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The changes in the environment are happening every day.
With time the genetic variation in an organism helps them to adapt more due to natural selection.
These variations in a population enable the stability of various species.
It does that by preventing them from getting wiped out during adverse conditions.
Hence, the creation of variation helps in promoting survival.
The study of evolution and classification of organisms are interlinked in phylogenetic classification system.
Classification of different types of organisms in groups is based on similarities and dissimilarities between them.
Phylogenetic classification refers to the classification of organisms based on their descent from a common ancestor.
The evolutionary ancestry is the foundation of the phylogenetic classification system. It is based on life's evolution and depicts the genetic relationships between organisms.
It produces cladograms, which are groups of organisms that include an ancestor species and its descendants.
Question 1. What do you understand by the term genetic drift?
Answer. Natural selection can have a big influence on which traits survive in a population. Random variations in gene variants are, nonetheless, encountered frequently. Genetic drift is the term for this phenomenon. In a small population, genetic drift is defined as a change in the frequency of an existing allele. A gene variant may vanish from the population due to genetic drift, reducing genetic variation.
Question 2. How is the progeny's genetic contribution from both male and female parents ensured?
Answer. Each human being's body contains 23 pairs of chromosomes in its somatic cells. 22 pairs of chromosomes are known as autosomes, and one pair is known as sex chromosomes, which are symbolised by the letters X and Y. In females, there are two X chromosomes, while males have one X and one Y chromosome. Meiosis happens during gametogenesis (gamete production), and the gametes receive half of their chromosomes. Male gametes have 22 autosomes and either X or Y chromosomes, as a result. In contrast, the female gamete has 22 autosomes and X chromosomes. Male and female gametes merge during sexual reproduction, and the number of chromosomes in the zygote is restored. Thus, From Male - From the male parent, the child obtains 22 autosomes and one X or Y chromosome. From Female - from the female parent, the child obtains 22 autosomes and one X chromosome.