Evolution
The concept of evolution refers to the change of condition that gives rise to a new form of a determined object of study or analysis . It is important to note that evolutions are gradual processes , changes that occur gradually and that can only be observed over time .
The term evolution has its most basic use in the field of biology , particularly to refer to the emergence of the species that inhabit the world, but it also has corresponding uses in other sciences .
Biological evolution is produced by the modification of the genetic composition , derived from the need to adapt to the environment where living beings live . All natural species have evolved, and those that have not been able to carry out these processes have become extinct.
This evolutionary process began in the primitive sea , where the first life was generated , and from that the molecular compositions were altering, preserving certain similarities that allow us to account for the complete evolutionary chain.
What are the theories that explain evolution?
Man has faced this evolution in different ways to explain it in a way that fits into his interpretation of the world. Let’s see some theories that have had greater or lesser acceptance within societies :
- Theory of acquired characteristics . Jean-Baptiste Lamarck assumed that the characteristics acquired throughout the existence of an individual would also be characteristics of his offspring, giving a very important role to what we know as heredity. The habit , as in the case of the first giraffes craning their necks to get food , ends up predominating in the entire species.
- Theory of mutations. Gregor Mendel proposed a very strong theory regarding this inheritance, differentiating recessive genes from dominant ones. This is how the theory of mutations began to gain strength . This term refers to the permanent changes in the genetic material of a cell , which can occur due to the action of mutagenic agents or due to errors in the copying of the genetic material during cell division processes. It was believed that mutations introduce new species, being the quintessential source of evolution.
- religion . Religion has for centuries taken a stand against all evolutionary theories. The first answer has always been creationism, the direct interpretation of the Bible that explains the origin of species through God or a similar figure who creates them. With the passage of time and the increasingly strong evidence of evolution, religious scientists moved away from this categorically creationist doctrine.
- Darwin’s Theory of Evolution . The theory that obtained the most consensus within the scientific community was that of Charles Darwin, who speaks of natural selection among living organisms , since most fail to survive. The consequences of this selection are adaptation and diversification, and a constant struggle of the species in which only the strongest will survive. This position was later complemented by Wallace, who brought up the question of the dynamics of these changes and of the common ancestor of all species. The combination of these two positions is undoubtedly the one agreed upon by the majority of the scientific community today, due to how complete it is in explaining the processes that all species went through.
In the case of the human race, there is an evolutionary chain that begins, it is believed, more than 5 million years ago with Australopithecus, and a series of hominids that gradually abandon the characteristics of the monkey and take on those of the human being ( species known as Homo sapiens sapiens).
The term was extrapolated and evolution is spoken of to refer to other things that are not limited to the biological , including physics ( which describes the movement of an object as the evolution in time of its place in space ) . , psychology (which believes that evolution is the change in behavior or attitude ) or epistemology (which attributes the concept to transformations in theories or ideas).
Types of evolution
Divergent evolution or adaptive radiation
It is a species that over time separates into two. For example, a flock of migrating birds, heading for warmer weather, breaks up in a storm. Half of the flock continues to the original destination, while the other half land on a new island and decide to stay. Over time, members of the second group will develop characteristics that allow them to better survive on the island and become a different species than their ancestors, who were initially separated from the larger herd. What was once one species has now been split into two. For example, the finches of the Galapagos islands have evolved different beaks in ways to take advantage of the different types of food available on different islands.
convergent evolution
When the same adaptations evolve independently, under similar selection pressures. For example, flying insects, birds, and bats have evolved the ability to fly, but independently of each other.
coevolution Coevolution
occurs when two species or groups of species mutually affect each other, causing their evolution together. This happens when one adapts to changes in the other. Coevolution includes symbiotic relationships that are associations between species and may or may not be beneficial, for example:
MUTUALISM
In mutualism, in this relationship, each organism benefits from the activity of the other (flowers and pollinators, one disperses pollen, the other feeds on it or on the nectar of the flower; like bees).
PARASITISM
In this relationship, one species (the parasite) benefits at the expense of another (the host). The parasites can be seen with the naked eye (macroparasites) such as intestinal worms, mistletoe in plants, or lice and fleas in animals and humans; or they can be very small (microparasites) that an instrument is necessary that allows us to observe them like a microscope such as: viruses, bacteria, fungi or protozoa (amoebas).
COMMENSALISM
It is the relationship between two organisms in which one benefits without harming the other, example: remoras (fish) that adhere with a structure on their head, to the body of other larger fish, generally sharks, wait for the big fish to marry and eat the residue they leave behind.
AMENSALISM
Amensalism is an interaction in which one organism inflicts harm on another organism without any cost or benefit (Willey, Sherwood, & Woolverton, 2009). In this relationship there are two types of amensalism, competition and antibiosis. Competition is when a larger or stronger organism deprives a smaller or weaker one of some kind of resource. For example: a sapling of a plant growing under the shade of a mature tree. The mature tree can rob the sapling of the light necessary for its sustenance, even taking nutrients from the soil, so the larger tree ends up killing the smaller one.
In antibiosis it occurs when one organism damages or kills another through a chemical secretion. An example is in the cultures of bacterial consortia, some of which secrete molecules that are harmful to others. Antibiotics play a fundamental role in this type of interaction and their study has helped to understand this process and to improve these drugs (Kong, Schneper, & Mathee, 2010).
