better visualize at high speeds (or, for amphibians, underwater). The glands in birds' eyes allow them to secrete a fluid that is more resistant to evaporation than tears. The membrane also acts as a 'windshield wiper,' with ...


1

They probably don't know and probably don't need to. They tend to run away from potential danger and predators in the same evolution environment because those who don't run away will have fewer offsprings that exhibit similar behaviors. If an animal suddenly sees a predator that his ancestor has never seen before, then it may not run away from it, to its ...


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Scorpions are immune to their own venom (reference) as has been said in some studies as well (reference) But some other studies and eye witness accounts have referred to the contrary. in an experiment a scorpion, Bulteus australis, was killed by an injection of the same venom as its own (reference). So, it should be safe to say that there is a very ...


1

To answer your first question; it is not necessary that every trait have an evolutionary advantage. Neutral traits can persist in the population without having any adaptive value, or they can persist as a byproduct of another trait that does have adaptive value. Even a slightly detrimental trait can become fixed due to genetic drift. Take a look at this ...



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