ABC of Evolution: Part II

Mazhar Abbas Khan


Survival of the fittest, from an evolutionary point of view, fitness in this sentence is related to the ability of reproduction(Increasing it’s race). The more children an animal has in its life, the more fit it will be.

There are two types of biological fitness.

Absolute Fitness and Relative Fitness:

Absolute fitness means how many children an organism produces in its lifetime. For example, if a deer falls prey to a leopard before it becomes sexually mature and gives birth to its first offspring, then the deer’s absolute fitness will be zero. Because she could not have a single child.
In contrast, take the example of a fruit tree planted in the forest that has been producing many seeds every season for many years and many of these seeds have succeeded in creating a new tree. Biologically this tree is very fit.

Relative fitness shows how many children an organism produces compared to other organisms like itself.
If one deer manages to produce two offspring each breeding season but the other deer can produce only one offspring, then the relative fitness of the first deer is higher than that of the second. Many situations and events affect fitness.

Not necessarily that all the zygotes or seeds that a living thing produces can be successfully transformed into a new living thing, it is also possible for an organism to die during development. It is also possible to develop successfully but not reach the reproductive age, become prey, and die. It is also not necessary for them to reach the reproductive age and find a partner for reproduction. And it is also possible that their gametes (sperms and eggs) will not be successfully fertilized after finding a partner.


Homo in Latin means man. In biological classification is the name of this genus of Kingdom Anemia in which the present humans have been categorized. One of the common misconceptions about human evolution is that modern humans are the only human beings on the planet to have evolved. Not at all.

The scientific name for modern humans is Homo sapiens, but there were other human species in the Homo genus that became extinct like dinosaurs. But like dinosaurs, their fossils are evidence of their existence in the past. In addition to Homo sapiens, the genus Homo also contains the extinct Homo erectus, Homo neanderthalins, Homo habilis, etc.

Insecticide resistance:

Another misconception about evolution is that the principles of evolution cannot be observed in the context of human life. Such things only show that man does not know what evolutionary principles are. The chemicals used to kill different types of insects are called insecticides. You may have heard the name Morten used at home, it is an insecticide. Insecticides are also present in crop sprays. Observations show that repeated use of the same insecticide on a specific area can cause the insecticide to become ineffective.
That is, resistance to insecticides occurs in insects, due to evolution.

Evolution is defined at the genetic level:

“The changing of genetic composition of a population over time”. When insecticides are sprayed on insecticides, the effect is greater on some insects and less on others. Some insects contain genes that are more effective in counteracting the effects of insecticides and some contain genes that are less effective.

This means that in the presence of a sprayed environment, insects with more effective genes will have a greater chance. So that they can carry on their generation. That is, the number of effective genes containing insects will increase in each next generation
And less effective genes containing insects will disappear from the population. This means that the genetic makeup of the population will change.

Mazhar Abbas Khan From Layyah, Graduated from Government College Mailsi, you can reach him through