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No, fish scales are dermal (= formed in derma) bones like skull roof bones. Scales in reptiles are formed by epidermis and are made primarily of protein (from keratinocytes), being similar in derivation to hair, feather and nails. On the other hand, in reptiles one must differentiate between scales and osteoderms (= scutes). Scutes are widespread among ...


4

The idea you're talking about is Panspermia -- the theory that life on planet Earth originated somewhere else and began here during some sort of fertilizing event. From a biological point of view, all known life (with the exception of some very odd and unique species of single-celled organisms that are difficult to categorize) utilizes the predictable ...


3

Humans and other animals have lots of innate behaviors that are not learned from observation, i.e. behaviors that are hard-wired into our nervous system, and this is one of them. Suckling reflexes in mammals and the Moro reflex is human babies (which we grow out of) are other simple examples. The stretching behaviours you are referring to are usually ...


2

Don't know whether it was ever investigated, but I'm pretty sure, that frogs can in principle swim upside down (e.g. when escaping from predator), but they normally do not do it. One example of alternative swimming styles in animals is provided by some munnopsidid isopod crustaceans. Several genera are pelagic and have very elongated forelegs equipped with ...


2

From what I can tell, marine mammals can't dynamically control buoyancy during a dive. They ease the beginning of the dive by starting with a small lung volume to reduce buoyancy. Pinnipeds like seals do this by exhaling half their breath before diving. Deep-diving whales actually breathe in before diving, but their lungs are small relative to body size ...


2

The most common active ingredient in insect repellents is N,N-diethyl-3-methylbenzamide (other name: N,N-diethyl-m-toluamide; abbreviated DEET). It provides protection against mosquitoes and many other insects. After various interesting hypotheses, it is currently assumed that mosquitoes simply smell DEET directly and avoid it.[1]


1

Although your plastic bag tears are most likely due to light damage as @Chris mentioned above, there is a type of ant that chews its way through plastic, rubber and other manufactured polymers: Monomorium pharaonis, the Pharaoh ant. It is capable of destroying many manufactured materials and is a great example of budding, a method by which new ant ...


1

Yes, creatures can swim different ways. If you drop a frog into water while it is in the ventral up position, it will indeed swim upside down to escape before righting itself, which occurs by rotating while swimming. If the water is too shallow, it will flop and flip before jumping away. Swimming on the surface ventral side up is kind of silly for a frog ...



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