How do mosquitoes locate the source of blood in both humans and animals?

When adult mosquito emerge from the aquatic stage they mate, and the female seeks a mammalian blood meal to obtain protein necessary for the development of her eggs. Mosquitoes are attracted by perspiration, warmth, body odour, carbon dioxide and light. Scientists are still investigating the complexities involved with mosquito-host acceptance and rejection. Some people are highly attractive to mosquito while others are not.

Mosquitoes have specific requirements to satisfy and process many different factors before they feed. Many of the mosquito’s physiological demands are poorly understood and many of the process they use to evaluate potential blood meal hosts remain a mystery. Female mosquitoes use the CO2 we exhale as their primary cue location.

A host seeking mosquito is guided to our skin by following the slip stream of CO2 that exudes from our breath. Once they have landed, they rely on a number of short range attractants to determine if we are an acceptable blood meal host.

Folic acid is one chemical that appears to be particularly important, fragrances from hair sprays, perfumes, deodorants and soap can cover these chemical uses. They can also function to either enhance or repel the host seeking drive. Dark colour captures heat and makes people more attractive. Detergents, fabric softeners, perfumes and body odour can counteract the effects of flour.

How do snakes shed their skin every month?

Skin of snake consists of outer epidermis and inner dermis. The inner dermis (soft, fibrous and pliable) contains pigment cells that give characteristic colour patterns. The outer epidermis Keratinised layer (stratum corneum) made up of horny scales, resists normal wear and tear and protects from injury.

The Keratinised layer is shed sloughed every 60-70 days or earlier or 3-4 times a year. In young ones and some species the rate of casting may be higher or once in a year. The snake, normally hiding just before casting, is lethargic. New epidermis is grown beneath the old skin and secretes a thin layer of fluid between old and new skin.

Shedding parts by opening and secreting the mouth and rubbing it on the surrounding available objects until the old skin under at the edges of the lips begins to split. The process of rubbing continues till the skin is shed in one piece from head to tail or sometimes the skin will break up and come off in pieces.

The skin, turned out like a tight glove being pulled off from hand, is a perfect cast of the snake including eye scales. This process takes nearly half an hour or more. The cast is completely devoid of colour as the pigment cell remain in the dermis is never shed. The shedded skin is transparent and brittle. After casting the snakes become fresh, alert, active and bright. The sloughing indicates growth of snakes and it is affected by factors such as health, environmental temperature and amount of food taken.

Why do humans want to brush their teeths while animals don't want?

Teeths are hard white substances found n the mouth of humans and in many other animals and s used for mastication.Some characteristics like morphology of teeth and food habits warrants brushing of teeth in humans but it is not so in case of animals.

First we will see the adaptation in the teeth of animals, which does not necessary brushing in them. For e.g. the teeth of snake are very thin and sharp and usually curve backward. They function in capturing the prey and not in chewing, for snakes swallow their food whole. The teeth of carnivorous mammals like cats and dogs are more pointed and adapted to cutting and shearing.

The difference in shape of teeth is functional adaptations. The plant cells used as food by herbivores in cellulose cell walls. This necessitates its chewing of food in order to break down he cell walls. Although the teeth come to play, nature of the food is raw, fibrous and no sticky. So brushing is not necessary because it does not cause any probs to the dentition.

By contrast, animal cells in meat are not encased in cell walls and can act upon directly by digestive enzymes. This is the case in carnivores, where chewing is not necessary. Their teeth come to play only when cutting and shearing the prey. This reason for non brushing of teeth in animals. Humans who are omnivores have teeth somewhere between the extremes of specialisation attained by the teeth of carnivores and herbivores.

Tooth brushing in humans is mandatory because of the following reasons: modern refined diet that has ready fermentable carbohydrates which is prone to cause caries, to prevent dental caries and periodontal diseases, to aid in plaque control, to maintain good oral hygiene. Therefore the morphology of teeth in humans necessitates brushing because of soft and sticky diet consumed by modern man. It is also indicated in order to prevent the dental diseases and to maintain hygienic status.