Many animals are considered useful to humans because they provide food or other products and have economic value, such as bees that provide honey, wax and pollen.
While others are considered harmful because they cause harm, and can even affect human health, such as insects that reach plantations or transmit diseases.
Understand more about the true usefulness of animals!
Harmful Why? Useful for Whom?
The invertebrates are all that have no spine or vertebrae or skull.
Most of the animals we know are invertebrates: insects, crustaceans, spiders, scorpions, sponges, jellyfish, worms, starfish, among others.
The insects are those with the greatest diversity of all the animals. In the following figures, an example of bed bug (left), which causes skin problems and a termite in detail (right).
It is important to note that animals only attack humans when they feel threatened, it is a form of defense. If the human being occupies the territory of an animal he can attack it to defend its space.
For example, if a person is in the woods and accidentally steps on or touches a spider or scorpion, they are likely to be bitten, this is part of the animal’s survival instinct. Therefore, it is advisable to know and respect the animal’s habits, like any poisonous or poisonous animal, avoiding accidents.
See the figures below: a black widow spider (left), details of the eyes of a crab (center) and a scorpion (right).
Someone would say, what about parasites ?
In fact, the parasites cause damage to their hosts, but most of the time they are not so big that they deserve concern.
They are usually already well adapted to each other, if the host dies the parasite will die and, thus, the tendency is for this relationship to become balanced over the generations, producing a relationship called co-adaptation.
After all, a person is not likely to die from having lice inhabiting his head, and there are many ways to eliminate it.
Among the parasites of the human being, we highlight the lice, terns and flatworms (tapeworms and schistosomes) and nematodes or nematodes (worms, hookworms, geographic animals, among others).
Other invertebrates can transmit diseases that deserve real care, as in the case of the dengue mosquito .
Also read about the diseases: schistosomiasis , scabies or scabies and malaria.
Animals are very useful in nature
On the other hand, all animals are useful if we think about food chains. Even those so-called harmful, the most disgusting insect considered to be harmful to humans can be the precious food of a bird, or a frog.
If it is exterminated so as not to affect man, it will harm those who feed on it and so on, it will end up affecting the whole balance of nature.
An example is the ladybug and aphids, they attack plants and are considered harmful, but in nature they are food for the ladybug. That’s right, the ladybug is a carnivore and a predator of aphid herbivores! (See the photo on the left, and the aphids in detail on the plant on the right.)
In the food webs , the human species is at the top, so we are the predators!
Many animals (both invertebrates and vertebrates) that are classified as useful, as they serve as food or offer products appreciated by humans, have suffered or suffer from mistreatment, some are threatened with extinction and others have already been extinct.
Risks to Ecological Balance
It is important to reflect on the classification of animals as useful or harmful, understanding that with this there may be misconceptions about a “harmful” animal and excessive valuation and consequent exploitation of “useful” animals, promoting prejudices about certain animals and risks to others.
In addition to deforestation and habitat destruction, poaching and animal trafficking, environmental crimes continue to happen indiscriminately, disrespecting the natural balance and threatening many species.
An example of this problem are some species of crab spiders, which are neither aggressive nor poisonous and are very popular in Europe as pets.
There are 2 endangered species found in Bahia, one Avicularia gamba is classified as critical. Already diversipes Avicularia ( photo above left ) is in danger (according to data from 2014 the Ministry of Environment and ICMBio), and are endemic to Brazil, that is, there are only here.
While in nature there is no classification or distinction, there are relationships between species that allow a balance, which is often hampered by human action.