Populations in science

SCIENCE IN ACTION

By MICHAEL JOHN UGLO
THIS lecture is on numbers of organisms referred to as population or populations.
Welcome to you all as always. In an endeavor to see more than just one organism than you have a variety of organisms at least at a molecular level even in that population of the same species there is biodiversity.
The loci of the chromosome and a homologous chromosome and alleles of genes that are not blended but are just mixed says it all of a haploid cell programmed diploid organism. This is the fact with sexually reproducing organisms including both plants and animals.
Population can generate numbers and relationships in the olden days like the father of heredity studies depicted, the Austrian Gregory Mendel in his test to explain how traits are transmitted through the germ cells of the pea plants which grants him this title of father of genetics.
Knowing the genomes of a cell can help a scientist to make accurate predictions on the characteristics of the progeny through the union of two germ cells, one being a male pollen or sperm and a female ovum. This gives rise to the unprecedented fields of genetic engineering and biotechnology.
Computer modeling can be used to artificially programme to come up with individual characters that are desirable. One such is to genetically engineer individuals who can be free from genetically inherited diseases or coming up with people who can play basketball, football or athletics.
Organism numbers – population
In the study of ecology, population is taken to be the number of a similar kind of an organism or a species in a particular area at any one time. These are organisms, whether plants, animals or even microbes under study.
The populations are capable of reproducing or interbreeding among themselves with the exchange of the sex cells called the gametes which contain the genetic information or blueprint for the offspring or progeny.
That is, they can produce their young which are fertile and therefore can also interbreed among themselves to produce new young. Hence, they are of the same species and that is when they inter-breed they can produce fertile offspring.
A horse and a donkey may look similar but they are not of the same species. That is, when they interbreed, they can produce a young, called a mule. Then, when the mule is crossed with any horse or a donkey or another mule, they cannot produce a new young. This basically concludes that a horse and a donkey are not of the same species although physically they may look similar.
Gene pools
A sizable gene pool in a particular geographical location for a specific species to interbreed maintain a population known as a gamodeme. A gamodeme can expand into very bigger populations of the interbreeding species of a population.
At best, that huge interbreeding species population can proceed from a gamodeme into a panmictic. This is when a very huge population of a particular species come about.
In nature, this normally does not happen because individuals of the same species choose their own partners to mate according to their preferences. Also, their dispersal methods can be limited given certain adverse environmental conditions in the abiotic as well as biotic factors.
Furthermore, there can also be natural disasters that can isolate a certain population of a species to function as a gamodeme instead of a panmictic. There are so many other reasons such as the processes of speciation as a result of geographical isolations.
Speciation happens when an isolated species, inbreed instead of interbreeding so they evolve within the similar alleles and chromosomes of the gene bank that result in homozygotes which can either be fatal or beneficial.
This homozygosity can result in recessive or dominant alleles that further evolve down the generations to result in the birth of new species in the different respective biogeographic locations to maintain a gamodeme.
The biogeographical isolations can result in line breeding, pure-line breeding and backcrossing. This will result in events such as random fertilization known as allogamous gamodemes as well as self-fertilization known as autogamous gamodemes.

In human populations the migrations are considered to state a population of a particular place studied in a field called demography. The individuals or people migrating into a particular place is called immigrations and moving out of the same in a population is called emigrations.
The fertility of a population is the sexually active population that can successfully mate and reproduce. The net population is the total number of people at a particular place at any one time. This is obtained from immigrations plus total births added to the total population minus the emigrations with total deaths to give the total net population (that is: immigrations + total births + total population) – emigrations + total deaths = net population).

My Prayer for PNG today is: “Oh, when I come to the end of my journey, Weary of life and the battle is won; Carrying the staff and the cross of redemption, He’ll understand and say, “Well done…”
Next week: The sciences of our body

• Michael Uglo in the author of the science textbook “Science in PNG, Pacific, Asia & Caribbean” and a lecturer in Avionics, Auto- Piloting and Aircraft Engineering. Please send comments to: [email protected]